Ref-counted rewrite of ChannelManager.

The complexity of the last ChannelManager and potentially usage of it as well caused race conditions and deadlocks in loopback voe_auto_test. This ref-counted solution takes no long-term locks, uses less locks overall and is significantly easier to understand.

ScopedChannel has been split up into a ChannelOwner with a reference to a channel and an Iterator over ChannelManager. Previous code was really used for both things. ChannelOwner is used as a shared pointer to a channel object, while an Iterator should work as expected.

BUG=2081
R=tommi@webrtc.org, xians@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/1802004

git-svn-id: http://webrtc.googlecode.com/svn/trunk/webrtc@4502 4adac7df-926f-26a2-2b94-8c16560cd09d

28 files changed, 568 insertions, 1059 deletions

diff --git a/voice_engine/Android.mk b/voice_engine/Android.mk
index 5040f17a..4c5fa592 100644
--- a/voice_engine/Android.mk
+++ b/voice_engine/Android.mk
@@ -20,7 +20,6 @@ LOCAL_SRC_FILES := \
     audio_frame_operations.cc \
     channel.cc \
     channel_manager.cc \
-    channel_manager_base.cc \
     dtmf_inband.cc \
     dtmf_inband_queue.cc \
     level_indicator.cc \
diff --git a/voice_engine/channel_manager.cc b/voice_engine/channel_manager.cc
index 4b203176..6cf935d1 100644
--- a/voice_engine/channel_manager.cc
+++ b/voice_engine/channel_manager.cc
@@ -8,154 +8,117 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
-#include "webrtc/voice_engine/channel.h"
 #include "webrtc/voice_engine/channel_manager.h"
 
-namespace webrtc
-{
+#include "webrtc/voice_engine/channel.h"
 
-namespace voe
-{
+namespace webrtc {
+namespace voe {
 
-ChannelManager::ChannelManager(uint32_t instanceId) :
-    ChannelManagerBase(),
-    _instanceId(instanceId)
-{
-}
+ChannelOwner::ChannelOwner(class Channel* channel)
+    : channel_ref_(new ChannelRef(channel)) {}
 
-ChannelManager::~ChannelManager()
-{
-    ChannelManagerBase::DestroyAllItems();
+ChannelOwner::ChannelOwner(const ChannelOwner& channel_owner)
+    : channel_ref_(channel_owner.channel_ref_) {
+  ++channel_ref_->ref_count;
 }
 
-bool ChannelManager::CreateChannel(int32_t& channelId)
-{
-    return ChannelManagerBase::CreateItem(channelId);
+ChannelOwner::~ChannelOwner() {
+  if (--channel_ref_->ref_count == 0)
+    delete channel_ref_;
 }
 
-int32_t ChannelManager::DestroyChannel(int32_t channelId)
-{
-    Channel* deleteChannel =
-        static_cast<Channel*> (ChannelManagerBase::RemoveItem(channelId));
-    if (!deleteChannel)
-    {
-        return -1;
-    }
-    delete deleteChannel;
-    return 0;
-}
+ChannelOwner& ChannelOwner::operator=(const ChannelOwner& other) {
+  if (other.channel_ref_ == channel_ref_)
+    return *this;
 
-int32_t ChannelManager::NumOfChannels() const
-{
-    return ChannelManagerBase::NumOfItems();
-}
+  if (--channel_ref_->ref_count == 0)
+    delete channel_ref_;
 
-int32_t ChannelManager::MaxNumOfChannels() const
-{
-    return ChannelManagerBase::MaxNumOfItems();
-}
+  channel_ref_ = other.channel_ref_;
+  ++channel_ref_->ref_count;
 
-void* ChannelManager::NewItem(int32_t itemID)
-{
-    Channel* channel;
-    if (Channel::CreateChannel(channel, itemID, _instanceId) == -1)
-    {
-        return NULL;
-    }
-    return static_cast<void*> (channel);
+  return *this;
 }
 
-void ChannelManager::DeleteItem(void* item)
-{
-    Channel* deleteItem = static_cast<Channel*> (item);
-    delete deleteItem;
-}
+ChannelOwner::ChannelRef::ChannelRef(class Channel* channel)
+    : channel(channel), ref_count(1) {}
 
-Channel* ChannelManager::GetChannel(int32_t channelId) const
-{
-    return static_cast<Channel*> (ChannelManagerBase::GetItem(channelId));
-}
+ChannelManager::ChannelManager(uint32_t instance_id)
+    : instance_id_(instance_id),
+      last_channel_id_(-1),
+      lock_(CriticalSectionWrapper::CreateCriticalSection()) {}
+
+ChannelOwner ChannelManager::CreateChannel() {
+  Channel* channel;
+  Channel::CreateChannel(channel, ++last_channel_id_, instance_id_);
+  ChannelOwner channel_owner(channel);
+
+  CriticalSectionScoped crit(lock_.get());
 
-void ChannelManager::ReleaseChannel()
-{
-    ChannelManagerBase::ReleaseItem();
+  channels_.push_back(channel_owner);
+
+  return channel_owner;
 }
 
-void ChannelManager::GetChannelIds(int32_t* channelsArray,
-                                   int32_t& numOfChannels) const
-{
-    ChannelManagerBase::GetItemIds(channelsArray, numOfChannels);
+ChannelOwner ChannelManager::GetChannel(int32_t channel_id) {
+  CriticalSectionScoped crit(lock_.get());
+
+  for (size_t i = 0; i < channels_.size(); ++i) {
+    if (channels_[i].channel()->ChannelId() == channel_id)
+      return channels_[i];
+  }
+  return ChannelOwner(NULL);
 }
 
-void ChannelManager::GetChannels(MapWrapper& channels) const
-{
-    ChannelManagerBase::GetChannels(channels);
+void ChannelManager::GetAllChannels(std::vector<ChannelOwner>* channels) {
+  CriticalSectionScoped crit(lock_.get());
+
+  *channels = channels_;
 }
 
-ScopedChannel::ScopedChannel(ChannelManager& chManager) :
-    _chManager(chManager),
-    _channelPtr(NULL)
-{
-    // Copy all existing channels to the local map.
-    // It is not possible to utilize the ChannelPtr() API after
-    // this constructor. The intention is that this constructor
-    // is used in combination with the scoped iterator.
-    _chManager.GetChannels(_channels);
+void ChannelManager::DestroyChannel(int32_t channel_id) {
+  CriticalSectionScoped crit(lock_.get());
+  assert(channel_id >= 0);
+
+  for (std::vector<ChannelOwner>::iterator it = channels_.begin();
+       it != channels_.end();
+       ++it) {
+    if (it->channel()->ChannelId() == channel_id) {
+      channels_.erase(it);
+      break;
+    }
+  }
 }
 
-ScopedChannel::ScopedChannel(ChannelManager& chManager,
-                             int32_t channelId) :
-    _chManager(chManager),
-    _channelPtr(NULL)
-{
-    _channelPtr = _chManager.GetChannel(channelId);
+void ChannelManager::DestroyAllChannels() {
+  CriticalSectionScoped crit(lock_.get());
+  channels_.clear();
 }
 
-ScopedChannel::~ScopedChannel()
-{
-    if (_channelPtr != NULL || _channels.Size() != 0)
-    {
-        _chManager.ReleaseChannel();
-    }
+size_t ChannelManager::NumOfChannels() const {
+  CriticalSectionScoped crit(lock_.get());
+  return channels_.size();
+}
 
-    // Delete the map
-    while (_channels.Erase(_channels.First()) == 0)
-        ;
+ChannelManager::Iterator::Iterator(ChannelManager* channel_manager)
+    : iterator_pos_(0) {
+  channel_manager->GetAllChannels(&channels_);
 }
 
-Channel* ScopedChannel::ChannelPtr()
-{
-    return _channelPtr;
+Channel* ChannelManager::Iterator::GetChannel() {
+  if (iterator_pos_ < channels_.size())
+    return channels_[iterator_pos_].channel();
+  return NULL;
 }
 
-Channel* ScopedChannel::GetFirstChannel(void*& iterator) const
-{
-    MapItem* it = _channels.First();
-    iterator = (void*) it;
-    if (!it)
-    {
-        return NULL;
-    }
-    return static_cast<Channel*> (it->GetItem());
+bool ChannelManager::Iterator::IsValid() {
+  return iterator_pos_ < channels_.size();
 }
 
-Channel* ScopedChannel::GetNextChannel(void*& iterator) const
-{
-    MapItem* it = (MapItem*) iterator;
-    if (!it)
-    {
-        iterator = NULL;
-        return NULL;
-    }
-    it = _channels.Next(it);
-    iterator = (void*) it;
-    if (!it)
-    {
-        return NULL;
-    }
-    return static_cast<Channel*> (it->GetItem());
+void ChannelManager::Iterator::Increment() {
+  ++iterator_pos_;
 }
 
 }  // namespace voe
-
 }  // namespace webrtc
diff --git a/voice_engine/channel_manager.h b/voice_engine/channel_manager.h
index 723ff043..4efeb15f 100644
--- a/voice_engine/channel_manager.h
+++ b/voice_engine/channel_manager.h
@@ -11,79 +11,108 @@
 #ifndef WEBRTC_VOICE_ENGINE_CHANNEL_MANAGER_H
 #define WEBRTC_VOICE_ENGINE_CHANNEL_MANAGER_H
 
-#include "webrtc/typedefs.h"
-#include "webrtc/voice_engine/channel_manager_base.h"
+#include <vector>
 
-namespace webrtc
-{
+#include "webrtc/system_wrappers/interface/atomic32.h"
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+#include "webrtc/system_wrappers/interface/critical_section_wrapper.h"
+#include "webrtc/system_wrappers/interface/scoped_ptr.h"
+#include "webrtc/typedefs.h"
 
-namespace voe
-{
+namespace webrtc {
+namespace voe {
 
-class ScopedChannel;
 class Channel;
 
-class ChannelManager: private ChannelManagerBase
-{
-    friend class ScopedChannel;
-
-public:
-    bool CreateChannel(int32_t& channelId);
-
-    int32_t DestroyChannel(int32_t channelId);
-
-    int32_t MaxNumOfChannels() const;
-
-    int32_t NumOfChannels() const;
-
-    void GetChannelIds(int32_t* channelsArray,
-                       int32_t& numOfChannels) const;
-
-    ChannelManager(uint32_t instanceId);
-
-    ~ChannelManager();
+// Shared-pointer implementation for keeping track of Channels. The underlying
+// shared instance will be dropped when no more ChannelOwners point to it.
+//
+// One common source of ChannelOwner instances are
+// ChannelManager::CreateChannel() and ChannelManager::GetChannel(...).
+// It has a similar use case to shared_ptr in C++11. Should this move to C++11
+// in the future, this class should be replaced by exactly that.
+//
+// To access the underlying Channel, use .channel().
+// IsValid() implements a convenience method as an alternative for checking
+// whether the underlying pointer is NULL or not.
+//
+// Channel channel_owner = channel_manager.GetChannel(channel_id);
+// if (channel_owner.IsValid())
+//   channel_owner.channel()->...;
+//
+class ChannelOwner {
+ public:
+  explicit ChannelOwner(Channel* channel);
+  ChannelOwner(const ChannelOwner& channel_owner);
+
+  ~ChannelOwner();
+
+  ChannelOwner& operator=(const ChannelOwner& other);
+
+  Channel* channel() { return channel_ref_->channel.get(); }
+  bool IsValid() { return channel_ref_->channel.get() != NULL; }
+ private:
+  // Shared instance of a Channel. Copying ChannelOwners increase the reference
+  // count and destroying ChannelOwners decrease references. Channels are
+  // deleted when no references to them are held.
+  struct ChannelRef {
+    ChannelRef(Channel* channel);
+    const scoped_ptr<Channel> channel;
+    Atomic32 ref_count;
+  };
+
+  ChannelRef* channel_ref_;
+};
 
