Migrate modules/video_coding to webrtc::Mutex.

Bug: webrtc:11567
Change-Id: I8023fbe7595f7ba8ae7c7db3583fc2e560ec3df2
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/178803
Commit-Queue: Markus Handell <handellm@webrtc.org>
Reviewed-by: Erik Språng <sprang@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#31644}

23 files changed, 190 insertions, 191 deletions

diff --git a/modules/video_coding/BUILD.gn b/modules/video_coding/BUILD.gn
index e92649d4e6..8cb4e7be40 100644
--- a/modules/video_coding/BUILD.gn
+++ b/modules/video_coding/BUILD.gn
@@ -280,6 +280,7 @@ rtc_library("video_coding_legacy") {
     "../../rtc_base:logging",
     "../../rtc_base:rtc_base_approved",
     "../../rtc_base:rtc_event",
+    "../../rtc_base/synchronization:mutex",
     "../../rtc_base/synchronization:sequence_checker",
     "../../system_wrappers",
     "../rtp_rtcp:rtp_rtcp_format",
@@ -437,6 +438,7 @@ rtc_library("webrtc_multiplex") {
     "../../media:rtc_media_base",
     "../../rtc_base",
     "../../rtc_base:checks",
+    "../../rtc_base/synchronization:mutex",
     "../rtp_rtcp:rtp_rtcp_format",
   ]
 }
@@ -572,6 +574,7 @@ rtc_library("webrtc_vp9") {
     "../../rtc_base",
     "../../rtc_base:checks",
     "../../rtc_base/experiments:rate_control_settings",
+    "../../rtc_base/synchronization:mutex",
     "../../system_wrappers:field_trial",
     "../rtp_rtcp:rtp_rtcp_format",
   ]
@@ -707,6 +710,7 @@ if (rtc_include_tests) {
       "../../rtc_base:checks",
       "../../rtc_base:rtc_base_approved",
       "../../rtc_base:rtc_task_queue",
+      "../../rtc_base/synchronization:mutex",
       "../../rtc_base/synchronization:sequence_checker",
       "../../rtc_base/task_utils:to_queued_task",
       "../../test:test_support",
@@ -1001,6 +1005,7 @@ if (rtc_include_tests) {
       "../../rtc_base:rtc_task_queue",
       "../../rtc_base:task_queue_for_test",
       "../../rtc_base/experiments:jitter_upper_bound_experiment",
+      "../../rtc_base/synchronization:mutex",
       "../../system_wrappers",
       "../../system_wrappers:field_trial",
       "../../system_wrappers:metrics",
diff --git a/modules/video_coding/codecs/multiplex/include/multiplex_encoder_adapter.h b/modules/video_coding/codecs/multiplex/include/multiplex_encoder_adapter.h
index 9e718303b7..92a4c88cef 100644
--- a/modules/video_coding/codecs/multiplex/include/multiplex_encoder_adapter.h
+++ b/modules/video_coding/codecs/multiplex/include/multiplex_encoder_adapter.h
@@ -21,7 +21,7 @@
 #include "api/video_codecs/video_encoder_factory.h"
 #include "modules/video_coding/codecs/multiplex/multiplex_encoded_image_packer.h"
 #include "modules/video_coding/include/video_codec_interface.h"
-#include "rtc_base/critical_section.h"
+#include "rtc_base/synchronization/mutex.h"
 
 namespace webrtc {
 
@@ -71,7 +71,7 @@ class MultiplexEncoderAdapter : public VideoEncoder {
   EncodedImageCallback* encoded_complete_callback_;
 
   std::map<uint32_t /* timestamp */, MultiplexImage> stashed_images_
-      RTC_GUARDED_BY(crit_);
+      RTC_GUARDED_BY(mutex_);
 
   uint16_t picture_index_ = 0;
   std::vector<uint8_t> multiplex_dummy_planes_;
@@ -79,7 +79,7 @@ class MultiplexEncoderAdapter : public VideoEncoder {
   int key_frame_interval_;
   EncodedImage combined_image_;
 
-  rtc::CriticalSection crit_;
+  Mutex mutex_;
 
   const bool supports_augmented_data_;
   int augmenting_data_size_ = 0;
diff --git a/modules/video_coding/codecs/multiplex/multiplex_encoder_adapter.cc b/modules/video_coding/codecs/multiplex/multiplex_encoder_adapter.cc
index 492ff19ffa..13f177cdad 100644
--- a/modules/video_coding/codecs/multiplex/multiplex_encoder_adapter.cc
+++ b/modules/video_coding/codecs/multiplex/multiplex_encoder_adapter.cc
@@ -180,7 +180,7 @@ int MultiplexEncoderAdapter::Encode(
   }
 
   {
-    rtc::CritScope cs(&crit_);
+    MutexLock lock(&mutex_);
     stashed_images_.emplace(
         std::piecewise_construct,
         std::forward_as_tuple(input_image.timestamp()),
@@ -273,7 +273,7 @@ int MultiplexEncoderAdapter::Release() {
   }
   encoders_.clear();
   adapter_callbacks_.clear();
-  rtc::CritScope cs(&crit_);
+  MutexLock lock(&mutex_);
   stashed_images_.clear();
 
   return WEBRTC_VIDEO_CODEC_OK;
@@ -298,7 +298,7 @@ EncodedImageCallback::Result MultiplexEncoderAdapter::OnEncodedImage(
   // If we don't already own the buffer, make a copy.
   image_component.encoded_image.Retain();
 
-  rtc::CritScope cs(&crit_);
+  MutexLock lock(&mutex_);
   const auto& stashed_image_itr =
       stashed_images_.find(encodedImage.Timestamp());
   const auto& stashed_image_next_itr = std::next(stashed_image_itr, 1);
diff --git a/modules/video_coding/codecs/test/video_codec_unittest.cc b/modules/video_coding/codecs/test/video_codec_unittest.cc
index c6cf1add94..94806b844e 100644
--- a/modules/video_coding/codecs/test/video_codec_unittest.cc
+++ b/modules/video_coding/codecs/test/video_codec_unittest.cc
@@ -37,7 +37,7 @@ VideoCodecUnitTest::FakeEncodeCompleteCallback::OnEncodedImage(
     const EncodedImage& frame,
     const CodecSpecificInfo* codec_specific_info,
     const RTPFragmentationHeader* fragmentation) {
-  rtc::CritScope lock(&test_->encoded_frame_section_);
+  MutexLock lock(&test_->encoded_frame_section_);
   test_->encoded_frames_.push_back(frame);
   RTC_DCHECK(codec_specific_info);
   test_->codec_specific_infos_.push_back(*codec_specific_info);
@@ -58,7 +58,7 @@ void VideoCodecUnitTest::FakeDecodeCompleteCallback::Decoded(
     VideoFrame& frame,
     absl::optional<int32_t> decode_time_ms,
     absl::optional<uint8_t> qp) {
-  rtc::CritScope lock(&test_->decoded_frame_section_);
+  MutexLock lock(&test_->decoded_frame_section_);
   test_->decoded_frame_.emplace(frame);
   test_->decoded_qp_ = qp;
   test_->decoded_frame_event_.Set();
@@ -126,7 +126,7 @@ bool VideoCodecUnitTest::WaitForEncodedFrame(
 }
 
 void VideoCodecUnitTest::SetWaitForEncodedFramesThreshold(size_t num_frames) {
-  rtc::CritScope lock(&encoded_frame_section_);
+  MutexLock lock(&encoded_frame_section_);
   wait_for_encoded_frames_threshold_ = num_frames;
 }
 
