Add initial implementation of SourceBufferStream

media/base/buffers.h

 // 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/logging.h"
 #include "base/memory/ref_counted.h"
 #include "base/time.h"
 #include "media/base/media_export.h"
 
 namespace media {
 
 class DecryptConfig;
 
 // Indicates an invalid or missing timestamp.
 MEDIA_EXPORT extern inline base::TimeDelta kNoTimestamp() {
@@ skipping 26 matching lines @@
     timestamp_ = timestamp;
   }
 
   base::TimeDelta GetDuration() const {
     return duration_;
   }
   void SetDuration(const base::TimeDelta& duration) {
     duration_ = duration;
   }
 
+  virtual bool IsKeyframe() const {

[scherkus (not reviewing), 2012/04/25 22:59:00]

don't inline virtual methods in .h
http://dev.chromium.org/developers/coding-style/cpp-dos-and-donts

also couldn't virtual + MockDataBuffer be replaced with a call to SetKeyframe()
in the unit test?

[vrk (LEFT CHROMIUM), 2012/04/25 23:25:48]

Yeahhh as I explained offline, I was worried that people would use these methods
when they're not actually supported yet, but probably not worth worrying about.
Devirtualized and got rid of the Mock.

We could/should? have ChunkedDemuxer use a special derived class of Buffer that
has these methods on it, so as not to pollute the Buffer base class with methods
that only ChunkDemuxer + friends care about. But since we're not sure yet if
that's the right direction to go in, I'll just keep the methods in Buffer with a
TODO.

+    // TODO(vrk): Remove this when keyframes are marked as such.
+    NOTIMPLEMENTED();
+
+    return is_keyframe_;
+  }
+
+  void SetKeyframe(bool is_keyframe) {
+    is_keyframe_ = is_keyframe;
+  }
+
  protected:
   friend class base::RefCountedThreadSafe<Buffer>;
   Buffer(base::TimeDelta timestamp, base::TimeDelta duration);
   virtual ~Buffer();
 
  private:
   base::TimeDelta timestamp_;
   base::TimeDelta duration_;
+  bool is_keyframe_;
 
   DISALLOW_COPY_AND_ASSIGN(Buffer);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_BUFFERS_H_