-private:
-    ChannelManager(const ChannelManager&);
+class ChannelManager {
+ public:
+  ChannelManager(uint32_t instance_id);
 
-    ChannelManager& operator=(const ChannelManager&);
+  // Upon construction of an Iterator it will grab a copy of the channel list of
+  // the ChannelManager. The iteration will then occur over this state, not the
+  // current one of the ChannelManager. As the Iterator holds its own references
+  // to the Channels, they will remain valid even if they are removed from the
+  // ChannelManager.
+  class Iterator {
+   public:
+    explicit Iterator(ChannelManager* channel_manager);
 
-    Channel* GetChannel(int32_t channelId) const;
+    Channel* GetChannel();
+    bool IsValid();
 
-    void GetChannels(MapWrapper& channels) const;
+    void Increment();
 
-    void ReleaseChannel();
+   private:
+    size_t iterator_pos_;
+    std::vector<ChannelOwner> channels_;
 
-    virtual void* NewItem(int32_t itemID);
+    DISALLOW_COPY_AND_ASSIGN(Iterator);
+  };
 
-    virtual void DeleteItem(void* item);
+  // CreateChannel will always return a valid ChannelOwner instance.
+  ChannelOwner CreateChannel();
 
-    uint32_t _instanceId;
-};
+  // ChannelOwner.channel() will be NULL if channel_id is invalid or no longer
+  // exists. This should be checked with ChannelOwner::IsValid().
+  ChannelOwner GetChannel(int32_t channel_id);
+  void GetAllChannels(std::vector<ChannelOwner>* channels);
 
-class ScopedChannel
-{
-public:
-    // Can only be created by the channel manager
-    ScopedChannel(ChannelManager& chManager);
+  void DestroyChannel(int32_t channel_id);
+  void DestroyAllChannels();
 
-    ScopedChannel(ChannelManager& chManager, int32_t channelId);
+  size_t NumOfChannels() const;
 
-    Channel* ChannelPtr();
+ private:
+  uint32_t instance_id_;
 
-    Channel* GetFirstChannel(void*& iterator) const;
+  Atomic32 last_channel_id_;
 
-    Channel* GetNextChannel(void*& iterator) const;
+  scoped_ptr<CriticalSectionWrapper> lock_;
+  std::vector<ChannelOwner> channels_;
 
-    ~ScopedChannel();
-private:
-    ChannelManager& _chManager;
-    Channel* _channelPtr;
-    MapWrapper _channels;
+  DISALLOW_COPY_AND_ASSIGN(ChannelManager);
 };
-
 }  // namespace voe
-
 }  // namespace webrtc
 
 #endif  // WEBRTC_VOICE_ENGINE_CHANNEL_MANAGER_H
diff --git a/voice_engine/channel_manager_base.cc b/voice_engine/channel_manager_base.cc
deleted file mode 100644
index 10cb11f7..00000000
--- a/voice_engine/channel_manager_base.cc
+++ /dev/null
@@ -1,228 +0,0 @@
-/*
- *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
- *
- *  Use of this source code is governed by a BSD-style license
- *  that can be found in the LICENSE file in the root of the source
- *  tree. An additional intellectual property rights grant can be found
- *  in the file PATENTS.  All contributing project authors may
- *  be found in the AUTHORS file in the root of the source tree.
- */
-
-#include "webrtc/voice_engine/channel_manager_base.h"
-
-#include <assert.h>
-
-#include "webrtc/system_wrappers/interface/critical_section_wrapper.h"
-#include "webrtc/system_wrappers/interface/rw_lock_wrapper.h"
-
-namespace webrtc
-{
-
-namespace voe
-{
-
-ChannelManagerBase::ChannelManagerBase() :
-    _itemsCritSectPtr(CriticalSectionWrapper::CreateCriticalSection()),
-    _itemsRWLockPtr(RWLockWrapper::CreateRWLock())
-{
-    for (int i = 0; i < kVoiceEngineMaxNumChannels; i++)
-    {
-        _freeItemIds[i] = true;
-    }
-}
-
-ChannelManagerBase::~ChannelManagerBase()
-{
-    if (_itemsRWLockPtr)
-    {
-        delete _itemsRWLockPtr;
-        _itemsRWLockPtr = NULL;
-    }
-    if (_itemsCritSectPtr)
-    {
-        delete _itemsCritSectPtr;
-        _itemsCritSectPtr = NULL;
-    }
-}
-
-bool ChannelManagerBase::GetFreeItemId(int32_t& itemId)
-{
-    CriticalSectionScoped cs(_itemsCritSectPtr);
-    int32_t i(0);
-    while (i < kVoiceEngineMaxNumChannels)
-    {
-        if (_freeItemIds[i])
-        {
-            itemId = i;
-            _freeItemIds[i] = false;
-            return true;
-        }
-        i++;
-    }
-    return false;
-}
-
-void ChannelManagerBase::AddFreeItemId(int32_t itemId)
-{
-    assert(itemId < kVoiceEngineMaxNumChannels);
-    _freeItemIds[itemId] = true;
-}
-
-void ChannelManagerBase::RemoveFreeItemIds()
-{
-    for (int i = 0; i < kVoiceEngineMaxNumChannels; i++)
-    {
-        _freeItemIds[i] = false;
-    }
-}
-
-bool ChannelManagerBase::CreateItem(int32_t& itemId)
-{
-    _itemsCritSectPtr->Enter();
-    void* itemPtr;
-    itemId = -1;
-    const bool success = GetFreeItemId(itemId);
-    if (!success)
-    {
-        _itemsCritSectPtr->Leave();
-        return false;
-    }
-    itemPtr = NewItem(itemId);
-    if (!itemPtr)
-    {
-        _itemsCritSectPtr->Leave();
-        return false;
-    }
-    _itemsCritSectPtr->Leave();
-    InsertItem(itemId, itemPtr);
-
-    return true;
-}
-
-void ChannelManagerBase::InsertItem(int32_t itemId, void* item)
-{
-    CriticalSectionScoped cs(_itemsCritSectPtr);
-    assert(!_items.Find(itemId));
-    _items.Insert(itemId, item);
-}
-
-void*
-ChannelManagerBase::RemoveItem(int32_t itemId)
-{
-    CriticalSectionScoped cs(_itemsCritSectPtr);
-    WriteLockScoped wlock(*_itemsRWLockPtr);
-    MapItem* it = _items.Find(itemId);
-    if (!it)
-    {
-        return 0;
-    }
-    void* returnItem = it->GetItem();
-    _items.Erase(it);
-    AddFreeItemId(itemId);
-
-    return returnItem;
-}
-
-void ChannelManagerBase::DestroyAllItems()
-{
-    CriticalSectionScoped cs(_itemsCritSectPtr);
-    MapItem* it = _items.First();
-    while (it)
-    {
-        DeleteItem(it->GetItem());
-        _items.Erase(it);
-        it = _items.First();
-    }
-    RemoveFreeItemIds();
-}
-
-int32_t ChannelManagerBase::NumOfItems() const
-{
-    return _items.Size();
-}
-
-int32_t ChannelManagerBase::MaxNumOfItems() const
-{
-    return static_cast<int32_t> (kVoiceEngineMaxNumChannels);
-}
-
-void*
-ChannelManagerBase::GetItem(int32_t itemId) const
-{
-    CriticalSectionScoped cs(_itemsCritSectPtr);
-    MapItem* it = _items.Find(itemId);
-    if (!it)
-    {
-        return 0;
-    }
-    _itemsRWLockPtr->AcquireLockShared();
-    return it->GetItem();
-}
-
-void*
-ChannelManagerBase::GetFirstItem(void*& iterator) const
-{
-    CriticalSectionScoped cs(_itemsCritSectPtr);
-    MapItem* it = _items.First();
-    iterator = (void*) it;
-    if (!it)
-    {
-        return 0;
-    }
-    return it->GetItem();
-}
-
-void*
-ChannelManagerBase::GetNextItem(void*& iterator) const
-{
-    CriticalSectionScoped cs(_itemsCritSectPtr);
-    MapItem* it = (MapItem*) iterator;
-    if (!it)
-    {
-        iterator = 0;
-        return 0;
-    }
-    it = _items.Next(it);
-    iterator = (void*) it;
-    if (!it)
-    {
-        return 0;
-    }
-    return it->GetItem();
-}
-
-void ChannelManagerBase::ReleaseItem()
-{
-    _itemsRWLockPtr->ReleaseLockShared();
-}
-
-void ChannelManagerBase::GetItemIds(int32_t* channelsArray,
-                                    int32_t& numOfChannels) const
-{
-    MapItem* it = _items.First();
-    numOfChannels = (numOfChannels <= _items.Size()) ?
-        numOfChannels : _items.Size();
-    for (int i = 0; i < numOfChannels && it != NULL; i++)
-    {
-        channelsArray[i] = it->GetId();
-        it = _items.Next(it);
-    }
-}
-
-void ChannelManagerBase::GetChannels(MapWrapper& channels) const
-{
-    CriticalSectionScoped cs(_itemsCritSectPtr);
-    if (_items.Size() == 0)
-    {
-        return;
-    }
-    _itemsRWLockPtr->AcquireLockShared();
-    for (MapItem* it = _items.First(); it != NULL; it = _items.Next(it))
-    {
-        channels.Insert(it->GetId(), it->GetItem());
-    }
-}
-
-}  // namespace voe
-
-}  // namespace webrtc
diff --git a/voice_engine/channel_manager_base.h b/voice_engine/channel_manager_base.h
deleted file mode 100644
index 1db19033..00000000
--- a/voice_engine/channel_manager_base.h
+++ /dev/null
@@ -1,87 +0,0 @@
-/*
- *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
- *
- *  Use of this source code is governed by a BSD-style license
- *  that can be found in the LICENSE file in the root of the source
- *  tree. An additional intellectual property rights grant can be found
- *  in the file PATENTS.  All contributing project authors may
- *  be found in the AUTHORS file in the root of the source tree.
- */
-
-#ifndef WEBRTC_VOICE_ENGINE_CHANNEL_MANAGER_BASE_H
-#define WEBRTC_VOICE_ENGINE_CHANNEL_MANAGER_BASE_H
-
-#include "webrtc/system_wrappers/interface/map_wrapper.h"
-#include "webrtc/typedefs.h"
-#include "webrtc/voice_engine/voice_engine_defines.h"
-
-namespace webrtc
-{
-class CriticalSectionWrapper;
-class RWLockWrapper;
-
-namespace voe
-{
-
-class ScopedChannel;
-class Channel;
-
-class ChannelManagerBase
-{
-protected:
-    bool CreateItem(int32_t& itemId);
-
-    void InsertItem(int32_t itemId, void* item);
-
-    void* RemoveItem(int32_t itemId);
-
-    void* GetItem(int32_t itemId) const;
-
-    void* GetFirstItem(void*& iterator) const ;
-
-    void* GetNextItem(void*& iterator) const;
-
-    void ReleaseItem();
-
-    void AddFreeItemId(int32_t itemId);
-
-    bool GetFreeItemId(int32_t& itemId);
-
-    void RemoveFreeItemIds();
-
-    void DestroyAllItems();
-
-    int32_t NumOfItems() const;
-
-    int32_t MaxNumOfItems() const;
-
-    void GetItemIds(int32_t* channelsArray,
-                    int32_t& numOfChannels) const;
-
-    void GetChannels(MapWrapper& channels) const;
-
-    virtual void* NewItem(int32_t itemId) = 0;
-
-    virtual void DeleteItem(void* item) = 0;
-
-    ChannelManagerBase();
-
-    virtual ~ChannelManagerBase();
-
-private:
-    // Protects _items and _freeItemIds
-    CriticalSectionWrapper* _itemsCritSectPtr;
-
-    MapWrapper _items;
-
-    bool _freeItemIds[kVoiceEngineMaxNumChannels];
-
-    // Protects channels from being destroyed while being used
-    RWLockWrapper* _itemsRWLockPtr;
-};
-
-}  // namespace voe
-
-}  // namespace webrtc
-
-#endif  // WEBRTC_VOICE_ENGINE_CHANNEL_MANAGER_BASE_H
diff --git a/voice_engine/include/voe_base.h b/voice_engine/include/voe_base.h
index 1a06c2ee..de483b43 100644
--- a/voice_engine/include/voe_base.h
+++ b/voice_engine/include/voe_base.h
@@ -130,9 +130,6 @@ public:
     // Terminates all VoiceEngine functions and releses allocated resources.
     virtual int Terminate() = 0;
 