@@ -136,7 +136,7 @@ bool VideoCodecUnitTest::WaitForEncodedFrames(
   EXPECT_TRUE(encoded_frame_event_.Wait(kEncodeTimeoutMs))
       << "Timed out while waiting for encoded frame.";
   // This becomes unsafe if there are multiple threads waiting for frames.
-  rtc::CritScope lock(&encoded_frame_section_);
+  MutexLock lock(&encoded_frame_section_);
   EXPECT_FALSE(encoded_frames_.empty());
   EXPECT_FALSE(codec_specific_infos_.empty());
   EXPECT_EQ(encoded_frames_.size(), codec_specific_infos_.size());
@@ -157,7 +157,7 @@ bool VideoCodecUnitTest::WaitForDecodedFrame(std::unique_ptr<VideoFrame>* frame,
   bool ret = decoded_frame_event_.Wait(kDecodeTimeoutMs);
   EXPECT_TRUE(ret) << "Timed out while waiting for a decoded frame.";
   // This becomes unsafe if there are multiple threads waiting for frames.
-  rtc::CritScope lock(&decoded_frame_section_);
+  MutexLock lock(&decoded_frame_section_);
   EXPECT_TRUE(decoded_frame_);
   if (decoded_frame_) {
     frame->reset(new VideoFrame(std::move(*decoded_frame_)));
@@ -170,7 +170,7 @@ bool VideoCodecUnitTest::WaitForDecodedFrame(std::unique_ptr<VideoFrame>* frame,
 }
 
 size_t VideoCodecUnitTest::GetNumEncodedFrames() {
-  rtc::CritScope lock(&encoded_frame_section_);
+  MutexLock lock(&encoded_frame_section_);
   return encoded_frames_.size();
 }
 
diff --git a/modules/video_coding/codecs/test/video_codec_unittest.h b/modules/video_coding/codecs/test/video_codec_unittest.h
index 1ce37a7ed5..c10eec4cb4 100644
--- a/modules/video_coding/codecs/test/video_codec_unittest.h
+++ b/modules/video_coding/codecs/test/video_codec_unittest.h
@@ -20,8 +20,8 @@
 #include "modules/video_coding/include/video_codec_interface.h"
 #include "modules/video_coding/utility/vp8_header_parser.h"
 #include "modules/video_coding/utility/vp9_uncompressed_header_parser.h"
-#include "rtc_base/critical_section.h"
 #include "rtc_base/event.h"
+#include "rtc_base/synchronization/mutex.h"
 #include "rtc_base/thread_annotations.h"
 #include "test/gtest.h"
 
@@ -108,7 +108,7 @@ class VideoCodecUnitTest : public ::testing::Test {
   FakeDecodeCompleteCallback decode_complete_callback_;
 
   rtc::Event encoded_frame_event_;
-  rtc::CriticalSection encoded_frame_section_;
+  Mutex encoded_frame_section_;
   size_t wait_for_encoded_frames_threshold_;
   std::vector<EncodedImage> encoded_frames_
       RTC_GUARDED_BY(encoded_frame_section_);
@@ -116,7 +116,7 @@ class VideoCodecUnitTest : public ::testing::Test {
       RTC_GUARDED_BY(encoded_frame_section_);
 
   rtc::Event decoded_frame_event_;
-  rtc::CriticalSection decoded_frame_section_;
+  Mutex decoded_frame_section_;
   absl::optional<VideoFrame> decoded_frame_
       RTC_GUARDED_BY(decoded_frame_section_);
   absl::optional<uint8_t> decoded_qp_ RTC_GUARDED_BY(decoded_frame_section_);
diff --git a/modules/video_coding/codecs/vp9/vp9_frame_buffer_pool.cc b/modules/video_coding/codecs/vp9/vp9_frame_buffer_pool.cc
index 551ace22a2..4d0a6983ac 100644
--- a/modules/video_coding/codecs/vp9/vp9_frame_buffer_pool.cc
+++ b/modules/video_coding/codecs/vp9/vp9_frame_buffer_pool.cc
@@ -58,7 +58,7 @@ Vp9FrameBufferPool::GetFrameBuffer(size_t min_size) {
   RTC_DCHECK_GT(min_size, 0);
   rtc::scoped_refptr<Vp9FrameBuffer> available_buffer = nullptr;
   {
-    rtc::CritScope cs(&buffers_lock_);
+    MutexLock lock(&buffers_lock_);
     // Do we have a buffer we can recycle?
     for (const auto& buffer : allocated_buffers_) {
       if (buffer->HasOneRef()) {
@@ -91,7 +91,7 @@ Vp9FrameBufferPool::GetFrameBuffer(size_t min_size) {
 
 int Vp9FrameBufferPool::GetNumBuffersInUse() const {
   int num_buffers_in_use = 0;
-  rtc::CritScope cs(&buffers_lock_);
+  MutexLock lock(&buffers_lock_);
   for (const auto& buffer : allocated_buffers_) {
     if (!buffer->HasOneRef())
       ++num_buffers_in_use;
@@ -100,7 +100,7 @@ int Vp9FrameBufferPool::GetNumBuffersInUse() const {
 }
 
 bool Vp9FrameBufferPool::Resize(size_t max_number_of_buffers) {
-  rtc::CritScope cs(&buffers_lock_);
+  MutexLock lock(&buffers_lock_);
   size_t used_buffers_count = 0;
   for (const auto& buffer : allocated_buffers_) {
     // If the buffer is in use, the ref count will be >= 2, one from the list we
@@ -130,7 +130,7 @@ bool Vp9FrameBufferPool::Resize(size_t max_number_of_buffers) {
 }
 
 void Vp9FrameBufferPool::ClearPool() {
-  rtc::CritScope cs(&buffers_lock_);
+  MutexLock lock(&buffers_lock_);
   allocated_buffers_.clear();
 }
 
diff --git a/modules/video_coding/codecs/vp9/vp9_frame_buffer_pool.h b/modules/video_coding/codecs/vp9/vp9_frame_buffer_pool.h
index 02d2b26273..d37a9fc0e2 100644
--- a/modules/video_coding/codecs/vp9/vp9_frame_buffer_pool.h
+++ b/modules/video_coding/codecs/vp9/vp9_frame_buffer_pool.h
@@ -18,8 +18,8 @@
 
 #include "api/scoped_refptr.h"
 #include "rtc_base/buffer.h"
-#include "rtc_base/critical_section.h"
 #include "rtc_base/ref_count.h"
+#include "rtc_base/synchronization/mutex.h"
 
 struct vpx_codec_ctx;
 struct vpx_codec_frame_buffer;
@@ -119,7 +119,7 @@ class Vp9FrameBufferPool {
 
  private:
   // Protects |allocated_buffers_|.
-  rtc::CriticalSection buffers_lock_;
+  mutable Mutex buffers_lock_;
   // All buffers, in use or ready to be recycled.
   std::vector<rtc::scoped_refptr<Vp9FrameBuffer>> allocated_buffers_
       RTC_GUARDED_BY(buffers_lock_);
diff --git a/modules/video_coding/deprecated/BUILD.gn b/modules/video_coding/deprecated/BUILD.gn
index f333b3f5e2..fd3a5fa5fc 100644
--- a/modules/video_coding/deprecated/BUILD.gn
+++ b/modules/video_coding/deprecated/BUILD.gn
@@ -26,6 +26,7 @@ rtc_library("nack_module") {
     "../../../rtc_base:macromagic",
     "../../../rtc_base:rtc_numerics",
     "../../../rtc_base/experiments:field_trial_parser",
+    "../../../rtc_base/synchronization:mutex",
     "../../../system_wrappers",
     "../../../system_wrappers:field_trial",
     "../../utility",
diff --git a/modules/video_coding/deprecated/nack_module.cc b/modules/video_coding/deprecated/nack_module.cc
index 8658729e99..f8cfd3440b 100644
--- a/modules/video_coding/deprecated/nack_module.cc
+++ b/modules/video_coding/deprecated/nack_module.cc
@@ -115,7 +115,7 @@ int DEPRECATED_NackModule::OnReceivedPacket(uint16_t seq_num,
 int DEPRECATED_NackModule::OnReceivedPacket(uint16_t seq_num,
                                             bool is_keyframe,
                                             bool is_recovered) {
-  rtc::CritScope lock(&crit_);
+  MutexLock lock(&mutex_);
   // TODO(philipel): When the packet includes information whether it is
   //                 retransmitted or not, use that value instead. For
   //                 now set it to true, which will cause the reordering
@@ -184,7 +184,7 @@ int DEPRECATED_NackModule::OnReceivedPacket(uint16_t seq_num,
 }
 
 void DEPRECATED_NackModule::ClearUpTo(uint16_t seq_num) {
-  rtc::CritScope lock(&crit_);
+  MutexLock lock(&mutex_);
   nack_list_.erase(nack_list_.begin(), nack_list_.lower_bound(seq_num));
   keyframe_list_.erase(keyframe_list_.begin(),
                        keyframe_list_.lower_bound(seq_num));
@@ -193,12 +193,12 @@ void DEPRECATED_NackModule::ClearUpTo(uint16_t seq_num) {
 }
 
 void DEPRECATED_NackModule::UpdateRtt(int64_t rtt_ms) {
-  rtc::CritScope lock(&crit_);
+  MutexLock lock(&mutex_);
   rtt_ms_ = rtt_ms;
 }
 
 void DEPRECATED_NackModule::Clear() {
-  rtc::CritScope lock(&crit_);
+  MutexLock lock(&mutex_);
   nack_list_.clear();
   keyframe_list_.clear();
   recovered_list_.clear();
@@ -213,7 +213,7 @@ void DEPRECATED_NackModule::Process() {
   if (nack_sender_) {
     std::vector<uint16_t> nack_batch;
     {
-      rtc::CritScope lock(&crit_);
+      MutexLock lock(&mutex_);
       nack_batch = GetNackBatch(kTimeOnly);
     }
 
diff --git a/modules/video_coding/deprecated/nack_module.h b/modules/video_coding/deprecated/nack_module.h
index d704a05c11..f9580ae80c 100644
--- a/modules/video_coding/deprecated/nack_module.h
+++ b/modules/video_coding/deprecated/nack_module.h
@@ -21,9 +21,9 @@
 #include "modules/include/module.h"
 #include "modules/include/module_common_types.h"
 #include "modules/video_coding/histogram.h"
-#include "rtc_base/critical_section.h"
 #include "rtc_base/deprecation.h"
 #include "rtc_base/numerics/sequence_number_util.h"
+#include "rtc_base/synchronization/mutex.h"
 #include "rtc_base/thread_annotations.h"
 #include "system_wrappers/include/clock.h"
 
