Merge from Chromium at DEPS revision r167172

This commit was generated by merge_to_master.py.

Change-Id: Ib8d56fd5ae39a2d7e8c91dcd76cc6d13f25f2aab

1 files changed, 85 insertions, 0 deletions

diff --git a/media/base/buffers.h b/media/base/buffers.h
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+++ b/media/base/buffers.h
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+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Defines a base class for representing timestamped media data. Every buffer
+// contains a timestamp in microseconds describing the relative position of
+// the buffer within the media stream, and the duration in microseconds for
+// the length of time the buffer will be rendered.
+//
+// Timestamps are derived directly from the encoded media file and are commonly
+// known as the presentation timestamp (PTS).  Durations are a best-guess and
+// are usually derived from the sample/frame rate of the media file.
+//
+// Due to encoding and transmission errors, it is not guaranteed that timestamps
+// arrive in a monotonically increasing order nor that the next timestamp will
+// be equal to the previous timestamp plus the duration.
+//
+// In the ideal scenario for a 25fps movie, buffers are timestamped as followed:
+//
+//               Buffer0      Buffer1      Buffer2      ...      BufferN
+// Timestamp:        0us      40000us      80000us      ...   (N*40000)us
+// Duration*:    40000us      40000us      40000us      ...       40000us
+//
+//  *25fps = 0.04s per frame = 40000us per frame
+
+#ifndef MEDIA_BASE_BUFFERS_H_
+#define MEDIA_BASE_BUFFERS_H_
+
+#include "base/basictypes.h"
+#include "base/memory/ref_counted.h"
+#include "base/time.h"
+#include "media/base/media_export.h"
+
+namespace media {
+
+// Indicates an invalid or missing timestamp.
+MEDIA_EXPORT extern inline base::TimeDelta kNoTimestamp() {
+  return base::TimeDelta::FromMicroseconds(kint64min);
+}
+
+// Represents an infinite stream duration.
+MEDIA_EXPORT extern inline base::TimeDelta kInfiniteDuration() {
+  return base::TimeDelta::FromMicroseconds(kint64max);
+}
+
+class MEDIA_EXPORT Buffer : public base::RefCountedThreadSafe<Buffer> {
+ public:
+  // Returns a read only pointer to the buffer data.
+  virtual const uint8* GetData() const = 0;
+
+  // Returns the size of valid data in bytes.
+  virtual int GetDataSize() const = 0;
+
+  // If there's no data in this buffer, it represents end of stream.
+  bool IsEndOfStream() const;
+
+  base::TimeDelta GetTimestamp() const {
+    return timestamp_;
+  }
+  void SetTimestamp(const base::TimeDelta& timestamp) {
+    timestamp_ = timestamp;
+  }
+
+  base::TimeDelta GetDuration() const {
+    return duration_;
+  }
+  void SetDuration(const base::TimeDelta& duration) {
+    duration_ = duration;
+  }
+
+ protected:
+  friend class base::RefCountedThreadSafe<Buffer>;
+  Buffer(base::TimeDelta timestamp, base::TimeDelta duration);
+  virtual ~Buffer();
+
+ private:
+  base::TimeDelta timestamp_;
+  base::TimeDelta duration_;
+
+  DISALLOW_COPY_AND_ASSIGN(Buffer);
+};
+
+}  // namespace media
+
+#endif  // MEDIA_BASE_BUFFERS_H_