-    // Retrieves the maximum number of channels that can be created.
-    virtual int MaxNumOfChannels() = 0;
-
     // Creates a new channel and allocates the required resources for it.
     virtual int CreateChannel() = 0;
 
diff --git a/voice_engine/shared_data.cc b/voice_engine/shared_data.cc
index e993778b..843d5db6 100644
--- a/voice_engine/shared_data.cc
+++ b/voice_engine/shared_data.cc
@@ -76,32 +76,17 @@ void SharedData::set_audio_processing(AudioProcessing* audioproc) {
   _outputMixerPtr->SetAudioProcessingModule(audioproc);
 }
 
-uint16_t SharedData::NumOfSendingChannels()
-{
-    int32_t numOfChannels = _channelManager.NumOfChannels();
-    if (numOfChannels <= 0)
-    {
-        return 0;
-    }
+uint16_t SharedData::NumOfSendingChannels() {
+  ChannelManager::Iterator it(&_channelManager);
+  uint16_t sending_channels = 0;
 
-    uint16_t nChannelsSending(0);
-    int32_t* channelsArray = new int32_t[numOfChannels];
+  for (ChannelManager::Iterator it(&_channelManager); it.IsValid();
+       it.Increment()) {
+    if (it.GetChannel()->Sending())
+      ++sending_channels;
+  }
 
-    _channelManager.GetChannelIds(channelsArray, numOfChannels);
-    for (int i = 0; i < numOfChannels; i++)
-    {
-        voe::ScopedChannel sc(_channelManager, channelsArray[i]);
-        Channel* chPtr = sc.ChannelPtr();
-        if (chPtr)
-        {
-            if (chPtr->Sending())
-            {
-                nChannelsSending++;
-            }
-        }
-    }
-    delete [] channelsArray;
-    return nChannelsSending;
+  return sending_channels;
 }
 
 void SharedData::SetLastError(int32_t error) const {
diff --git a/voice_engine/test/auto_test/standard/rtp_rtcp_test.cc b/voice_engine/test/auto_test/standard/rtp_rtcp_test.cc
index 6fef51cc..1cf64a01 100644
--- a/voice_engine/test/auto_test/standard/rtp_rtcp_test.cc
+++ b/voice_engine/test/auto_test/standard/rtp_rtcp_test.cc
@@ -8,64 +8,39 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
+#include "webrtc/system_wrappers/interface/atomic32.h"
+#include "webrtc/system_wrappers/interface/critical_section_wrapper.h"
+#include "webrtc/system_wrappers/interface/event_wrapper.h"
 #include "webrtc/test/testsupport/fileutils.h"
 #include "webrtc/voice_engine/test/auto_test/fixtures/after_streaming_fixture.h"
 #include "webrtc/voice_engine/test/auto_test/voe_standard_test.h"
 
 class TestRtpObserver : public webrtc::VoERTPObserver {
  public:
-  TestRtpObserver();
-  virtual ~TestRtpObserver();
+  TestRtpObserver()
+      : crit_(voetest::CriticalSectionWrapper::CreateCriticalSection()),
+        changed_ssrc_event_(voetest::EventWrapper::Create()) {}
+  virtual ~TestRtpObserver() {}
   virtual void OnIncomingCSRCChanged(int channel,
                                      unsigned int CSRC,
-                                     bool added);
+                                     bool added) {}
   virtual void OnIncomingSSRCChanged(int channel,
                                      unsigned int SSRC);
-  void Reset();
+  void WaitForChangedSsrc() {
+    // 10 seconds should be enough.
+    EXPECT_EQ(voetest::kEventSignaled, changed_ssrc_event_->Wait(10*1000));
+    changed_ssrc_event_->Reset();
+  }
+  void SetIncomingSsrc(unsigned int ssrc) {
+    voetest::CriticalSectionScoped lock(crit_.get());
+    incoming_ssrc_ = ssrc;
+  }
  public:
-  unsigned int ssrc_[2];
-  unsigned int csrc_[2][2];  // Stores 2 CSRCs for each channel.
-  bool added_[2][2];
-  int size_[2];
+  voetest::scoped_ptr<voetest::CriticalSectionWrapper> crit_;
+  unsigned int incoming_ssrc_;
+  voetest::scoped_ptr<voetest::EventWrapper> changed_ssrc_event_;
 };
 
-TestRtpObserver::TestRtpObserver() {
-  Reset();
-}
-
-TestRtpObserver::~TestRtpObserver() {
-}
-
-void TestRtpObserver::Reset() {
-  for (int i = 0; i < 2; i++) {
-    ssrc_[i] = 0;
-    csrc_[i][0] = 0;
-    csrc_[i][1] = 0;
-    added_[i][0] = false;
-    added_[i][1] = false;
-    size_[i] = 0;
-  }
-}
-
-void TestRtpObserver::OnIncomingCSRCChanged(int channel,
-                                            unsigned int CSRC,
-                                            bool added) {
-  char msg[128];
-  sprintf(msg, "=> OnIncomingCSRCChanged(channel=%d, CSRC=%u, added=%d)\n",
-          channel, CSRC, added);
-  TEST_LOG("%s", msg);
-
-  if (channel > 1)
-    return;  // Not enough memory.
-
-  csrc_[channel][size_[channel]] = CSRC;
-  added_[channel][size_[channel]] = added;
-
-  size_[channel]++;
-  if (size_[channel] == 2)
-    size_[channel] = 0;
-}
-
 void TestRtpObserver::OnIncomingSSRCChanged(int channel,
                                             unsigned int SSRC) {
   char msg[128];
@@ -73,7 +48,11 @@ void TestRtpObserver::OnIncomingSSRCChanged(int channel,
           SSRC);
   TEST_LOG("%s", msg);
 
-  ssrc_[channel] = SSRC;
+  {
+    voetest::CriticalSectionScoped lock(crit_.get());
+    if (incoming_ssrc_ == SSRC)
+      changed_ssrc_event_->Set();
+  }
 }
 
 class RtcpAppHandler : public webrtc::VoERTCPObserver {
@@ -277,27 +256,23 @@ TEST_F(RtpRtcpTest, ObserverGetsNotifiedOnSsrcChange) {
   TestRtpObserver rtcp_observer;
   EXPECT_EQ(0, voe_rtp_rtcp_->RegisterRTPObserver(
       channel_, rtcp_observer));
-  rtcp_observer.Reset();
 
   unsigned int new_ssrc = 7777;
   EXPECT_EQ(0, voe_base_->StopSend(channel_));
+  rtcp_observer.SetIncomingSsrc(new_ssrc);
   EXPECT_EQ(0, voe_rtp_rtcp_->SetLocalSSRC(channel_, new_ssrc));
   EXPECT_EQ(0, voe_base_->StartSend(channel_));
 
-  Sleep(500);
-
-  // Verify we got the new SSRC.
-  EXPECT_EQ(new_ssrc, rtcp_observer.ssrc_[0]);
+  rtcp_observer.WaitForChangedSsrc();
 
   // Now try another SSRC.
   unsigned int newer_ssrc = 1717;
   EXPECT_EQ(0, voe_base_->StopSend(channel_));
+  rtcp_observer.SetIncomingSsrc(newer_ssrc);
   EXPECT_EQ(0, voe_rtp_rtcp_->SetLocalSSRC(channel_, newer_ssrc));
   EXPECT_EQ(0, voe_base_->StartSend(channel_));
 
-  Sleep(500);
-
-  EXPECT_EQ(newer_ssrc, rtcp_observer.ssrc_[0]);
+  rtcp_observer.WaitForChangedSsrc();
 
   EXPECT_EQ(0, voe_rtp_rtcp_->DeRegisterRTPObserver(channel_));
 }
diff --git a/voice_engine/test/auto_test/standard/voe_base_misc_test.cc b/voice_engine/test/auto_test/standard/voe_base_misc_test.cc
index 8d8713c8..736ff087 100644
--- a/voice_engine/test/auto_test/standard/voe_base_misc_test.cc
+++ b/voice_engine/test/auto_test/standard/voe_base_misc_test.cc
@@ -17,10 +17,6 @@ class VoeBaseMiscTest : public BeforeInitializationFixture {
 
 using namespace testing;
 
-TEST_F(VoeBaseMiscTest, MaxNumChannelsIs100) {
-  EXPECT_EQ(100, voe_base_->MaxNumOfChannels());
-}
-
 TEST_F(VoeBaseMiscTest, GetVersionPrintsSomeUsefulInformation) {
   char char_buffer[1024];
   memset(char_buffer, 0, sizeof(char_buffer));
diff --git a/voice_engine/test/auto_test/voe_extended_test.cc b/voice_engine/test/auto_test/voe_extended_test.cc
index 9568e89c..c569aaab 100644
--- a/voice_engine/test/auto_test/voe_extended_test.cc
+++ b/voice_engine/test/auto_test/voe_extended_test.cc
@@ -45,6 +45,8 @@ extern void* globalJavaVM;
 extern void* globalContext;
 #endif
 
+static const int kTestMaxNumChannels = 100;
+
 // ----------------------------------------------------------------------------
 // External AudioDeviceModule implementation
 // ----------------------------------------------------------------------------
@@ -464,24 +466,13 @@ int VoEExtendedTest::TestBase() {
   // >> end of Init(AudioDeviceModule)
   // ------------------------------------------------------------------------
 
-  ///////////////////////////
-  // MaxNumOfChannels
-  TEST(MaxNumOfChannels);
-  ANL();
-  TEST_MUSTPASS(voe_base_->MaxNumOfChannels() < 0);
-  MARK();
-  ANL();
-  AOK();
-  ANL();
-  ANL();
-
   ////////////////////////
   // CreateChannel
   // DeleteChannel
 
   int i;
   int channel;
-  int nChannels(voe_base_->MaxNumOfChannels());
+  static const int kTestMaxNumChannels = 100;
 
   TEST(CreateChannel);
   ANL();
@@ -511,7 +502,7 @@ int VoEExtendedTest::TestBase() {
     MARK();
   }
   // create max number of channels
-  for (i = 0; i < nChannels; i++) {
+  for (i = 0; i < kTestMaxNumChannels; i++) {
     channel = voe_base_->CreateChannel();
     MARK();
     TEST_MUSTPASS(channel != i);
@@ -520,7 +511,8 @@ int VoEExtendedTest::TestBase() {
   MARK(); // should fail since no more channels can now be created
   TEST_MUSTPASS(channel != -1);
 
-  int aChannel = (((nChannels - 17) > 0) ? (nChannels - 17) : 0);
+  int aChannel =
+      (((kTestMaxNumChannels - 17) > 0) ? (kTestMaxNumChannels - 17) : 0);
   TEST_MUSTPASS(voe_base_->DeleteChannel(aChannel));
   MARK();
   channel = voe_base_->CreateChannel();
@@ -528,7 +520,7 @@ int VoEExtendedTest::TestBase() {
   TEST_MUSTPASS(channel != aChannel);
 