@@ -80,24 +80,24 @@ class DEPRECATED_NackModule : public Module {
   };
 
   void AddPacketsToNack(uint16_t seq_num_start, uint16_t seq_num_end)
-      RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_);
+      RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
 
   // Removes packets from the nack list until the next keyframe. Returns true
   // if packets were removed.
-  bool RemovePacketsUntilKeyFrame() RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_);
+  bool RemovePacketsUntilKeyFrame() RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
   std::vector<uint16_t> GetNackBatch(NackFilterOptions options)
-      RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_);
+      RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
 
   // Update the reordering distribution.
   void UpdateReorderingStatistics(uint16_t seq_num)
-      RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_);
+      RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
 
   // Returns how many packets we have to wait in order to receive the packet
   // with probability |probabilty| or higher.
   int WaitNumberOfPackets(float probability) const
-      RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_);
+      RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
 
-  rtc::CriticalSection crit_;
+  Mutex mutex_;
   Clock* const clock_;
   NackSender* const nack_sender_;
   KeyFrameRequestSender* const keyframe_request_sender_;
@@ -106,15 +106,15 @@ class DEPRECATED_NackModule : public Module {
   // known thread (e.g. see |initialized_|). Those probably do not need
   // synchronized access.
   std::map<uint16_t, NackInfo, DescendingSeqNumComp<uint16_t>> nack_list_
-      RTC_GUARDED_BY(crit_);
+      RTC_GUARDED_BY(mutex_);
   std::set<uint16_t, DescendingSeqNumComp<uint16_t>> keyframe_list_
-      RTC_GUARDED_BY(crit_);
+      RTC_GUARDED_BY(mutex_);
   std::set<uint16_t, DescendingSeqNumComp<uint16_t>> recovered_list_
-      RTC_GUARDED_BY(crit_);
-  video_coding::Histogram reordering_histogram_ RTC_GUARDED_BY(crit_);
-  bool initialized_ RTC_GUARDED_BY(crit_);
-  int64_t rtt_ms_ RTC_GUARDED_BY(crit_);
-  uint16_t newest_seq_num_ RTC_GUARDED_BY(crit_);
+      RTC_GUARDED_BY(mutex_);
+  video_coding::Histogram reordering_histogram_ RTC_GUARDED_BY(mutex_);
+  bool initialized_ RTC_GUARDED_BY(mutex_);
+  int64_t rtt_ms_ RTC_GUARDED_BY(mutex_);
+  uint16_t newest_seq_num_ RTC_GUARDED_BY(mutex_);
 
   // Only touched on the process thread.
   int64_t next_process_time_ms_;
diff --git a/modules/video_coding/fec_controller_default.cc b/modules/video_coding/fec_controller_default.cc
index 97919f5315..827c853541 100644
--- a/modules/video_coding/fec_controller_default.cc
+++ b/modules/video_coding/fec_controller_default.cc
@@ -20,7 +20,6 @@
 #include "system_wrappers/include/field_trial.h"
 
 namespace webrtc {
-using rtc::CritScope;
 
 const float kProtectionOverheadRateThreshold = 0.5;
 
@@ -54,7 +53,7 @@ void FecControllerDefault::SetEncodingData(size_t width,
                                            size_t height,
                                            size_t num_temporal_layers,
                                            size_t max_payload_size) {
-  CritScope lock(&crit_sect_);
+  MutexLock lock(&mutex_);
   loss_prot_logic_->UpdateFrameSize(width, height);
   loss_prot_logic_->UpdateNumLayers(num_temporal_layers);
   max_payload_size_ = max_payload_size;
@@ -94,7 +93,7 @@ uint32_t FecControllerDefault::UpdateFecRates(
   FecProtectionParams delta_fec_params;
   FecProtectionParams key_fec_params;
   {
-    CritScope lock(&crit_sect_);
+    MutexLock lock(&mutex_);
     loss_prot_logic_->UpdateBitRate(target_bitrate_kbps);
     loss_prot_logic_->UpdateRtt(round_trip_time_ms);
     // Update frame rate for the loss protection logic class: frame rate should
@@ -175,7 +174,7 @@ void FecControllerDefault::SetProtectionMethod(bool enable_fec,
   } else if (enable_fec) {
     method = media_optimization::kFec;
   }
-  CritScope lock(&crit_sect_);
+  MutexLock lock(&mutex_);
   loss_prot_logic_->SetMethod(method);
 }
 
@@ -183,7 +182,7 @@ void FecControllerDefault::UpdateWithEncodedData(
     const size_t encoded_image_length,
     const VideoFrameType encoded_image_frametype) {
   const size_t encoded_length = encoded_image_length;
-  CritScope lock(&crit_sect_);
+  MutexLock lock(&mutex_);
   if (encoded_length > 0) {
     const bool delta_frame =
         encoded_image_frametype != VideoFrameType::kVideoFrameKey;
diff --git a/modules/video_coding/fec_controller_default.h b/modules/video_coding/fec_controller_default.h
index 02c0ec0d37..6b9e8eb8e5 100644
--- a/modules/video_coding/fec_controller_default.h
+++ b/modules/video_coding/fec_controller_default.h
@@ -20,7 +20,7 @@
 #include "api/fec_controller.h"
 #include "modules/video_coding/media_opt_util.h"
 #include "rtc_base/constructor_magic.h"
-#include "rtc_base/critical_section.h"
+#include "rtc_base/synchronization/mutex.h"
 #include "rtc_base/thread_annotations.h"
 #include "system_wrappers/include/clock.h"
 
@@ -54,10 +54,10 @@ class FecControllerDefault : public FecController {
   enum { kBitrateAverageWinMs = 1000 };
   Clock* const clock_;
   VCMProtectionCallback* protection_callback_;
-  rtc::CriticalSection crit_sect_;
+  Mutex mutex_;
   std::unique_ptr<media_optimization::VCMLossProtectionLogic> loss_prot_logic_
-      RTC_GUARDED_BY(crit_sect_);
-  size_t max_payload_size_ RTC_GUARDED_BY(crit_sect_);
+      RTC_GUARDED_BY(mutex_);
+  size_t max_payload_size_ RTC_GUARDED_BY(mutex_);
   RTC_DISALLOW_COPY_AND_ASSIGN(FecControllerDefault);
   const float overhead_threshold_;
 };
diff --git a/modules/video_coding/frame_buffer2.cc b/modules/video_coding/frame_buffer2.cc
index 64d3699e01..88ac09c496 100644
--- a/modules/video_coding/frame_buffer2.cc
+++ b/modules/video_coding/frame_buffer2.cc
@@ -82,7 +82,7 @@ void FrameBuffer::NextFrame(
   int64_t latest_return_time_ms =
       clock_->TimeInMilliseconds() + max_wait_time_ms;
 
-  rtc::CritScope lock(&crit_);
+  MutexLock lock(&mutex_);
   if (stopped_) {
     return;
   }
@@ -102,7 +102,7 @@ void FrameBuffer::StartWaitForNextFrameOnQueue() {
         RTC_DCHECK_RUN_ON(&callback_checker_);
         // If this task has not been cancelled, we did not get any new frames
         // while waiting. Continue with frame delivery.
-        rtc::CritScope lock(&crit_);
+        MutexLock lock(&mutex_);
         if (!frames_to_decode_.empty()) {
           // We have frames, deliver!
           frame_handler_(absl::WrapUnique(GetNextFrame()), kFrameFound);
@@ -329,19 +329,19 @@ bool FrameBuffer::HasBadRenderTiming(const EncodedFrame& frame,
 
 void FrameBuffer::SetProtectionMode(VCMVideoProtection mode) {
   TRACE_EVENT0("webrtc", "FrameBuffer::SetProtectionMode");
-  rtc::CritScope lock(&crit_);
+  MutexLock lock(&mutex_);
   protection_mode_ = mode;
 }
 
 void FrameBuffer::Start() {
   TRACE_EVENT0("webrtc", "FrameBuffer::Start");
-  rtc::CritScope lock(&crit_);
+  MutexLock lock(&mutex_);
   stopped_ = false;
 }
 
 void FrameBuffer::Stop() {
   TRACE_EVENT0("webrtc", "FrameBuffer::Stop");
-  rtc::CritScope lock(&crit_);
+  MutexLock lock(&mutex_);
   if (stopped_)
     return;
   stopped_ = true;
@@ -350,12 +350,12 @@ void FrameBuffer::Stop() {
 }
 
 void FrameBuffer::Clear() {
-  rtc::CritScope lock(&crit_);
+  MutexLock lock(&mutex_);
   ClearFramesAndHistory();
 }
 
 void FrameBuffer::UpdateRtt(int64_t rtt_ms) {
-  rtc::CritScope lock(&crit_);
+  MutexLock lock(&mutex_);
   jitter_estimator_.UpdateRtt(rtt_ms);
 }
 
@@ -431,7 +431,7 @@ int64_t FrameBuffer::InsertFrame(std::unique_ptr<EncodedFrame> frame) {
   TRACE_EVENT0("webrtc", "FrameBuffer::InsertFrame");
   RTC_DCHECK(frame);
 
-  rtc::CritScope lock(&crit_);
+  MutexLock lock(&mutex_);
 
   const VideoLayerFrameId& id = frame->id;
   int64_t last_continuous_picture_id =
@@ -529,7 +529,7 @@ int64_t FrameBuffer::InsertFrame(std::unique_ptr<EncodedFrame> frame) {
     // to return from NextFrame.
     if (callback_queue_) {
       callback_queue_->PostTask([this] {
-        rtc::CritScope lock(&crit_);
+        MutexLock lock(&mutex_);
         if (!callback_task_.Running())
           return;
         RTC_CHECK(frame_handler_);
diff --git a/modules/video_coding/frame_buffer2.h b/modules/video_coding/frame_buffer2.h
index d824ddf4d0..7909000a22 100644
--- a/modules/video_coding/frame_buffer2.h
+++ b/modules/video_coding/frame_buffer2.h
@@ -24,10 +24,10 @@
 #include "modules/video_coding/jitter_estimator.h"
 #include "modules/video_coding/utility/decoded_frames_history.h"
 #include "rtc_base/constructor_magic.h"
-#include "rtc_base/critical_section.h"
 #include "rtc_base/event.h"
 #include "rtc_base/experiments/rtt_mult_experiment.h"
 #include "rtc_base/numerics/sequence_number_util.h"
+#include "rtc_base/synchronization/mutex.h"
 #include "rtc_base/synchronization/sequence_checker.h"
 #include "rtc_base/task_queue.h"
 #include "rtc_base/task_utils/repeating_task.h"
@@ -118,40 +118,40 @@ class FrameBuffer {
   // Check that the references of |frame| are valid.
   bool ValidReferences(const EncodedFrame& frame) const;
 
-  int64_t FindNextFrame(int64_t now_ms) RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_);
-  EncodedFrame* GetNextFrame() RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_);
+  int64_t FindNextFrame(int64_t now_ms) RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
+  EncodedFrame* GetNextFrame() RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
 
-  void StartWaitForNextFrameOnQueue() RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_);
-  void CancelCallback() RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_);
+  void StartWaitForNextFrameOnQueue() RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
+  void CancelCallback() RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
 
   // Update all directly dependent and indirectly dependent frames and mark
   // them as continuous if all their references has been fulfilled.
   void PropagateContinuity(FrameMap::iterator start)
-      RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_);
+      RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
 
   // Marks the frame as decoded and updates all directly dependent frames.
   void PropagateDecodability(const FrameInfo& info)
-      RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_);
+      RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
 
   // Update the corresponding FrameInfo of |frame| and all FrameInfos that
   // |frame| references.
   // Return false if |frame| will never be decodable, true otherwise.
   bool UpdateFrameInfoWithIncomingFrame(const EncodedFrame& frame,
                                         FrameMap::iterator info)
-      RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_);
+      RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
 
-  void UpdateJitterDelay() RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_);
+  void UpdateJitterDelay() RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
 
-  void UpdateTimingFrameInfo() RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_);
+  void UpdateTimingFrameInfo() RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
 
-  void ClearFramesAndHistory() RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_);
+  void ClearFramesAndHistory() RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
 
   // Checks if the superframe, which current frame belongs to, is complete.
   bool IsCompleteSuperFrame(const EncodedFrame& frame)
-      RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_);
+      RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
 
   bool HasBadRenderTiming(const EncodedFrame& frame, int64_t now_ms)
-      RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_);
+      RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
 
   // The cleaner solution would be to have the NextFrame function return a
   // vector of frames, but until the decoding pipeline can support decoding
@@ -164,29 +164,29 @@ class FrameBuffer {
   SequenceChecker callback_checker_;
 
   // Stores only undecoded frames.
-  FrameMap frames_ RTC_GUARDED_BY(crit_);
-  DecodedFramesHistory decoded_frames_history_ RTC_GUARDED_BY(crit_);
+  FrameMap frames_ RTC_GUARDED_BY(mutex_);
+  DecodedFramesHistory decoded_frames_history_ RTC_GUARDED_BY(mutex_);
 
-  rtc::CriticalSection crit_;
+  Mutex mutex_;
   Clock* const clock_;
 
-  rtc::TaskQueue* callback_queue_ RTC_GUARDED_BY(crit_);
-  RepeatingTaskHandle callback_task_ RTC_GUARDED_BY(crit_);
+  rtc::TaskQueue* callback_queue_ RTC_GUARDED_BY(mutex_);
+  RepeatingTaskHandle callback_task_ RTC_GUARDED_BY(mutex_);
   std::function<void(std::unique_ptr<EncodedFrame>, ReturnReason)>
-      frame_handler_ RTC_GUARDED_BY(crit_);
-  int64_t latest_return_time_ms_ RTC_GUARDED_BY(crit_);
-  bool keyframe_required_ RTC_GUARDED_BY(crit_);
+      frame_handler_ RTC_GUARDED_BY(mutex_);
+  int64_t latest_return_time_ms_ RTC_GUARDED_BY(mutex_);
+  bool keyframe_required_ RTC_GUARDED_BY(mutex_);
 
-  VCMJitterEstimator jitter_estimator_ RTC_GUARDED_BY(crit_);
-  VCMTiming* const timing_ RTC_GUARDED_BY(crit_);
-  VCMInterFrameDelay inter_frame_delay_ RTC_GUARDED_BY(crit_);
+  VCMJitterEstimator jitter_estimator_ RTC_GUARDED_BY(mutex_);
+  VCMTiming* const timing_ RTC_GUARDED_BY(mutex_);
+  VCMInterFrameDelay inter_frame_delay_ RTC_GUARDED_BY(mutex_);
   absl::optional<VideoLayerFrameId> last_continuous_frame_
-      RTC_GUARDED_BY(crit_);
-  std::vector<FrameMap::iterator> frames_to_decode_ RTC_GUARDED_BY(crit_);
-  bool stopped_ RTC_GUARDED_BY(crit_);
-  VCMVideoProtection protection_mode_ RTC_GUARDED_BY(crit_);
+      RTC_GUARDED_BY(mutex_);
+  std::vector<FrameMap::iterator> frames_to_decode_ RTC_GUARDED_BY(mutex_);
+  bool stopped_ RTC_GUARDED_BY(mutex_);
+  VCMVideoProtection protection_mode_ RTC_GUARDED_BY(mutex_);
   VCMReceiveStatisticsCallback* const stats_callback_;
-  int64_t last_log_non_decoded_ms_ RTC_GUARDED_BY(crit_);
+  int64_t last_log_non_decoded_ms_ RTC_GUARDED_BY(mutex_);
 
   const bool add_rtt_to_playout_delay_;
 
diff --git a/modules/video_coding/generic_decoder.cc b/modules/video_coding/generic_decoder.cc
index cfe16ed3f1..50ecd8da8d 100644
--- a/modules/video_coding/generic_decoder.cc
+++ b/modules/video_coding/generic_decoder.cc
@@ -86,7 +86,7 @@ void VCMDecodedFrameCallback::Decoded(VideoFrame& decodedImage,
   // callbacks from one call to Decode().
   VCMFrameInformation* frameInfo;
   {
-    rtc::CritScope cs(&lock_);
+    MutexLock lock(&lock_);
     frameInfo = _timestampMap.Pop(decodedImage.timestamp());
   }
 