   // delete all created channels
-  for (i = 0; i < nChannels; i++) {
+  for (i = 0; i < kTestMaxNumChannels; i++) {
     TEST_MUSTPASS(voe_base_->DeleteChannel(i));
     MARK();
   }
@@ -608,15 +600,15 @@ int VoEExtendedTest::TestBase() {
 
   // Multi-channel tests
 
-  for (i = 0; i < voe_base_->MaxNumOfChannels(); i++) {
+  for (i = 0; i < kTestMaxNumChannels; i++) {
     ch = voe_base_->CreateChannel();
     MARK();
   }
-  for (i = 0; i < voe_base_->MaxNumOfChannels(); i++) {
+  for (i = 0; i < kTestMaxNumChannels; i++) {
     voe_base_->DeleteChannel(i);
     MARK();
   }
-  for (i = 0; i < voe_base_->MaxNumOfChannels(); i++) {
+  for (i = 0; i < kTestMaxNumChannels; i++) {
     ch = voe_base_->CreateChannel();
     ExtendedTestTransport* ptrTransport =
         new ExtendedTestTransport(voe_network);
@@ -669,17 +661,17 @@ int VoEExtendedTest::TestBase() {
   voe_base_->DeleteChannel(ch);
 
   // Multi-channel tests
-  for (i = 0; i < kVoiceEngineMaxNumChannels; i++) {
+  for (i = 0; i < kTestMaxNumChannels; i++) {
     ch = voe_base_->CreateChannel();
     TEST_MUSTPASS(voe_base_->StartPlayout(ch));
     MARK();
   }
-  for (i = 0; i < kVoiceEngineMaxNumChannels; i++) {
+  for (i = 0; i < kTestMaxNumChannels; i++) {
     TEST_MUSTPASS(voe_base_->StopPlayout(i));
     MARK();
     voe_base_->DeleteChannel(i);
   }
-  for (i = 0; i < kVoiceEngineMaxNumChannels; i++) {
+  for (i = 0; i < kTestMaxNumChannels; i++) {
     ch = voe_base_->CreateChannel();
     TEST_MUSTPASS(voe_base_->StartPlayout(ch));
     MARK();
@@ -791,7 +783,7 @@ int VoEExtendedTest::TestBase() {
   voe_base_->DeleteChannel(ch);
 
   // verify Set/Get for all supported modes and max number of channels
-  for (i = 0; i < voe_base_->MaxNumOfChannels(); i++) {
+  for (i = 0; i < kTestMaxNumChannels; i++) {
     ch = voe_base_->CreateChannel();
 
     // verify Set/Get for all supported modes
@@ -813,7 +805,7 @@ int VoEExtendedTest::TestBase() {
     SleepMs(50);
   }
 
-  for (i = 0; i < voe_base_->MaxNumOfChannels(); i++) {
+  for (i = 0; i < kTestMaxNumChannels; i++) {
     voe_base_->DeleteChannel(i);
   }
 
@@ -1306,10 +1298,9 @@ int VoEExtendedTest::TestCodec() {
   CodecInst defaultCodec;
 
   // check the channel parameter
-  int nMaxChannels(voe_base_->MaxNumOfChannels());
-  TEST_MUSTPASS(-1 != codec->GetSendCodec(nMaxChannels-1, cinst));
+  TEST_MUSTPASS(-1 != codec->GetSendCodec(kTestMaxNumChannels-1, cinst));
   MARK(); // not created
-  TEST_MUSTPASS(-1 != codec->GetSendCodec(nMaxChannels, cinst));
+  TEST_MUSTPASS(-1 != codec->GetSendCodec(kTestMaxNumChannels, cinst));
   MARK(); // out of range
   TEST_MUSTPASS(-1 != codec->GetSendCodec(-1, cinst));
   MARK(); // out of range
@@ -3500,7 +3491,7 @@ int VoEExtendedTest::TestFile() {
   TEST_LOG("StartRecordingCall, record both mic and file in specific"
     " channels \n");
   TEST_LOG("Create maxnumofchannels \n");
-  for (int i = 1; i < voe_base_->MaxNumOfChannels(); i++) {
+  for (int i = 1; i < kTestMaxNumChannels; i++) {
     int ch = voe_base_->CreateChannel();
     TEST_MUSTPASS(ch == -1);
     TEST_MUSTPASS(voe_base_->StopPlayout(ch));
@@ -3573,7 +3564,7 @@ int VoEExtendedTest::TestFile() {
           kFileFormatCompressedFile));
   SleepMs(2500);
   TEST_MUSTPASS(file->StopPlayingFileLocally(0));
-  for (int i = 1; i < voe_base_->MaxNumOfChannels(); i++) {
+  for (int i = 1; i < kTestMaxNumChannels; i++) {
     TEST_MUSTPASS(voe_base_->DeleteChannel(i));
   }
 
diff --git a/voice_engine/test/auto_test/voe_stress_test.cc b/voice_engine/test/auto_test/voe_stress_test.cc
index bd154043..d2c19175 100644
--- a/voice_engine/test/auto_test/voe_stress_test.cc
+++ b/voice_engine/test/auto_test/voe_stress_test.cc
@@ -226,7 +226,7 @@ int VoEStressTest::CreateDeleteChannelsTest() {
   //       Make sure audio is OK after test has finished.
 
   // Set up, start with maxChannels/2 channels
-  const int maxChannels = base->MaxNumOfChannels();
+  const int maxChannels = 100;
   VALIDATE_STRESS(maxChannels < 1); // Should always have at least one channel
   bool* channelState = new bool[maxChannels];
   memset(channelState, 0, maxChannels * sizeof(bool));
diff --git a/voice_engine/transmit_mixer.cc b/voice_engine/transmit_mixer.cc
index c7c1aaed..f5ec7f67 100644
--- a/voice_engine/transmit_mixer.cc
+++ b/voice_engine/transmit_mixer.cc
@@ -305,13 +305,11 @@ TransmitMixer::SetAudioProcessingModule(AudioProcessing* audioProcessingModule)
 }
 
 void TransmitMixer::GetSendCodecInfo(int* max_sample_rate, int* max_channels) {
-  ScopedChannel sc(*_channelManagerPtr);
-  void* iterator = NULL;
-  Channel* channel = sc.GetFirstChannel(iterator);
-
   *max_sample_rate = 8000;
   *max_channels = 1;
-  while (channel != NULL) {
+  for (ChannelManager::Iterator it(_channelManagerPtr); it.IsValid();
+       it.Increment()) {
+    Channel* channel = it.GetChannel();
     if (channel->Sending()) {
       CodecInst codec;
       channel->GetSendCodec(codec);
@@ -321,7 +319,6 @@ void TransmitMixer::GetSendCodecInfo(int* max_sample_rate, int* max_channels) {
                                   std::max(*max_sample_rate, codec.plfreq));
       *max_channels = std::max(*max_channels, codec.channels);
     }
-    channel = sc.GetNextChannel(iterator);
   }
 }
 
@@ -424,11 +421,10 @@ TransmitMixer::DemuxAndMix()
     WEBRTC_TRACE(kTraceStream, kTraceVoice, VoEId(_instanceId, -1),
                  "TransmitMixer::DemuxAndMix()");
 
-    ScopedChannel sc(*_channelManagerPtr);
-    void* iterator(NULL);
-    Channel* channelPtr = sc.GetFirstChannel(iterator);
-    while (channelPtr != NULL)
+    for (ChannelManager::Iterator it(_channelManagerPtr); it.IsValid();
+         it.Increment())
     {
+        Channel* channelPtr = it.GetChannel();
         if (channelPtr->InputIsOnHold())
         {
             channelPtr->UpdateLocalTimeStamp();
@@ -438,7 +434,6 @@ TransmitMixer::DemuxAndMix()
             channelPtr->Demultiplex(_audioFrame);
             channelPtr->PrepareEncodeAndSend(_audioFrame.sample_rate_hz_);
         }
-        channelPtr = sc.GetNextChannel(iterator);
     }
     return 0;
 }
@@ -446,8 +441,8 @@ TransmitMixer::DemuxAndMix()
 void TransmitMixer::DemuxAndMix(const int voe_channels[],
                                 int number_of_voe_channels) {
   for (int i = 0; i < number_of_voe_channels; ++i) {
-    voe::ScopedChannel sc(*_channelManagerPtr, voe_channels[i]);
-    voe::Channel* channel_ptr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _channelManagerPtr->GetChannel(voe_channels[i]);
+    voe::Channel* channel_ptr = ch.channel();
     if (channel_ptr) {
       if (channel_ptr->InputIsOnHold()) {
         channel_ptr->UpdateLocalTimeStamp();
@@ -466,16 +461,14 @@ TransmitMixer::EncodeAndSend()
     WEBRTC_TRACE(kTraceStream, kTraceVoice, VoEId(_instanceId, -1),
                  "TransmitMixer::EncodeAndSend()");
 
-    ScopedChannel sc(*_channelManagerPtr);
-    void* iterator(NULL);
-    Channel* channelPtr = sc.GetFirstChannel(iterator);
-    while (channelPtr != NULL)
+    for (ChannelManager::Iterator it(_channelManagerPtr); it.IsValid();
+         it.Increment())
     {
+        Channel* channelPtr = it.GetChannel();
         if (channelPtr->Sending() && !channelPtr->InputIsOnHold())
         {
             channelPtr->EncodeAndSend();
         }
-        channelPtr = sc.GetNextChannel(iterator);
     }
     return 0;
 }
@@ -483,8 +476,8 @@ TransmitMixer::EncodeAndSend()
 void TransmitMixer::EncodeAndSend(const int voe_channels[],
                                   int number_of_voe_channels) {
   for (int i = 0; i < number_of_voe_channels; ++i) {
-    voe::ScopedChannel sc(*_channelManagerPtr, voe_channels[i]);
-    voe::Channel* channel_ptr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _channelManagerPtr->GetChannel(voe_channels[i]);
+    voe::Channel* channel_ptr = ch.channel();
     if (channel_ptr && channel_ptr->Sending() && !channel_ptr->InputIsOnHold())
       channel_ptr->EncodeAndSend();
   }
diff --git a/voice_engine/voe_audio_processing_impl.cc b/voice_engine/voe_audio_processing_impl.cc
index 430f86dc..a57ede93 100644
--- a/voice_engine/voe_audio_processing_impl.cc
+++ b/voice_engine/voe_audio_processing_impl.cc
@@ -342,8 +342,8 @@ int VoEAudioProcessingImpl::SetRxNsStatus(int channel,
     return -1;
   }
 
-  voe::ScopedChannel sc(_shared->channel_manager(), channel);
-  voe::Channel* channelPtr = sc.ChannelPtr();
+  voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+  voe::Channel* channelPtr = ch.channel();
   if (channelPtr == NULL) {
     _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
         "SetRxNsStatus() failed to locate channel");
@@ -368,8 +368,8 @@ int VoEAudioProcessingImpl::GetRxNsStatus(int channel,
     return -1;
   }
 
-  voe::ScopedChannel sc(_shared->channel_manager(), channel);
-  voe::Channel* channelPtr = sc.ChannelPtr();
+  voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+  voe::Channel* channelPtr = ch.channel();
   if (channelPtr == NULL) {
     _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
         "GetRxNsStatus() failed to locate channel");
@@ -395,8 +395,8 @@ int VoEAudioProcessingImpl::SetRxAgcStatus(int channel,
     return -1;
   }
 
-  voe::ScopedChannel sc(_shared->channel_manager(), channel);
-  voe::Channel* channelPtr = sc.ChannelPtr();
+  voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+  voe::Channel* channelPtr = ch.channel();
   if (channelPtr == NULL) {
     _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
         "SetRxAgcStatus() failed to locate channel");
@@ -421,8 +421,8 @@ int VoEAudioProcessingImpl::GetRxAgcStatus(int channel,
     return -1;
   }
 