@@ -172,12 +172,12 @@ void VCMDecodedFrameCallback::OnDecoderImplementationName(
 
 void VCMDecodedFrameCallback::Map(uint32_t timestamp,
                                   VCMFrameInformation* frameInfo) {
-  rtc::CritScope cs(&lock_);
+  MutexLock lock(&lock_);
   _timestampMap.Add(timestamp, frameInfo);
 }
 
 int32_t VCMDecodedFrameCallback::Pop(uint32_t timestamp) {
-  rtc::CritScope cs(&lock_);
+  MutexLock lock(&lock_);
   if (_timestampMap.Pop(timestamp) == NULL) {
     return VCM_GENERAL_ERROR;
   }
diff --git a/modules/video_coding/generic_decoder.h b/modules/video_coding/generic_decoder.h
index 40fe667d65..b89d3f4368 100644
--- a/modules/video_coding/generic_decoder.h
+++ b/modules/video_coding/generic_decoder.h
@@ -19,8 +19,8 @@
 #include "modules/video_coding/include/video_codec_interface.h"
 #include "modules/video_coding/timestamp_map.h"
 #include "modules/video_coding/timing.h"
-#include "rtc_base/critical_section.h"
 #include "rtc_base/experiments/field_trial_parser.h"
+#include "rtc_base/synchronization/mutex.h"
 #include "rtc_base/thread_checker.h"
 
 namespace webrtc {
@@ -70,7 +70,7 @@ class VCMDecodedFrameCallback : public DecodedImageCallback {
   // from the same thread, and therfore a lock is not required to access it.
   VCMReceiveCallback* _receiveCallback = nullptr;
   VCMTiming* _timing;
-  rtc::CriticalSection lock_;
+  Mutex lock_;
   VCMTimestampMap _timestampMap RTC_GUARDED_BY(lock_);
   int64_t ntp_offset_;
   // Set by the field trial WebRTC-SlowDownDecoder to simulate a slow decoder.
diff --git a/modules/video_coding/generic_decoder_unittest.cc b/modules/video_coding/generic_decoder_unittest.cc
index 3e07a2a81c..dbceb187be 100644
--- a/modules/video_coding/generic_decoder_unittest.cc
+++ b/modules/video_coding/generic_decoder_unittest.cc
@@ -16,8 +16,8 @@
 #include "api/task_queue/default_task_queue_factory.h"
 #include "common_video/test/utilities.h"
 #include "modules/video_coding/timing.h"
-#include "rtc_base/critical_section.h"
 #include "rtc_base/event.h"
+#include "rtc_base/synchronization/mutex.h"
 #include "system_wrappers/include/clock.h"
 #include "test/fake_decoder.h"
 #include "test/gmock.h"
@@ -33,7 +33,7 @@ class ReceiveCallback : public VCMReceiveCallback {
                         int32_t decode_time_ms,
                         VideoContentType content_type) override {
     {
-      rtc::CritScope cs(&lock_);
+      MutexLock lock(&lock_);
       last_frame_ = videoFrame;
     }
     received_frame_event_.Set();
@@ -41,13 +41,13 @@ class ReceiveCallback : public VCMReceiveCallback {
   }
 
   absl::optional<VideoFrame> GetLastFrame() {
-    rtc::CritScope cs(&lock_);
+    MutexLock lock(&lock_);
     return last_frame_;
   }
 
   absl::optional<VideoFrame> WaitForFrame(int64_t wait_ms) {
     if (received_frame_event_.Wait(wait_ms)) {
-      rtc::CritScope cs(&lock_);
+      MutexLock lock(&lock_);
       return last_frame_;
     } else {
       return absl::nullopt;
@@ -55,7 +55,7 @@ class ReceiveCallback : public VCMReceiveCallback {
   }
 
  private:
-  rtc::CriticalSection lock_;
+  Mutex lock_;
   rtc::Event received_frame_event_;
   absl::optional<VideoFrame> last_frame_ RTC_GUARDED_BY(lock_);
 };
diff --git a/modules/video_coding/jitter_buffer.cc b/modules/video_coding/jitter_buffer.cc
index 0873285f39..9d2d3a2d1d 100644
--- a/modules/video_coding/jitter_buffer.cc
+++ b/modules/video_coding/jitter_buffer.cc
@@ -153,7 +153,7 @@ VCMJitterBuffer::~VCMJitterBuffer() {
 }
 
 void VCMJitterBuffer::Start() {
-  rtc::CritScope cs(&crit_sect_);
+  MutexLock lock(&mutex_);
   running_ = true;
 
   num_consecutive_old_packets_ = 0;
@@ -172,7 +172,7 @@ void VCMJitterBuffer::Start() {
 }
 
 void VCMJitterBuffer::Stop() {
-  rtc::CritScope cs(&crit_sect_);
+  MutexLock lock(&mutex_);
   running_ = false;
   last_decoded_state_.Reset();
 
@@ -181,12 +181,12 @@ void VCMJitterBuffer::Stop() {
 }
 
 bool VCMJitterBuffer::Running() const {
-  rtc::CritScope cs(&crit_sect_);
+  MutexLock lock(&mutex_);
   return running_;
 }
 
 void VCMJitterBuffer::Flush() {
-  rtc::CritScope cs(&crit_sect_);
+  MutexLock lock(&mutex_);
   decodable_frames_.Reset(&free_frames_);
   incomplete_frames_.Reset(&free_frames_);
   last_decoded_state_.Reset();  // TODO(mikhal): sync reset.
@@ -202,21 +202,20 @@ void VCMJitterBuffer::Flush() {
 }
 
 int VCMJitterBuffer::num_packets() const {
-  rtc::CritScope cs(&crit_sect_);
+  MutexLock lock(&mutex_);
   return num_packets_;
 }
 
 int VCMJitterBuffer::num_duplicated_packets() const {
-  rtc::CritScope cs(&crit_sect_);
+  MutexLock lock(&mutex_);
   return num_duplicated_packets_;
 }
 
 // Returns immediately or a |max_wait_time_ms| ms event hang waiting for a
 // complete frame, |max_wait_time_ms| decided by caller.
 VCMEncodedFrame* VCMJitterBuffer::NextCompleteFrame(uint32_t max_wait_time_ms) {
-  crit_sect_.Enter();
+  MutexLock lock(&mutex_);
   if (!running_) {
-    crit_sect_.Leave();
     return nullptr;
   }
   CleanUpOldOrEmptyFrames();
@@ -227,14 +226,13 @@ VCMEncodedFrame* VCMJitterBuffer::NextCompleteFrame(uint32_t max_wait_time_ms) {
         clock_->TimeInMilliseconds() + max_wait_time_ms;
     int64_t wait_time_ms = max_wait_time_ms;
     while (wait_time_ms > 0) {
-      crit_sect_.Leave();
+      mutex_.Unlock();
       const EventTypeWrapper ret =
           frame_event_->Wait(static_cast<uint32_t>(wait_time_ms));
-      crit_sect_.Enter();
+      mutex_.Lock();
       if (ret == kEventSignaled) {
         // Are we shutting down the jitter buffer?
         if (!running_) {
-          crit_sect_.Leave();
           return nullptr;
         }
         // Finding oldest frame ready for decoder.
@@ -252,16 +250,13 @@ VCMEncodedFrame* VCMJitterBuffer::NextCompleteFrame(uint32_t max_wait_time_ms) {
   }
   if (decodable_frames_.empty() ||
       decodable_frames_.Front()->GetState() != kStateComplete) {
-    crit_sect_.Leave();
     return nullptr;
   }
-  VCMEncodedFrame* encoded_frame = decodable_frames_.Front();
-  crit_sect_.Leave();
-  return encoded_frame;
+  return decodable_frames_.Front();
 }
 