-  voe::ScopedChannel sc(_shared->channel_manager(), channel);
-  voe::Channel* channelPtr = sc.ChannelPtr();
+  voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+  voe::Channel* channelPtr = ch.channel();
   if (channelPtr == NULL) {
     _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
         "GetRxAgcStatus() failed to locate channel");
@@ -446,8 +446,8 @@ int VoEAudioProcessingImpl::SetRxAgcConfig(int channel,
     return -1;
   }
 
-  voe::ScopedChannel sc(_shared->channel_manager(), channel);
-  voe::Channel* channelPtr = sc.ChannelPtr();
+  voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+  voe::Channel* channelPtr = ch.channel();
   if (channelPtr == NULL) {
     _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
       "SetRxAgcConfig() failed to locate channel");
@@ -470,8 +470,8 @@ int VoEAudioProcessingImpl::GetRxAgcConfig(int channel, AgcConfig& config) {
     return -1;
   }
 
-  voe::ScopedChannel sc(_shared->channel_manager(), channel);
-  voe::Channel* channelPtr = sc.ChannelPtr();
+  voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+  voe::Channel* channelPtr = ch.channel();
   if (channelPtr == NULL) {
     _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
         "GetRxAgcConfig() failed to locate channel");
@@ -771,8 +771,8 @@ int VoEAudioProcessingImpl::RegisterRxVadObserver(
     _shared->SetLastError(VE_NOT_INITED, kTraceError);
     return -1;
   }
-  voe::ScopedChannel sc(_shared->channel_manager(), channel);
-  voe::Channel* channelPtr = sc.ChannelPtr();
+  voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+  voe::Channel* channelPtr = ch.channel();
   if (channelPtr == NULL) {
     _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
         "RegisterRxVadObserver() failed to locate channel");
@@ -788,8 +788,8 @@ int VoEAudioProcessingImpl::DeRegisterRxVadObserver(int channel) {
     _shared->SetLastError(VE_NOT_INITED, kTraceError);
     return -1;
   }
-  voe::ScopedChannel sc(_shared->channel_manager(), channel);
-  voe::Channel* channelPtr = sc.ChannelPtr();
+  voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+  voe::Channel* channelPtr = ch.channel();
   if (channelPtr == NULL) {
     _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
         "DeRegisterRxVadObserver() failed to locate channel");
@@ -807,8 +807,8 @@ int VoEAudioProcessingImpl::VoiceActivityIndicator(int channel) {
     return -1;
   }
 
-  voe::ScopedChannel sc(_shared->channel_manager(), channel);
-  voe::Channel* channelPtr = sc.ChannelPtr();
+  voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+  voe::Channel* channelPtr = ch.channel();
   if (channelPtr == NULL) {
     _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
         "DeRegisterRxVadObserver() failed to locate channel");
diff --git a/voice_engine/voe_base_impl.cc b/voice_engine/voe_base_impl.cc
index 3dddca56..3b7a193c 100644
--- a/voice_engine/voe_base_impl.cc
+++ b/voice_engine/voe_base_impl.cc
@@ -223,8 +223,9 @@ int VoEBaseImpl::OnDataAvailable(const int voe_channels[],
   // No need to go through the APM, demultiplex the data to each VoE channel,
   // encode and send to the network.
   for (int i = 0; i < number_of_voe_channels; ++i) {
-    voe::ScopedChannel sc(_shared->channel_manager(), voe_channels[i]);
-    voe::Channel* channel_ptr = sc.ChannelPtr();
+    voe::ChannelOwner ch =
+        _shared->channel_manager().GetChannel(voe_channels[i]);
+    voe::Channel* channel_ptr = ch.channel();
     if (!channel_ptr)
       continue;
 
@@ -255,14 +256,12 @@ int VoEBaseImpl::RegisterVoiceEngineObserver(VoiceEngineObserver& observer)
     }
 
     // Register the observer in all active channels
-    voe::ScopedChannel sc(_shared->channel_manager());
-    void* iterator(NULL);
-    voe::Channel* channelPtr = sc.GetFirstChannel(iterator);
-    while (channelPtr != NULL)
-    {
-        channelPtr->RegisterVoiceEngineObserver(observer);
-        channelPtr = sc.GetNextChannel(iterator);
+    for (voe::ChannelManager::Iterator it(&_shared->channel_manager());
+         it.IsValid();
+         it.Increment()) {
+      it.GetChannel()->RegisterVoiceEngineObserver(observer);
     }
+
     _shared->transmit_mixer()->RegisterVoiceEngineObserver(observer);
 
     _voiceEngineObserverPtr = &observer;
@@ -287,13 +286,10 @@ int VoEBaseImpl::DeRegisterVoiceEngineObserver()
     _voiceEngineObserverPtr = NULL;
 
     // Deregister the observer in all active channels
-    voe::ScopedChannel sc(_shared->channel_manager());
-    void* iterator(NULL);
-    voe::Channel* channelPtr = sc.GetFirstChannel(iterator);
-    while (channelPtr != NULL)
-    {
-        channelPtr->DeRegisterVoiceEngineObserver();
-        channelPtr = sc.GetNextChannel(iterator);
+    for (voe::ChannelManager::Iterator it(&_shared->channel_manager());
+         it.IsValid();
+         it.Increment()) {
+      it.GetChannel()->DeRegisterVoiceEngineObserver();
     }
 
     return 0;
@@ -538,18 +534,6 @@ int VoEBaseImpl::Terminate()
     return TerminateInternal();
 }
 
-int VoEBaseImpl::MaxNumOfChannels()
-{
-    WEBRTC_TRACE(kTraceApiCall, kTraceVoice, VoEId(_shared->instance_id(), -1),
-                 "MaxNumOfChannels()");
-    int32_t maxNumOfChannels =
-        _shared->channel_manager().MaxNumOfChannels();
-    WEBRTC_TRACE(kTraceStateInfo, kTraceVoice,
-        VoEId(_shared->instance_id(), -1),
-        "MaxNumOfChannels() => %d", maxNumOfChannels);
-    return (maxNumOfChannels);
-}
-
 int VoEBaseImpl::CreateChannel()
 {
     WEBRTC_TRACE(kTraceApiCall, kTraceVoice, VoEId(_shared->instance_id(), -1),
@@ -562,55 +546,40 @@ int VoEBaseImpl::CreateChannel()
         return -1;
     }
 
-    int32_t channelId = -1;
-
-    if (!_shared->channel_manager().CreateChannel(channelId))
-    {
-        _shared->SetLastError(VE_CHANNEL_NOT_CREATED, kTraceError,
-            "CreateChannel() failed to allocate memory for channel");
-        return -1;
+    voe::ChannelOwner channel_owner =
+        _shared->channel_manager().CreateChannel();
+
+    if (channel_owner.channel()->SetEngineInformation(
+            _shared->statistics(),
+            *_shared->output_mixer(),
+            *_shared->transmit_mixer(),
+            *_shared->process_thread(),
+            *_shared->audio_device(),
+            _voiceEngineObserverPtr,
+            &_callbackCritSect) != 0) {
+      _shared->SetLastError(
+          VE_CHANNEL_NOT_CREATED,
+          kTraceError,
+          "CreateChannel() failed to associate engine and channel."
+          " Destroying channel.");
+      _shared->channel_manager()
+          .DestroyChannel(channel_owner.channel()->ChannelId());
+      return -1;
+    } else if (channel_owner.channel()->Init() != 0) {
+      _shared->SetLastError(
+          VE_CHANNEL_NOT_CREATED,
+          kTraceError,
+          "CreateChannel() failed to initialize channel. Destroying"
+          " channel.");
+      _shared->channel_manager()
+          .DestroyChannel(channel_owner.channel()->ChannelId());
+      return -1;
     }
 
-    bool destroyChannel(false);
-    {
-        voe::ScopedChannel sc(_shared->channel_manager(), channelId);
-        voe::Channel* channelPtr = sc.ChannelPtr();
-        if (channelPtr == NULL)
-        {
-            _shared->SetLastError(VE_CHANNEL_NOT_CREATED, kTraceError,
-                "CreateChannel() failed to allocate memory for channel");
-            return -1;
-        }
-        else if (channelPtr->SetEngineInformation(_shared->statistics(),
-                                                  *_shared->output_mixer(),
-                                                  *_shared->transmit_mixer(),
-                                                  *_shared->process_thread(),
-                                                  *_shared->audio_device(),
-                                                  _voiceEngineObserverPtr,
-                                                  &_callbackCritSect) != 0)
-        {
-            destroyChannel = true;
-            _shared->SetLastError(VE_CHANNEL_NOT_CREATED, kTraceError,
-                "CreateChannel() failed to associate engine and channel."
-                " Destroying channel.");
-        }
-        else if (channelPtr->Init() != 0)
-        {
-            destroyChannel = true;
-            _shared->SetLastError(VE_CHANNEL_NOT_CREATED, kTraceError,
-                "CreateChannel() failed to initialize channel. Destroying"
-                " channel.");
-        }
-    }
-    if (destroyChannel)
-    {
-        _shared->channel_manager().DestroyChannel(channelId);
-        return -1;
-    }
     WEBRTC_TRACE(kTraceStateInfo, kTraceVoice,
         VoEId(_shared->instance_id(), -1),
-        "CreateChannel() => %d", channelId);
-    return channelId;
+        "CreateChannel() => %d", channel_owner.channel()->ChannelId());
+    return channel_owner.channel()->ChannelId();
 }
 
 int VoEBaseImpl::DeleteChannel(int channel)
@@ -626,8 +595,8 @@ int VoEBaseImpl::DeleteChannel(int channel)
     }
 
     {
-        voe::ScopedChannel sc(_shared->channel_manager(), channel);
-        voe::Channel* channelPtr = sc.ChannelPtr();
+        voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+        voe::Channel* channelPtr = ch.channel();
         if (channelPtr == NULL)
         {
             _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -636,12 +605,7 @@ int VoEBaseImpl::DeleteChannel(int channel)
         }
     }
 
-    if (_shared->channel_manager().DestroyChannel(channel) != 0)
-    {
-        _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
-            "DeleteChannel() failed to destroy channel");
-        return -1;
-    }
+    _shared->channel_manager().DestroyChannel(channel);
 
     if (StopSend() != 0)
     {
@@ -666,8 +630,8 @@ int VoEBaseImpl::StartReceive(int channel)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -687,8 +651,8 @@ int VoEBaseImpl::StopReceive(int channel)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -708,8 +672,8 @@ int VoEBaseImpl::StartPlayout(int channel)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -739,8 +703,8 @@ int VoEBaseImpl::StopPlayout(int channel)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -766,8 +730,8 @@ int VoEBaseImpl::StartSend(int channel)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -797,8 +761,8 @@ int VoEBaseImpl::StopSend(int channel)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -943,8 +907,8 @@ int VoEBaseImpl::SetNetEQPlayoutMode(int channel, NetEqModes mode)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -963,8 +927,8 @@ int VoEBaseImpl::GetNetEQPlayoutMode(int channel, NetEqModes& mode)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -984,8 +948,8 @@ int VoEBaseImpl::SetOnHoldStatus(int channel, bool enable, OnHoldModes mode)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -1004,8 +968,8 @@ int VoEBaseImpl::GetOnHoldStatus(int channel, bool& enabled, OnHoldModes& mode)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -1043,47 +1007,21 @@ int32_t VoEBaseImpl::StartPlayout()
     return 0;
 }
 