 VCMEncodedFrame* VCMJitterBuffer::ExtractAndSetDecode(uint32_t timestamp) {
-  rtc::CritScope cs(&crit_sect_);
+  MutexLock lock(&mutex_);
   if (!running_) {
     return NULL;
   }
@@ -313,7 +308,7 @@ VCMEncodedFrame* VCMJitterBuffer::ExtractAndSetDecode(uint32_t timestamp) {
 // frames from within the jitter buffer.
 void VCMJitterBuffer::ReleaseFrame(VCMEncodedFrame* frame) {
   RTC_CHECK(frame != nullptr);
-  rtc::CritScope cs(&crit_sect_);
+  MutexLock lock(&mutex_);
   VCMFrameBuffer* frame_buffer = static_cast<VCMFrameBuffer*>(frame);
   RecycleFrameBuffer(frame_buffer);
 }
@@ -354,7 +349,7 @@ VCMFrameBufferEnum VCMJitterBuffer::GetFrame(const VCMPacket& packet,
 int64_t VCMJitterBuffer::LastPacketTime(const VCMEncodedFrame* frame,
                                         bool* retransmitted) const {
   assert(retransmitted);
-  rtc::CritScope cs(&crit_sect_);
+  MutexLock lock(&mutex_);
   const VCMFrameBuffer* frame_buffer =
       static_cast<const VCMFrameBuffer*>(frame);
   *retransmitted = (frame_buffer->GetNackCount() > 0);
@@ -363,7 +358,7 @@ int64_t VCMJitterBuffer::LastPacketTime(const VCMEncodedFrame* frame,
 
 VCMFrameBufferEnum VCMJitterBuffer::InsertPacket(const VCMPacket& packet,
                                                  bool* retransmitted) {
-  rtc::CritScope cs(&crit_sect_);
+  MutexLock lock(&mutex_);
 
   ++num_packets_;
   // Does this packet belong to an old frame?
@@ -577,7 +572,7 @@ void VCMJitterBuffer::FindAndInsertContinuousFramesWithState(
 }
 
 uint32_t VCMJitterBuffer::EstimatedJitterMs() {
-  rtc::CritScope cs(&crit_sect_);
+  MutexLock lock(&mutex_);
   const double rtt_mult = 1.0f;
   return jitter_estimate_.GetJitterEstimate(rtt_mult, absl::nullopt);
 }
@@ -585,7 +580,7 @@ uint32_t VCMJitterBuffer::EstimatedJitterMs() {
 void VCMJitterBuffer::SetNackSettings(size_t max_nack_list_size,
                                       int max_packet_age_to_nack,
                                       int max_incomplete_time_ms) {
-  rtc::CritScope cs(&crit_sect_);
+  MutexLock lock(&mutex_);
   assert(max_packet_age_to_nack >= 0);
   assert(max_incomplete_time_ms_ >= 0);
   max_nack_list_size_ = max_nack_list_size;
@@ -616,7 +611,7 @@ uint16_t VCMJitterBuffer::EstimatedLowSequenceNumber(
 }
 
 std::vector<uint16_t> VCMJitterBuffer::GetNackList(bool* request_key_frame) {
-  rtc::CritScope cs(&crit_sect_);
+  MutexLock lock(&mutex_);
   *request_key_frame = false;
   if (last_decoded_state_.in_initial_state()) {
     VCMFrameBuffer* next_frame = NextFrame();
@@ -827,7 +822,7 @@ void VCMJitterBuffer::UpdateAveragePacketsPerFrame(int current_number_packets) {
   }
 }
 
-// Must be called under the critical section |crit_sect_|.
+// Must be called under the critical section |mutex_|.
 void VCMJitterBuffer::CleanUpOldOrEmptyFrames() {
   decodable_frames_.CleanUpOldOrEmptyFrames(&last_decoded_state_,
                                             &free_frames_);
@@ -838,13 +833,13 @@ void VCMJitterBuffer::CleanUpOldOrEmptyFrames() {
   }
 }
 
-// Must be called from within |crit_sect_|.
+// Must be called from within |mutex_|.
 bool VCMJitterBuffer::IsPacketRetransmitted(const VCMPacket& packet) const {
   return missing_sequence_numbers_.find(packet.seqNum) !=
          missing_sequence_numbers_.end();
 }
 
-// Must be called under the critical section |crit_sect_|. Should never be
+// Must be called under the critical section |mutex_|. Should never be
 // called with retransmitted frames, they must be filtered out before this
 // function is called.
 void VCMJitterBuffer::UpdateJitterEstimate(const VCMJitterSample& sample,
@@ -856,7 +851,7 @@ void VCMJitterBuffer::UpdateJitterEstimate(const VCMJitterSample& sample,
                        sample.frame_size, incomplete_frame);
 }
 
-// Must be called under the critical section crit_sect_. Should never be
+// Must be called under the critical section mutex_. Should never be
 // called with retransmitted frames, they must be filtered out before this
 // function is called.
 void VCMJitterBuffer::UpdateJitterEstimate(const VCMFrameBuffer& frame,
@@ -870,7 +865,7 @@ void VCMJitterBuffer::UpdateJitterEstimate(const VCMFrameBuffer& frame,
                        frame.size(), incomplete_frame);
 }
 
-// Must be called under the critical section |crit_sect_|. Should never be
+// Must be called under the critical section |mutex_|. Should never be
 // called with retransmitted frames, they must be filtered out before this
 // function is called.
 void VCMJitterBuffer::UpdateJitterEstimate(int64_t latest_packet_time_ms,
diff --git a/modules/video_coding/jitter_buffer.h b/modules/video_coding/jitter_buffer.h
index 2505845d4f..b15ca75ffa 100644
--- a/modules/video_coding/jitter_buffer.h
+++ b/modules/video_coding/jitter_buffer.h
@@ -28,7 +28,7 @@
 #include "modules/video_coding/jitter_buffer_common.h"
 #include "modules/video_coding/jitter_estimator.h"
 #include "rtc_base/constructor_magic.h"
-#include "rtc_base/critical_section.h"
+#include "rtc_base/synchronization/mutex.h"
 #include "rtc_base/thread_annotations.h"
 
 namespace webrtc {
@@ -143,66 +143,66 @@ class VCMJitterBuffer {
   VCMFrameBufferEnum GetFrame(const VCMPacket& packet,
                               VCMFrameBuffer** frame,
                               FrameList** frame_list)
-      RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
+      RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
 
   // Returns true if |frame| is continuous in |decoding_state|, not taking
   // decodable frames into account.
   bool IsContinuousInState(const VCMFrameBuffer& frame,
                            const VCMDecodingState& decoding_state) const
-      RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
+      RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
   // Returns true if |frame| is continuous in the |last_decoded_state_|, taking
   // all decodable frames into account.
   bool IsContinuous(const VCMFrameBuffer& frame) const
-      RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
+      RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
   // Looks for frames in |incomplete_frames_| which are continuous in the
   // provided |decoded_state|. Starts the search from the timestamp of
   // |decoded_state|.
   void FindAndInsertContinuousFramesWithState(
       const VCMDecodingState& decoded_state)
-      RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
+      RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
   // Looks for frames in |incomplete_frames_| which are continuous in
   // |last_decoded_state_| taking all decodable frames into account. Starts
   // the search from |new_frame|.
   void FindAndInsertContinuousFrames(const VCMFrameBuffer& new_frame)
-      RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
-  VCMFrameBuffer* NextFrame() const RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
+      RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
+  VCMFrameBuffer* NextFrame() const RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
   // Returns true if the NACK list was updated to cover sequence numbers up to
   // |sequence_number|. If false a key frame is needed to get into a state where
   // we can continue decoding.
   bool UpdateNackList(uint16_t sequence_number)
-      RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
+      RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
   bool TooLargeNackList() const;
   // Returns true if the NACK list was reduced without problem. If false a key
   // frame is needed to get into a state where we can continue decoding.
-  bool HandleTooLargeNackList() RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
+  bool HandleTooLargeNackList() RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
   bool MissingTooOldPacket(uint16_t latest_sequence_number) const
-      RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
+      RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
   // Returns true if the too old packets was successfully removed from the NACK
   // list. If false, a key frame is needed to get into a state where we can
   // continue decoding.
   bool HandleTooOldPackets(uint16_t latest_sequence_number)
-      RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
+      RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
   // Drops all packets in the NACK list up until |last_decoded_sequence_number|.
   void DropPacketsFromNackList(uint16_t last_decoded_sequence_number);
 
   // Gets an empty frame, creating a new frame if necessary (i.e. increases
   // jitter buffer size).
-  VCMFrameBuffer* GetEmptyFrame() RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
+  VCMFrameBuffer* GetEmptyFrame() RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
 