-int32_t VoEBaseImpl::StopPlayout()
-{
-    WEBRTC_TRACE(kTraceInfo, kTraceVoice, VoEId(_shared->instance_id(), -1),
-                 "VoEBaseImpl::StopPlayout()");
-
-    int32_t numOfChannels = _shared->channel_manager().NumOfChannels();
-    if (numOfChannels <= 0)
-    {
-        return 0;
-    }
-
-    uint16_t nChannelsPlaying(0);
-    int32_t* channelsArray = new int32_t[numOfChannels];
-
-    // Get number of playing channels
-    _shared->channel_manager().GetChannelIds(channelsArray, numOfChannels);
-    for (int i = 0; i < numOfChannels; i++)
-    {
-        voe::ScopedChannel sc(_shared->channel_manager(), channelsArray[i]);
-        voe::Channel* chPtr = sc.ChannelPtr();
-        if (chPtr)
-        {
-            if (chPtr->Playing())
-            {
-                nChannelsPlaying++;
-            }
-        }
-    }
-    delete[] channelsArray;
-
-    // Stop audio-device playing if no channel is playing out
-    if (nChannelsPlaying == 0)
-    {
-        if (_shared->audio_device()->StopPlayout() != 0)
-        {
-            _shared->SetLastError(VE_CANNOT_STOP_PLAYOUT, kTraceError,
-                "StopPlayout() failed to stop playout");
-            return -1;
-        }
+int32_t VoEBaseImpl::StopPlayout() {
+  WEBRTC_TRACE(kTraceInfo,
+               kTraceVoice,
+               VoEId(_shared->instance_id(), -1),
+               "VoEBaseImpl::StopPlayout()");
+  // Stop audio-device playing if no channel is playing out
+  if (_shared->NumOfSendingChannels() == 0) {
+    if (_shared->audio_device()->StopPlayout() != 0) {
+      _shared->SetLastError(VE_CANNOT_STOP_PLAYOUT,
+                            kTraceError,
+                            "StopPlayout() failed to stop playout");
+      return -1;
     }
-    return 0;
+  }
+  return 0;
 }
 
 int32_t VoEBaseImpl::StartSend()
@@ -1142,17 +1080,7 @@ int32_t VoEBaseImpl::TerminateInternal()
                  "VoEBaseImpl::TerminateInternal()");
 
     // Delete any remaining channel objects
-    int32_t numOfChannels = _shared->channel_manager().NumOfChannels();
-    if (numOfChannels > 0)
-    {
-        int32_t* channelsArray = new int32_t[numOfChannels];
-        _shared->channel_manager().GetChannelIds(channelsArray, numOfChannels);
-        for (int i = 0; i < numOfChannels; i++)
-        {
-            DeleteChannel(channelsArray[i]);
-        }
-        delete[] channelsArray;
-    }
+    _shared->channel_manager().DestroyAllChannels();
 
     if (_shared->process_thread())
     {
diff --git a/voice_engine/voe_base_impl.h b/voice_engine/voe_base_impl.h
index b192ca20..6715c360 100644
--- a/voice_engine/voe_base_impl.h
+++ b/voice_engine/voe_base_impl.h
@@ -38,8 +38,6 @@ public:
 
     virtual int Terminate();
 
-    virtual int MaxNumOfChannels();
-
     virtual int CreateChannel();
 
     virtual int DeleteChannel(int channel);
diff --git a/voice_engine/voe_call_report_impl.cc b/voice_engine/voe_call_report_impl.cc
index cf76850d..861354f3 100644
--- a/voice_engine/voe_call_report_impl.cc
+++ b/voice_engine/voe_call_report_impl.cc
@@ -64,6 +64,7 @@ int VoECallReportImpl::ResetCallReportStatistics(int channel)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
+
     assert(_shared->audio_processing() != NULL);
 
     bool echoMode =
@@ -87,8 +88,8 @@ int VoECallReportImpl::ResetCallReportStatistics(int channel)
     // Reset channel dependent statistics
     if (channel != -1)
     {
-        voe::ScopedChannel sc(_shared->channel_manager(), channel);
-        voe::Channel* channelPtr = sc.ChannelPtr();
+        voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+        voe::Channel* channelPtr = ch.channel();
         if (channelPtr == NULL)
         {
             _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -97,28 +98,13 @@ int VoECallReportImpl::ResetCallReportStatistics(int channel)
         }
         channelPtr->ResetDeadOrAliveCounters();
         channelPtr->ResetRTCPStatistics();
-    }
-    else
-    {
-        int32_t numOfChannels =
-            _shared->channel_manager().NumOfChannels();
-        if (numOfChannels <= 0)
-        {
-            return 0;
-        }
-        int32_t* channelsArray = new int32_t[numOfChannels];
-        _shared->channel_manager().GetChannelIds(channelsArray, numOfChannels);
-        for (int i = 0; i < numOfChannels; i++)
-        {
-            voe::ScopedChannel sc(_shared->channel_manager(), channelsArray[i]);
-            voe::Channel* channelPtr = sc.ChannelPtr();
-            if (channelPtr)
-            {
-                channelPtr->ResetDeadOrAliveCounters();
-                channelPtr->ResetRTCPStatistics();
-            }
-        }
-        delete[] channelsArray;
+    } else {
+      for (voe::ChannelManager::Iterator it(&_shared->channel_manager());
+           it.IsValid();
+           it.Increment()) {
+        it.GetChannel()->ResetDeadOrAliveCounters();
+        it.GetChannel()->ResetRTCPStatistics();
+      }
     }
 
     return 0;
@@ -237,8 +223,8 @@ int VoECallReportImpl::GetRoundTripTimeSummary(int channel, StatVal& delaysMs)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -280,8 +266,8 @@ int VoECallReportImpl::GetDeadOrAliveSummaryInternal(int channel,
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -333,48 +319,34 @@ int VoECallReportImpl::WriteReportToFile(const char* fileNameUTF8)
     _file.WriteText("\nNetwork Packet Round Trip Time (RTT)\n");
     _file.WriteText("------------------------------------\n\n");
 
-    int32_t numOfChannels = _shared->channel_manager().NumOfChannels();
-    if (numOfChannels <= 0)
-    {
-        return 0;
-    }
-    int32_t* channelsArray = new int32_t[numOfChannels];
-    _shared->channel_manager().GetChannelIds(channelsArray, numOfChannels);
-    for (int ch = 0; ch < numOfChannels; ch++)
-    {
-        voe::ScopedChannel sc(_shared->channel_manager(), channelsArray[ch]);
-        voe::Channel* channelPtr = sc.ChannelPtr();
-        if (channelPtr)
-        {
-            StatVal delaysMs;
-            _file.WriteText("channel %d:\n", ch);
-            channelPtr->GetRoundTripTimeSummary(delaysMs);
-            _file.WriteText("  min:%5d [ms]\n", delaysMs.min);
-            _file.WriteText("  max:%5d [ms]\n", delaysMs.max);
-            _file.WriteText("  avg:%5d [ms]\n", delaysMs.average);
-        }
+    if (_shared->channel_manager().NumOfChannels() == 0)
+      return 0;
+
+    for (voe::ChannelManager::Iterator it(&_shared->channel_manager());
+         it.IsValid();
+         it.Increment()) {
+      StatVal delaysMs;
+      _file.WriteText("channel %d:\n", it.GetChannel()->ChannelId());
+      it.GetChannel()->GetRoundTripTimeSummary(delaysMs);
+      _file.WriteText("  min:%5d [ms]\n", delaysMs.min);
+      _file.WriteText("  max:%5d [ms]\n", delaysMs.max);
+      _file.WriteText("  avg:%5d [ms]\n", delaysMs.average);
     }
 
     _file.WriteText("\nDead-or-Alive Connection Detections\n");
     _file.WriteText("------------------------------------\n\n");
 
-    for (int ch = 0; ch < numOfChannels; ch++)
-    {
-        voe::ScopedChannel sc(_shared->channel_manager(), channelsArray[ch]);
-        voe::Channel* channelPtr = sc.ChannelPtr();
-        if (channelPtr)
-        {
-            int nDead(0);
-            int nAlive(0);
-            _file.WriteText("channel %d:\n", ch);
-            GetDeadOrAliveSummary(ch, nDead, nAlive);
-            _file.WriteText("  #dead :%6d\n", nDead);
-            _file.WriteText("  #alive:%6d\n", nAlive);
-        }
+    for (voe::ChannelManager::Iterator it(&_shared->channel_manager());
+         it.IsValid();
+         it.Increment()) {
+      int dead = 0;
+      int alive = 0;
+      _file.WriteText("channel %d:\n", it.GetChannel()->ChannelId());
+      GetDeadOrAliveSummary(it.GetChannel()->ChannelId(), dead, alive);
+      _file.WriteText("  #dead :%6d\n", dead);
+      _file.WriteText("  #alive:%6d\n", alive);
     }
 
-    delete[] channelsArray;
-
     EchoStatistics echo;
     GetEchoMetricSummary(echo);
 
diff --git a/voice_engine/voe_codec_impl.cc b/voice_engine/voe_codec_impl.cc
index 6cc791af..3acd2bee 100644
--- a/voice_engine/voe_codec_impl.cc
+++ b/voice_engine/voe_codec_impl.cc
@@ -122,8 +122,8 @@ int VoECodecImpl::SetSendCodec(int channel, const CodecInst& codec)
             "SetSendCodec() invalid number of channels");
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -156,8 +156,8 @@ int VoECodecImpl::GetSendCodec(int channel, CodecInst& codec)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -189,8 +189,8 @@ int VoECodecImpl::GetRecCodec(int channel, CodecInst& codec)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -223,8 +223,8 @@ int VoECodecImpl::SetAMREncFormat(int channel, AmrMode mode)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -249,8 +249,8 @@ int VoECodecImpl::SetAMRDecFormat(int channel, AmrMode mode)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -277,8 +277,8 @@ int VoECodecImpl::SetAMRWbEncFormat(int channel, AmrMode mode)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -305,8 +305,8 @@ int VoECodecImpl::SetAMRWbDecFormat(int channel, AmrMode mode)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -334,8 +334,8 @@ int VoECodecImpl::SetRecPayloadType(int channel, const CodecInst& codec)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -354,8 +354,8 @@ int VoECodecImpl::GetRecPayloadType(int channel, CodecInst& codec)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -392,8 +392,8 @@ int VoECodecImpl::SetSendCNPayloadType(int channel, int type,
             "SetSendCNPayloadType() invalid payload frequency");
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -417,8 +417,8 @@ int VoECodecImpl::SetISACInitTargetRate(int channel, int rateBps,
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -445,8 +445,8 @@ int VoECodecImpl::SetISACMaxRate(int channel, int rateBps)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -474,8 +474,8 @@ int VoECodecImpl::SetISACMaxPayloadSize(int channel, int sizeBytes)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -503,8 +503,8 @@ int VoECodecImpl::SetVADStatus(int channel, bool enable, VadModes mode,
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -542,8 +542,8 @@ int VoECodecImpl::GetVADStatus(int channel, bool& enabled, VadModes& mode,
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -696,8 +696,8 @@ int VoECodecImpl::SetSecondarySendCodec(int channel, const CodecInst& codec,
                           "SetSecondarySendCodec() invalid number of channels");
     return -1;
   }
-  voe::ScopedChannel sc(_shared->channel_manager(), channel);
-  voe::Channel* channelPtr = sc.ChannelPtr();
+  voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+  voe::Channel* channelPtr = ch.channel();
   if (channelPtr == NULL) {
     _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
                           "SetSecondarySendCodec() failed to locate channel");
@@ -724,8 +724,8 @@ int VoECodecImpl::GetSecondarySendCodec(int channel, CodecInst& codec) {
     _shared->SetLastError(VE_NOT_INITED, kTraceError);
     return -1;
   }
-  voe::ScopedChannel sc(_shared->channel_manager(), channel);
-  voe::Channel* channelPtr = sc.ChannelPtr();
+  voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+  voe::Channel* channelPtr = ch.channel();
   if (channelPtr == NULL) {
     _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
                           "GetSecondarySendCodec() failed to locate channel");
@@ -750,8 +750,8 @@ int VoECodecImpl::GetSecondarySendCodec(int channel, CodecInst& codec) {
 int VoECodecImpl::RemoveSecondarySendCodec(int channel) {
   WEBRTC_TRACE(kTraceApiCall, kTraceVoice, VoEId(_shared->instance_id(), -1),
                "RemoveSecondarySendCodec(channel=%d)", channel);
-  voe::ScopedChannel sc(_shared->channel_manager(), channel);
-  voe::Channel* channelPtr = sc.ChannelPtr();
+  voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+  voe::Channel* channelPtr = ch.channel();
   if (channelPtr == NULL) {
     _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
                           "RemoveSecondarySendCodec() failed to locate "
diff --git a/voice_engine/voe_dtmf_impl.cc b/voice_engine/voe_dtmf_impl.cc
index 4d1a7a93..ac2c5466 100644
--- a/voice_engine/voe_dtmf_impl.cc
+++ b/voice_engine/voe_dtmf_impl.cc
@@ -67,8 +67,8 @@ int VoEDtmfImpl::SendTelephoneEvent(int channel,
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -161,8 +161,8 @@ int VoEDtmfImpl::SetSendTelephoneEventPayloadType(int channel,
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -182,8 +182,8 @@ int VoEDtmfImpl::GetSendTelephoneEventPayloadType(int channel,
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -314,8 +314,8 @@ int VoEDtmfImpl::SetDtmfPlayoutStatus(int channel, bool enable)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -335,8 +335,8 @@ int VoEDtmfImpl::GetDtmfPlayoutStatus(int channel, bool& enabled)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
diff --git a/voice_engine/voe_encryption_impl.cc b/voice_engine/voe_encryption_impl.cc
index cf91b961..518a1c61 100644
--- a/voice_engine/voe_encryption_impl.cc
+++ b/voice_engine/voe_encryption_impl.cc
@@ -59,8 +59,8 @@ int VoEEncryptionImpl::RegisterExternalEncryption(int channel,
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -79,8 +79,8 @@ int VoEEncryptionImpl::DeRegisterExternalEncryption(int channel)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
diff --git a/voice_engine/voe_external_media_impl.cc b/voice_engine/voe_external_media_impl.cc
index 531d3bc7..c76c280b 100644
--- a/voice_engine/voe_external_media_impl.cc
+++ b/voice_engine/voe_external_media_impl.cc
@@ -72,8 +72,9 @@ int VoEExternalMediaImpl::RegisterExternalMediaProcessing(
         case kPlaybackPerChannel:
         case kRecordingPerChannel:
         {
-            voe::ScopedChannel sc(shared_->channel_manager(), channel);
-            voe::Channel* channelPtr = sc.ChannelPtr();
+            voe::ChannelOwner ch =
+                shared_->channel_manager().GetChannel(channel);
+            voe::Channel* channelPtr = ch.channel();
             if (channelPtr == NULL)
             {
                 shared_->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -115,8 +116,9 @@ int VoEExternalMediaImpl::DeRegisterExternalMediaProcessing(
         case kPlaybackPerChannel:
         case kRecordingPerChannel:
         {
-            voe::ScopedChannel sc(shared_->channel_manager(), channel);
-            voe::Channel* channelPtr = sc.ChannelPtr();
+            voe::ChannelOwner ch =
+                shared_->channel_manager().GetChannel(channel);
+            voe::Channel* channelPtr = ch.channel();
             if (channelPtr == NULL)
             {
                 shared_->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -349,8 +351,8 @@ int VoEExternalMediaImpl::GetAudioFrame(int channel, int desired_sample_rate_hz,
         shared_->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(shared_->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = shared_->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         shared_->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -387,8 +389,8 @@ int VoEExternalMediaImpl::SetExternalMixing(int channel, bool enable) {
         shared_->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(shared_->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = shared_->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         shared_->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
diff --git a/voice_engine/voe_file_impl.cc b/voice_engine/voe_file_impl.cc
index 0da21622..d8779c81 100644
--- a/voice_engine/voe_file_impl.cc
+++ b/voice_engine/voe_file_impl.cc
@@ -71,8 +71,8 @@ int VoEFileImpl::StartPlayingFileLocally(
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -107,8 +107,8 @@ int VoEFileImpl::StartPlayingFileLocally(int channel,
         return -1;
     }
 
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -133,8 +133,8 @@ int VoEFileImpl::StopPlayingFileLocally(int channel)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -153,8 +153,8 @@ int VoEFileImpl::IsPlayingFileLocally(int channel)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -174,8 +174,8 @@ int VoEFileImpl::ScaleLocalFilePlayout(int channel, float scale)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -234,8 +234,8 @@ int VoEFileImpl::StartPlayingFileAsMicrophone(int channel,
     else
     {
         // Add file after demultiplexing <=> affects one channel only
-        voe::ScopedChannel sc(_shared->channel_manager(), channel);
-        voe::Channel* channelPtr = sc.ChannelPtr();
+        voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+        voe::Channel* channelPtr = ch.channel();
         if (channelPtr == NULL)
         {
             _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -311,8 +311,8 @@ int VoEFileImpl::StartPlayingFileAsMicrophone(int channel,
     else
     {
         // Add file after demultiplexing <=> affects one channel only
-        voe::ScopedChannel sc(_shared->channel_manager(), channel);
-        voe::Channel* channelPtr = sc.ChannelPtr();
+        voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+        voe::Channel* channelPtr = ch.channel();
         if (channelPtr == NULL)
         {
             _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -355,8 +355,8 @@ int VoEFileImpl::StopPlayingFileAsMicrophone(int channel)
     else
     {
         // Stop adding file after demultiplexing <=> affects one channel only
-        voe::ScopedChannel sc(_shared->channel_manager(), channel);
-        voe::Channel* channelPtr = sc.ChannelPtr();
+        voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+        voe::Channel* channelPtr = ch.channel();
         if (channelPtr == NULL)
         {
             _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -383,8 +383,8 @@ int VoEFileImpl::IsPlayingFileAsMicrophone(int channel)
     else
     {
         // Stop adding file after demultiplexing <=> affects one channel only
-        voe::ScopedChannel sc(_shared->channel_manager(), channel);
-        voe::Channel* channelPtr = sc.ChannelPtr();
+        voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+        voe::Channel* channelPtr = ch.channel();
         if (channelPtr == NULL)
         {
             _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -413,8 +413,8 @@ int VoEFileImpl::ScaleFileAsMicrophonePlayout(int channel, float scale)
     else
     {
         // Stop adding file after demultiplexing <=> affects one channel only
-        voe::ScopedChannel sc(_shared->channel_manager(), channel);
-        voe::Channel* channelPtr = sc.ChannelPtr();
+        voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+        voe::Channel* channelPtr = ch.channel();
         if (channelPtr == NULL)
         {
             _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -448,8 +448,8 @@ int VoEFileImpl::StartRecordingPlayout(
     else
     {
         // Add file after demultiplexing <=> affects one channel only
-        voe::ScopedChannel sc(_shared->channel_manager(), channel);
-        voe::Channel* channelPtr = sc.ChannelPtr();
+        voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+        voe::Channel* channelPtr = ch.channel();
         if (channelPtr == NULL)
         {
             _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -478,8 +478,8 @@ int VoEFileImpl::StartRecordingPlayout(
     }
     else
     {
-        voe::ScopedChannel sc(_shared->channel_manager(), channel);
-        voe::Channel* channelPtr = sc.ChannelPtr();
+        voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+        voe::Channel* channelPtr = ch.channel();
         if (channelPtr == NULL)
         {
             _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -505,8 +505,8 @@ int VoEFileImpl::StopRecordingPlayout(int channel)
     }
     else
     {
-        voe::ScopedChannel sc(_shared->channel_manager(), channel);
-        voe::Channel* channelPtr = sc.ChannelPtr();
+        voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+        voe::Channel* channelPtr = ch.channel();
         if (channelPtr == NULL)
         {
             _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -1342,8 +1342,8 @@ int VoEFileImpl::GetPlaybackPosition(int channel, int& positionMs)
     WEBRTC_TRACE(kTraceApiCall, kTraceVoice, VoEId(_shared->instance_id(), -1),
                  "GetPlaybackPosition(channel=%d)", channel);
 
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
diff --git a/voice_engine/voe_neteq_stats_impl.cc b/voice_engine/voe_neteq_stats_impl.cc
index 661c8c65..264f4865 100644
--- a/voice_engine/voe_neteq_stats_impl.cc
+++ b/voice_engine/voe_neteq_stats_impl.cc
@@ -61,8 +61,8 @@ int VoENetEqStatsImpl::GetNetworkStatistics(int channel,
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
diff --git a/voice_engine/voe_network_impl.cc b/voice_engine/voe_network_impl.cc
index 62521706..615fd6a0 100644
--- a/voice_engine/voe_network_impl.cc
+++ b/voice_engine/voe_network_impl.cc
@@ -54,8 +54,8 @@ int VoENetworkImpl::RegisterExternalTransport(int channel,
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -74,8 +74,8 @@ int VoENetworkImpl::DeRegisterExternalTransport(int channel)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -109,8 +109,8 @@ int VoENetworkImpl::ReceivedRTPPacket(int channel,
             "ReceivedRTPPacket() invalid data vector");
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -149,8 +149,8 @@ int VoENetworkImpl::ReceivedRTCPPacket(int channel, const void* data,
             "ReceivedRTCPPacket() invalid data vector");
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -187,8 +187,8 @@ int VoENetworkImpl::SetPacketTimeoutNotification(int channel,
             "SetPacketTimeoutNotification() invalid timeout size");
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -210,8 +210,8 @@ int VoENetworkImpl::GetPacketTimeoutNotification(int channel,
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -233,8 +233,8 @@ int VoENetworkImpl::RegisterDeadOrAliveObserver(int channel,
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -253,8 +253,8 @@ int VoENetworkImpl::DeRegisterDeadOrAliveObserver(int channel)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -284,8 +284,8 @@ int VoENetworkImpl::SetPeriodicDeadOrAliveStatus(int channel, bool enable,
             "SetPeriodicDeadOrAliveStatus() invalid sample time");
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -307,8 +307,8 @@ int VoENetworkImpl::GetPeriodicDeadOrAliveStatus(int channel,
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
diff --git a/voice_engine/voe_rtp_rtcp_impl.cc b/voice_engine/voe_rtp_rtcp_impl.cc
index f4554db2..945c5384 100644
--- a/voice_engine/voe_rtp_rtcp_impl.cc
+++ b/voice_engine/voe_rtp_rtcp_impl.cc
@@ -59,8 +59,8 @@ int VoERTP_RTCPImpl::RegisterRTPObserver(int channel, VoERTPObserver& observer)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -79,8 +79,8 @@ int VoERTP_RTCPImpl::DeRegisterRTPObserver(int channel)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -100,8 +100,8 @@ int VoERTP_RTCPImpl::RegisterRTCPObserver(int channel, VoERTCPObserver& observer
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -120,8 +120,8 @@ int VoERTP_RTCPImpl::DeRegisterRTCPObserver(int channel)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -140,8 +140,8 @@ int VoERTP_RTCPImpl::SetLocalSSRC(int channel, unsigned int ssrc)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -160,8 +160,8 @@ int VoERTP_RTCPImpl::GetLocalSSRC(int channel, unsigned int& ssrc)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -180,8 +180,8 @@ int VoERTP_RTCPImpl::GetRemoteSSRC(int channel, unsigned int& ssrc)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -200,8 +200,8 @@ int VoERTP_RTCPImpl::GetRemoteCSRCs(int channel, unsigned int arrCSRC[15])
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -235,8 +235,8 @@ int VoERTP_RTCPImpl::SetRTPAudioLevelIndicationStatus(int channel,
     }
 