   // Attempts to increase the size of the jitter buffer. Returns true on
   // success, false otherwise.
-  bool TryToIncreaseJitterBufferSize() RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
+  bool TryToIncreaseJitterBufferSize() RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
 
   // Recycles oldest frames until a key frame is found. Used if jitter buffer is
   // completely full. Returns true if a key frame was found.
-  bool RecycleFramesUntilKeyFrame() RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
+  bool RecycleFramesUntilKeyFrame() RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
 
   // Update rolling average of packets per frame.
   void UpdateAveragePacketsPerFrame(int current_number_packets_);
 
   // Cleans the frame list in the JB from old/empty frames.
   // Should only be called prior to actual use.
-  void CleanUpOldOrEmptyFrames() RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
+  void CleanUpOldOrEmptyFrames() RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
 
   // Returns true if |packet| is likely to have been retransmitted.
   bool IsPacketRetransmitted(const VCMPacket& packet) const;
@@ -217,35 +217,34 @@ class VCMJitterBuffer {
                             unsigned int frame_size,
                             bool incomplete_frame);
 
-  int NonContinuousOrIncompleteDuration()
-      RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
+  int NonContinuousOrIncompleteDuration() RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
 
   uint16_t EstimatedLowSequenceNumber(const VCMFrameBuffer& frame) const;
 
   // Reset frame buffer and return it to free_frames_.
   void RecycleFrameBuffer(VCMFrameBuffer* frame)
-      RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
+      RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
 
   Clock* clock_;
   // If we are running (have started) or not.
   bool running_;
-  rtc::CriticalSection crit_sect_;
+  mutable Mutex mutex_;
   // Event to signal when we have a frame ready for decoder.
   std::unique_ptr<EventWrapper> frame_event_;
   // Number of allocated frames.
   int max_number_of_frames_;
-  UnorderedFrameList free_frames_ RTC_GUARDED_BY(crit_sect_);
-  FrameList decodable_frames_ RTC_GUARDED_BY(crit_sect_);
-  FrameList incomplete_frames_ RTC_GUARDED_BY(crit_sect_);
-  VCMDecodingState last_decoded_state_ RTC_GUARDED_BY(crit_sect_);
+  UnorderedFrameList free_frames_ RTC_GUARDED_BY(mutex_);
+  FrameList decodable_frames_ RTC_GUARDED_BY(mutex_);
+  FrameList incomplete_frames_ RTC_GUARDED_BY(mutex_);
+  VCMDecodingState last_decoded_state_ RTC_GUARDED_BY(mutex_);
   bool first_packet_since_reset_;
 
   // Number of packets in a row that have been too old.
   int num_consecutive_old_packets_;
   // Number of packets received.
-  int num_packets_ RTC_GUARDED_BY(crit_sect_);
+  int num_packets_ RTC_GUARDED_BY(mutex_);
   // Number of duplicated packets received.
-  int num_duplicated_packets_ RTC_GUARDED_BY(crit_sect_);
+  int num_duplicated_packets_ RTC_GUARDED_BY(mutex_);
 
   // Jitter estimation.
   // Filter for estimating jitter.
diff --git a/modules/video_coding/timing.cc b/modules/video_coding/timing.cc
index c62c848c09..f046edf497 100644
--- a/modules/video_coding/timing.cc
+++ b/modules/video_coding/timing.cc
@@ -47,7 +47,7 @@ VCMTiming::~VCMTiming() {
 }
 
 void VCMTiming::Reset() {
-  rtc::CritScope cs(&crit_sect_);
+  MutexLock lock(&mutex_);
   ts_extrapolator_->Reset(clock_->TimeInMilliseconds());
   codec_timer_.reset(new VCMCodecTimer());
   render_delay_ms_ = kDefaultRenderDelayMs;
@@ -58,32 +58,32 @@ void VCMTiming::Reset() {
 }
 
 void VCMTiming::set_render_delay(int render_delay_ms) {
-  rtc::CritScope cs(&crit_sect_);
+  MutexLock lock(&mutex_);
   render_delay_ms_ = render_delay_ms;
 }
 
 void VCMTiming::set_min_playout_delay(int min_playout_delay_ms) {
-  rtc::CritScope cs(&crit_sect_);
+  MutexLock lock(&mutex_);
   min_playout_delay_ms_ = min_playout_delay_ms;
 }
 
 int VCMTiming::min_playout_delay() {
-  rtc::CritScope cs(&crit_sect_);
+  MutexLock lock(&mutex_);
   return min_playout_delay_ms_;
 }
 
 void VCMTiming::set_max_playout_delay(int max_playout_delay_ms) {
-  rtc::CritScope cs(&crit_sect_);
+  MutexLock lock(&mutex_);
   max_playout_delay_ms_ = max_playout_delay_ms;
 }
 
 int VCMTiming::max_playout_delay() {
-  rtc::CritScope cs(&crit_sect_);
+  MutexLock lock(&mutex_);
   return max_playout_delay_ms_;
 }
 
 void VCMTiming::SetJitterDelay(int jitter_delay_ms) {
-  rtc::CritScope cs(&crit_sect_);
+  MutexLock lock(&mutex_);
   if (jitter_delay_ms != jitter_delay_ms_) {
     jitter_delay_ms_ = jitter_delay_ms;
     // When in initial state, set current delay to minimum delay.
@@ -94,7 +94,7 @@ void VCMTiming::SetJitterDelay(int jitter_delay_ms) {
 }
 
 void VCMTiming::UpdateCurrentDelay(uint32_t frame_timestamp) {
-  rtc::CritScope cs(&crit_sect_);
+  MutexLock lock(&mutex_);
   int target_delay_ms = TargetDelayInternal();
 
   if (current_delay_ms_ == 0) {
@@ -135,7 +135,7 @@ void VCMTiming::UpdateCurrentDelay(uint32_t frame_timestamp) {
 
 void VCMTiming::UpdateCurrentDelay(int64_t render_time_ms,
                                    int64_t actual_decode_time_ms) {
-  rtc::CritScope cs(&crit_sect_);
+  MutexLock lock(&mutex_);
   uint32_t target_delay_ms = TargetDelayInternal();
   int64_t delayed_ms =
       actual_decode_time_ms -
@@ -158,20 +158,20 @@ void VCMTiming::StopDecodeTimer(uint32_t /*time_stamp*/,
 }
 
 void VCMTiming::StopDecodeTimer(int32_t decode_time_ms, int64_t now_ms) {
-  rtc::CritScope cs(&crit_sect_);
+  MutexLock lock(&mutex_);
   codec_timer_->AddTiming(decode_time_ms, now_ms);
   assert(decode_time_ms >= 0);
   ++num_decoded_frames_;
 }
 
 void VCMTiming::IncomingTimestamp(uint32_t time_stamp, int64_t now_ms) {
-  rtc::CritScope cs(&crit_sect_);
+  MutexLock lock(&mutex_);
   ts_extrapolator_->Update(now_ms, time_stamp);
 }
 
 int64_t VCMTiming::RenderTimeMs(uint32_t frame_timestamp,
                                 int64_t now_ms) const {
-  rtc::CritScope cs(&crit_sect_);
+  MutexLock lock(&mutex_);
   return RenderTimeMsInternal(frame_timestamp, now_ms);
 }
 
@@ -202,7 +202,7 @@ int VCMTiming::RequiredDecodeTimeMs() const {
 
 int64_t VCMTiming::MaxWaitingTime(int64_t render_time_ms,
                                   int64_t now_ms) const {
-  rtc::CritScope cs(&crit_sect_);
+  MutexLock lock(&mutex_);
 
   const int64_t max_wait_time_ms =
       render_time_ms - now_ms - RequiredDecodeTimeMs() - render_delay_ms_;
@@ -211,7 +211,7 @@ int64_t VCMTiming::MaxWaitingTime(int64_t render_time_ms,
 }
 
 int VCMTiming::TargetVideoDelay() const {
-  rtc::CritScope cs(&crit_sect_);
+  MutexLock lock(&mutex_);
   return TargetDelayInternal();
 }
 