     // Set state and ID for the specified channel.
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -258,8 +258,8 @@ int VoERTP_RTCPImpl::GetRTPAudioLevelIndicationStatus(int channel,
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -278,8 +278,8 @@ int VoERTP_RTCPImpl::SetRTCPStatus(int channel, bool enable)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -298,8 +298,8 @@ int VoERTP_RTCPImpl::GetRTCPStatus(int channel, bool& enabled)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -318,8 +318,8 @@ int VoERTP_RTCPImpl::SetRTCP_CNAME(int channel, const char cName[256])
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -338,8 +338,8 @@ int VoERTP_RTCPImpl::GetRTCP_CNAME(int channel, char cName[256])
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -358,8 +358,8 @@ int VoERTP_RTCPImpl::GetRemoteRTCP_CNAME(int channel, char cName[256])
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -385,8 +385,8 @@ int VoERTP_RTCPImpl::GetRemoteRTCPData(
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -417,8 +417,8 @@ int VoERTP_RTCPImpl::SendApplicationDefinedRTCPPacket(
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -443,8 +443,8 @@ int VoERTP_RTCPImpl::GetRTPStatistics(int channel,
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -465,8 +465,8 @@ int VoERTP_RTCPImpl::GetRTCPStatistics(int channel, CallStatistics& stats)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -484,8 +484,8 @@ int VoERTP_RTCPImpl::GetRemoteRTCPSenderInfo(int channel,
     _shared->SetLastError(VE_NOT_INITED, kTraceError);
     return -1;
   }
-  voe::ScopedChannel sc(_shared->channel_manager(), channel);
-  voe::Channel* channel_ptr = sc.ChannelPtr();
+  voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+  voe::Channel* channel_ptr = ch.channel();
   if (channel_ptr == NULL) {
     _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
         "GetRemoteRTCPSenderInfo() failed to locate channel");
@@ -502,8 +502,8 @@ int VoERTP_RTCPImpl::GetRemoteRTCPReportBlocks(
     _shared->SetLastError(VE_NOT_INITED, kTraceError);
     return -1;
   }
-  voe::ScopedChannel sc(_shared->channel_manager(), channel);
-  voe::Channel* channel_ptr = sc.ChannelPtr();
+  voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+  voe::Channel* channel_ptr = ch.channel();
   if (channel_ptr == NULL) {
     _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
         "GetRemoteRTCPReportBlocks() failed to locate channel");
@@ -523,8 +523,8 @@ int VoERTP_RTCPImpl::SetFECStatus(int channel, bool enable, int redPayloadtype)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -552,8 +552,8 @@ int VoERTP_RTCPImpl::GetFECStatus(int channel,
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -577,8 +577,8 @@ int VoERTP_RTCPImpl::SetNACKStatus(int channel,
                  "SetNACKStatus(channel=%d, enable=%d, maxNoPackets=%d)",
                  channel, enable, maxNoPackets);
 
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -603,8 +603,8 @@ int VoERTP_RTCPImpl::StartRTPDump(int channel,
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -623,8 +623,8 @@ int VoERTP_RTCPImpl::StopRTPDump(int channel, RTPDirections direction)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -644,8 +644,8 @@ int VoERTP_RTCPImpl::RTPDumpIsActive(int channel, RTPDirections direction)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -665,17 +665,18 @@ int VoERTP_RTCPImpl::InsertExtraRTPPacket(int channel,
                  "InsertExtraRTPPacket(channel=%d, payloadType=%u,"
                  " markerBit=%u, payloadSize=%u)",
                  channel, payloadType, markerBit, payloadSize);
+
     if (!_shared->statistics().Initialized())
     {
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
-            "StopRTPDump() failed to locate channel");
+            "InsertExtraRTPPacket() failed to locate channel");
         return -1;
     }
     return channelPtr->InsertExtraRTPPacket(payloadType,
@@ -693,8 +694,8 @@ int VoERTP_RTCPImpl::GetLastRemoteTimeStamp(int channel,
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
diff --git a/voice_engine/voe_video_sync_impl.cc b/voice_engine/voe_video_sync_impl.cc
index 91c07503..5b3312c6 100644
--- a/voice_engine/voe_video_sync_impl.cc
+++ b/voice_engine/voe_video_sync_impl.cc
@@ -58,15 +58,15 @@ int VoEVideoSyncImpl::GetPlayoutTimestamp(int channel, unsigned int& timestamp)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
-    if (channelPtr == NULL)
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channel_ptr = ch.channel();
+    if (channel_ptr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
             "GetPlayoutTimestamp() failed to locate channel");
         return -1;
     }
-    return channelPtr->GetPlayoutTimestamp(timestamp);
+    return channel_ptr->GetPlayoutTimestamp(timestamp);
 }
 
 int VoEVideoSyncImpl::SetInitTimestamp(int channel,
@@ -82,8 +82,8 @@ int VoEVideoSyncImpl::SetInitTimestamp(int channel,
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -106,8 +106,8 @@ int VoEVideoSyncImpl::SetInitSequenceNumber(int channel,
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -129,8 +129,8 @@ int VoEVideoSyncImpl::SetMinimumPlayoutDelay(int channel,int delayMs)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -153,15 +153,15 @@ int VoEVideoSyncImpl::SetInitialPlayoutDelay(int channel, int delay_ms)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channel_ptr = sc.ChannelPtr();
-    if (channel_ptr == NULL)
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
+    if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
             "SetInitialPlayoutDelay() failed to locate channel");
         return -1;
     }
-    return channel_ptr->SetInitialPlayoutDelay(delay_ms);
+    return channelPtr->SetInitialPlayoutDelay(delay_ms);
 }
 
 int VoEVideoSyncImpl::GetDelayEstimate(int channel,
@@ -175,8 +175,8 @@ int VoEVideoSyncImpl::GetDelayEstimate(int channel,
     _shared->SetLastError(VE_NOT_INITED, kTraceError);
     return -1;
   }
-  voe::ScopedChannel sc(_shared->channel_manager(), channel);
-  voe::Channel* channelPtr = sc.ChannelPtr();
+  voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+  voe::Channel* channelPtr = ch.channel();
   if (channelPtr == NULL) {
     _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
                           "GetDelayEstimate() failed to locate channel");
@@ -226,8 +226,8 @@ int VoEVideoSyncImpl::GetRtpRtcp(int channel, RtpRtcp* &rtpRtcpModule)
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -246,8 +246,8 @@ int VoEVideoSyncImpl::GetLeastRequiredDelayMs(int channel) const {
     _shared->SetLastError(VE_NOT_INITED, kTraceError);
     return -1;
   }
-  voe::ScopedChannel sc(_shared->channel_manager(), channel);
-  voe::Channel* channel_ptr = sc.ChannelPtr();
+  voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+  voe::Channel* channel_ptr = ch.channel();
   if (channel_ptr == NULL) {
     _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
                           "GetLeastRequiredDelayMs() failed to locate channel");
diff --git a/voice_engine/voe_volume_control_impl.cc b/voice_engine/voe_volume_control_impl.cc
index c7555fcf..62f709f7 100644
--- a/voice_engine/voe_volume_control_impl.cc
+++ b/voice_engine/voe_volume_control_impl.cc
@@ -297,8 +297,8 @@ int VoEVolumeControlImpl::SetInputMute(int channel, bool enable)
     else
     {
         // Mute after demultiplexing <=> affects one channel only
-        voe::ScopedChannel sc(_shared->channel_manager(), channel);
-        voe::Channel* channelPtr = sc.ChannelPtr();
+        voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+        voe::Channel* channelPtr = ch.channel();
         if (channelPtr == NULL)
         {
             _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -326,8 +326,8 @@ int VoEVolumeControlImpl::GetInputMute(int channel, bool& enabled)
     }
     else
     {
-        voe::ScopedChannel sc(_shared->channel_manager(), channel);
-        voe::Channel* channelPtr = sc.ChannelPtr();
+        voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+        voe::Channel* channelPtr = ch.channel();
         if (channelPtr == NULL)
         {
             _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -422,8 +422,8 @@ int VoEVolumeControlImpl::GetSpeechOutputLevel(int channel,
     }
     else
     {
-        voe::ScopedChannel sc(_shared->channel_manager(), channel);
-        voe::Channel* channelPtr = sc.ChannelPtr();
+        voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+        voe::Channel* channelPtr = ch.channel();
         if (channelPtr == NULL)
         {
             _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -472,8 +472,8 @@ int VoEVolumeControlImpl::GetSpeechOutputLevelFullRange(int channel,
     }
     else
     {
-        voe::ScopedChannel sc(_shared->channel_manager(), channel);
-        voe::Channel* channelPtr = sc.ChannelPtr();
+        voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+        voe::Channel* channelPtr = ch.channel();
         if (channelPtr == NULL)
         {
             _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -503,8 +503,8 @@ int VoEVolumeControlImpl::SetChannelOutputVolumeScaling(int channel,
             "SetChannelOutputVolumeScaling() invalid parameter");
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -524,8 +524,8 @@ int VoEVolumeControlImpl::GetChannelOutputVolumeScaling(int channel,
         _shared->SetLastError(VE_NOT_INITED, kTraceError);
         return -1;
     }
-    voe::ScopedChannel sc(_shared->channel_manager(), channel);
-    voe::Channel* channelPtr = sc.ChannelPtr();
+    voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+    voe::Channel* channelPtr = ch.channel();
     if (channelPtr == NULL)
     {
         _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -577,8 +577,8 @@ int VoEVolumeControlImpl::SetOutputVolumePan(int channel,
     else
     {
         // Per-channel balance (affects the signal before output mixing)
-        voe::ScopedChannel sc(_shared->channel_manager(), channel);
-        voe::Channel* channelPtr = sc.ChannelPtr();
+        voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+        voe::Channel* channelPtr = ch.channel();
         if (channelPtr == NULL)
         {
             _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
@@ -620,8 +620,8 @@ int VoEVolumeControlImpl::GetOutputVolumePan(int channel,
     }
     else
     {
-        voe::ScopedChannel sc(_shared->channel_manager(), channel);
-        voe::Channel* channelPtr = sc.ChannelPtr();
+        voe::ChannelOwner ch = _shared->channel_manager().GetChannel(channel);
+        voe::Channel* channelPtr = ch.channel();
         if (channelPtr == NULL)
         {
             _shared->SetLastError(VE_CHANNEL_NOT_VALID, kTraceError,
diff --git a/voice_engine/voice_engine.gyp b/voice_engine/voice_engine.gyp
index c20a3fcb..23c57da1 100644
--- a/voice_engine/voice_engine.gyp
+++ b/voice_engine/voice_engine.gyp
@@ -57,8 +57,6 @@
         'channel.h',
         'channel_manager.cc',
         'channel_manager.h',
-        'channel_manager_base.cc',
-        'channel_manager_base.h',
         'dtmf_inband.cc',
         'dtmf_inband.h',
         'dtmf_inband_queue.cc',
diff --git a/voice_engine/voice_engine_defines.h b/voice_engine/voice_engine_defines.h
index 2d69979e..2a904c7d 100644
--- a/voice_engine/voice_engine_defines.h
+++ b/voice_engine/voice_engine_defines.h
@@ -27,9 +27,6 @@
 
 namespace webrtc {
 
-// TODO(ajm): There's not really a reason for this limitation. Remove it.
-enum { kVoiceEngineMaxNumChannels = 100 };
-
 // VolumeControl
 enum { kMinVolumeLevel = 0 };
 enum { kMaxVolumeLevel = 255 };