@@ -226,7 +226,7 @@ bool VCMTiming::GetTimings(int* max_decode_ms,
                            int* jitter_buffer_ms,
                            int* min_playout_delay_ms,
                            int* render_delay_ms) const {
-  rtc::CritScope cs(&crit_sect_);
+  MutexLock lock(&mutex_);
   *max_decode_ms = RequiredDecodeTimeMs();
   *current_delay_ms = current_delay_ms_;
   *target_delay_ms = TargetDelayInternal();
@@ -237,12 +237,12 @@ bool VCMTiming::GetTimings(int* max_decode_ms,
 }
 
 void VCMTiming::SetTimingFrameInfo(const TimingFrameInfo& info) {
-  rtc::CritScope cs(&crit_sect_);
+  MutexLock lock(&mutex_);
   timing_frame_info_.emplace(info);
 }
 
 absl::optional<TimingFrameInfo> VCMTiming::GetTimingFrameInfo() {
-  rtc::CritScope cs(&crit_sect_);
+  MutexLock lock(&mutex_);
   return timing_frame_info_;
 }
 
diff --git a/modules/video_coding/timing.h b/modules/video_coding/timing.h
index c9efcb13b0..75b8e7d99d 100644
--- a/modules/video_coding/timing.h
+++ b/modules/video_coding/timing.h
@@ -16,7 +16,7 @@
 #include "absl/types/optional.h"
 #include "api/video/video_timing.h"
 #include "modules/video_coding/codec_timer.h"
-#include "rtc_base/critical_section.h"
+#include "rtc_base/synchronization/mutex.h"
 #include "rtc_base/thread_annotations.h"
 
 namespace webrtc {
@@ -104,30 +104,30 @@ class VCMTiming {
   enum { kDelayMaxChangeMsPerS = 100 };
 
  protected:
-  int RequiredDecodeTimeMs() const RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
+  int RequiredDecodeTimeMs() const RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
   int64_t RenderTimeMsInternal(uint32_t frame_timestamp, int64_t now_ms) const
-      RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
-  int TargetDelayInternal() const RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
+      RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
+  int TargetDelayInternal() const RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
 
  private:
-  rtc::CriticalSection crit_sect_;
+  mutable Mutex mutex_;
   Clock* const clock_;
-  bool master_ RTC_GUARDED_BY(crit_sect_);
-  TimestampExtrapolator* ts_extrapolator_ RTC_GUARDED_BY(crit_sect_);
-  std::unique_ptr<VCMCodecTimer> codec_timer_ RTC_GUARDED_BY(crit_sect_);
-  int render_delay_ms_ RTC_GUARDED_BY(crit_sect_);
+  bool master_ RTC_GUARDED_BY(mutex_);
+  TimestampExtrapolator* ts_extrapolator_ RTC_GUARDED_BY(mutex_);
+  std::unique_ptr<VCMCodecTimer> codec_timer_ RTC_GUARDED_BY(mutex_);
+  int render_delay_ms_ RTC_GUARDED_BY(mutex_);
   // Best-effort playout delay range for frames from capture to render.
   // The receiver tries to keep the delay between |min_playout_delay_ms_|
   // and |max_playout_delay_ms_| taking the network jitter into account.
   // A special case is where min_playout_delay_ms_ = max_playout_delay_ms_ = 0,
   // in which case the receiver tries to play the frames as they arrive.
-  int min_playout_delay_ms_ RTC_GUARDED_BY(crit_sect_);
-  int max_playout_delay_ms_ RTC_GUARDED_BY(crit_sect_);
-  int jitter_delay_ms_ RTC_GUARDED_BY(crit_sect_);
-  int current_delay_ms_ RTC_GUARDED_BY(crit_sect_);
-  uint32_t prev_frame_timestamp_ RTC_GUARDED_BY(crit_sect_);
-  absl::optional<TimingFrameInfo> timing_frame_info_ RTC_GUARDED_BY(crit_sect_);
-  size_t num_decoded_frames_ RTC_GUARDED_BY(crit_sect_);
+  int min_playout_delay_ms_ RTC_GUARDED_BY(mutex_);
+  int max_playout_delay_ms_ RTC_GUARDED_BY(mutex_);
+  int jitter_delay_ms_ RTC_GUARDED_BY(mutex_);
+  int current_delay_ms_ RTC_GUARDED_BY(mutex_);
+  uint32_t prev_frame_timestamp_ RTC_GUARDED_BY(mutex_);
+  absl::optional<TimingFrameInfo> timing_frame_info_ RTC_GUARDED_BY(mutex_);
+  size_t num_decoded_frames_ RTC_GUARDED_BY(mutex_);
 };
 }  // namespace webrtc
 
diff --git a/modules/video_coding/video_coding_impl.h b/modules/video_coding/video_coding_impl.h
index eaab639dbf..440d1998bc 100644
--- a/modules/video_coding/video_coding_impl.h
+++ b/modules/video_coding/video_coding_impl.h
@@ -24,6 +24,7 @@
 #include "modules/video_coding/receiver.h"
 #include "modules/video_coding/timing.h"
 #include "rtc_base/one_time_event.h"
+#include "rtc_base/synchronization/mutex.h"
 #include "rtc_base/synchronization/sequence_checker.h"
 #include "rtc_base/thread_annotations.h"
 #include "rtc_base/thread_checker.h"
@@ -100,7 +101,7 @@ class VideoReceiver : public Module {
   rtc::ThreadChecker decoder_thread_checker_;
   rtc::ThreadChecker module_thread_checker_;
   Clock* const clock_;
-  rtc::CriticalSection process_crit_;
+  Mutex process_mutex_;
   VCMTiming* _timing;
   VCMReceiver _receiver;
   VCMDecodedFrameCallback _decodedFrameCallback;
@@ -111,8 +112,8 @@ class VideoReceiver : public Module {
   VCMPacketRequestCallback* _packetRequestCallback;
 
   // Used on both the module and decoder thread.
-  bool _scheduleKeyRequest RTC_GUARDED_BY(process_crit_);
-  bool drop_frames_until_keyframe_ RTC_GUARDED_BY(process_crit_);
+  bool _scheduleKeyRequest RTC_GUARDED_BY(process_mutex_);
+  bool drop_frames_until_keyframe_ RTC_GUARDED_BY(process_mutex_);
 
   // Modified on the construction thread while not attached to the process
   // thread.  Once attached to the process thread, its value is only read
diff --git a/modules/video_coding/video_receiver.cc b/modules/video_coding/video_receiver.cc
index a817293f2f..a227a8c337 100644
--- a/modules/video_coding/video_receiver.cc
+++ b/modules/video_coding/video_receiver.cc
@@ -31,7 +31,6 @@
 #include "modules/video_coding/timing.h"
 #include "modules/video_coding/video_coding_impl.h"
 #include "rtc_base/checks.h"
-#include "rtc_base/critical_section.h"
 #include "rtc_base/location.h"
 #include "rtc_base/logging.h"
 #include "rtc_base/one_time_event.h"
@@ -71,7 +70,7 @@ void VideoReceiver::Process() {
     _keyRequestTimer.Processed();
     bool request_key_frame = _frameTypeCallback != nullptr;
     if (request_key_frame) {
-      rtc::CritScope cs(&process_crit_);
+      MutexLock lock(&process_mutex_);
       request_key_frame = _scheduleKeyRequest;
     }
     if (request_key_frame)
@@ -94,7 +93,7 @@ void VideoReceiver::Process() {
         ret = RequestKeyFrame();
       }
       if (ret == VCM_OK && !nackList.empty()) {
-        rtc::CritScope cs(&process_crit_);
+        MutexLock lock(&process_mutex_);
         if (_packetRequestCallback != nullptr) {
           _packetRequestCallback->ResendPackets(&nackList[0], nackList.size());
         }
@@ -183,7 +182,7 @@ int32_t VideoReceiver::Decode(uint16_t maxWaitTimeMs) {
 
   bool drop_frame = false;
   {
-    rtc::CritScope cs(&process_crit_);
+    MutexLock lock(&process_mutex_);
     if (drop_frames_until_keyframe_) {
       // Still getting delta frames, schedule another keyframe request as if
       // decode failed.
@@ -229,7 +228,7 @@ int32_t VideoReceiver::RequestKeyFrame() {
     if (ret < 0) {
       return ret;
     }
-    rtc::CritScope cs(&process_crit_);
+    MutexLock lock(&process_mutex_);
     _scheduleKeyRequest = false;
   } else {
     return VCM_MISSING_CALLBACK;
@@ -291,7 +290,7 @@ int32_t VideoReceiver::IncomingPacket(const uint8_t* incomingPayload,
   // request scheduling to throttle the requests.
   if (ret == VCM_FLUSH_INDICATOR) {
     {
-      rtc::CritScope cs(&process_crit_);
+      MutexLock lock(&process_mutex_);
       drop_frames_until_keyframe_ = true;
     }
     RequestKeyFrame();