Remove buffer duration calculation from WebMClusterParser and update SourceBufferStream accordingly

media/filters/source_buffer_stream.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.
 
 #ifndef MEDIA_FILTERS_SOURCE_BUFFER_STREAM_H_
 #define MEDIA_FILTERS_SOURCE_BUFFER_STREAM_H_
 
 #include <deque>
 #include <list>
 #include <utility>
@@ skipping 10 matching lines @@
 class SourceBufferRange;
 
 // SourceBufferStream is a data structure that stores media Buffers in ranges.
 // Buffers can be appended out of presentation order. Buffers are retrieved by
 // seeking to the desired start point and calling GetNextBuffer(). Buffers are
 // returned in sequential presentation order.
 class MEDIA_EXPORT SourceBufferStream {
  public:
   typedef std::deque<scoped_refptr<StreamParserBuffer> > BufferQueue;
 
-  SourceBufferStream();
   explicit SourceBufferStream(const AudioDecoderConfig& audio_config);
   explicit SourceBufferStream(const VideoDecoderConfig& video_config);
 
   ~SourceBufferStream();
 
+  // Signals that the next buffers appended are part of a new media segment
+  // starting at |media_segment_start_time|.
+  void OnNewMediaSegment(base::TimeDelta media_segment_start_time);
+
   // Add the |buffers| to the SourceBufferStream. Buffers within the queue are
   // expected to be in order, but multiple calls to Append() may add buffers out
   // of order or overlapping. Assumes all buffers within |buffers| are in
   // presentation order and are non-overlapping.
-  // |media_segment_start_time| refers to the starting timestamp for the media
-  // segment to which these buffers belong.
   // Returns true if Append() was successful, false if |buffers| are not added.
   // TODO(vrk): Implement garbage collection. (crbug.com/125070)
-  bool Append(const BufferQueue& buffers,
-              base::TimeDelta media_segment_start_time);
+  bool Append(const BufferQueue& buffers);
 
   // Changes the SourceBufferStream's state so that it will start returning
   // buffers starting from the closest keyframe before |timestamp|.
   void Seek(base::TimeDelta timestamp);
 
   // Returns true if the SourceBufferStream has seeked to a time without
   // buffered data and is waiting for more data to be appended.
   bool IsSeekPending() const;
 
   // Fills |out_buffer| with a new buffer. Buffers are presented in order from
@@ skipping 18 matching lines @@
   // (if there are no gaps between the current position and the remaining data).
   bool CanEndOfStream() const;
 
   const AudioDecoderConfig& GetCurrentAudioDecoderConfig() {
     return audio_config_;
   }
   const VideoDecoderConfig& GetCurrentVideoDecoderConfig() {
     return video_config_;
   }
 
+  base::TimeDelta max_interbuffer_distance() const {
+    return max_interbuffer_distance_;
+  }
+
  private:
   typedef std::list<SourceBufferRange*> RangeList;
 
   // Appends |new_buffers| into |range_for_new_buffers_itr|, handling start and
   // end overlaps if necessary.
   void InsertIntoExistingRange(

[acolwell GONE FROM CHROMIUM, 2012/07/09 18:15:55]

nit: Document out parameters here too.

[vrk (LEFT CHROMIUM), 2012/07/10 00:05:33]

Done.

       const RangeList::iterator& range_for_new_buffers_itr,
-      const BufferQueue& new_buffers);
+      const BufferQueue& new_buffers,
+      bool* deleted_next_buffer, BufferQueue* deleted_buffers);
 
   // Resolve overlapping ranges such that no ranges overlap anymore.
   // |range_with_new_buffers_itr| points to the range that has newly appended
   // buffers.
+  // |deleted_next_buffer| is an output parameter that is true if the next
+  // buffer that would have been returned from GetNextBuffer() was deleted
+  // during this call.
+  // |deleted_buffers| is an output parameter containing candidates for
+  // |track_buffer_|.
   void ResolveCompleteOverlaps(
-      const RangeList::iterator& range_with_new_buffers_itr);
-  void ResolveEndOverlap(const RangeList::iterator& range_with_new_buffers_itr);
+      const RangeList::iterator& range_with_new_buffers_itr,
+      bool* deleted_next_buffer, BufferQueue* deleted_buffers);
+  void ResolveEndOverlap(
+      const RangeList::iterator& range_with_new_buffers_itr,
+      bool* deleted_next_buffer, BufferQueue* deleted_buffers);
 
   // This method is a bit tricky to describe. When what would have been the
   // next buffer returned from |selected_range_| is overlapped by new data,
   // the |selected_range_| seeks forward to the next keyframe after (or at) the
   // next buffer timestamp and the overlapped buffers are deleted. But for
   // smooth playback between the old data to the new data's keyframe, some of
   // these |deleted_buffers| may be temporarily saved into |track_buffer_|.
   // UpdateTrackBuffer() takes these |deleted_buffers| and decides whether it
   // wants to save any buffers into |track_buffer_|.
   // TODO(vrk): This is a little crazy! Ideas for cleanup in crbug.com/129623.
   void UpdateTrackBuffer(const BufferQueue& deleted_buffers);
 
   // Checks to see if |range_with_new_buffers_itr| can be merged with the range
   // next to it, and merges them if so.
   void MergeWithAdjacentRangeIfNecessary(
       const RangeList::iterator& range_with_new_buffers_itr);
 
   // Helper method that returns the timestamp for the next buffer that
   // |selected_range_| will return from GetNextBuffer() call, or kNoTimestamp()
   // if in between seeking (i.e. |selected_range_| is null).
   base::TimeDelta GetNextBufferTimestamp();
 
-  // Finds the range into which |new_buffers| should be inserted and returns the
-  // iterator pointing to it. Returns |ranges_.end()| if no existing range
-  // should contain |new_buffers|.
-  RangeList::iterator FindExistingRangeFor(const BufferQueue& new_buffers);
+  // Returns the timestamp of the last buffer in the |selected_range_| or
+  // kNoTimestamp() if |selected_range_| is null.
+  base::TimeDelta GetEndBufferTimestamp();

[acolwell GONE FROM CHROMIUM, 2012/07/09 18:15:55]

nit: s/End/Last/ ?

[vrk (LEFT CHROMIUM), 2012/07/10 00:05:33]

Going to keep "End" timestamp even though it's a little clunky because
GetLastBufferTimestamp() can sound like it means "previous" buffer, especially
since we have a GetNextBufferTimestamp() method.

+
+  // Finds the range that should contain a media segment that begins with
+  // |start_timestamp| and returns the iterator pointing to it. Returns
+  // |ranges_.end()| if there's no such existing range.
+  RangeList::iterator FindExistingRangeFor(base::TimeDelta start_timestamp);
 
   // Inserts |new_range| into |ranges_| preserving sorted order. Returns an
   // iterator in |ranges_| that points to |new_range|.
   RangeList::iterator AddToRanges(SourceBufferRange* new_range);
 
   // Returns an iterator that points to the place in |ranges_| where
   // |selected_range_| lives.
   RangeList::iterator GetSelectedRangeItr();
 
+  // Returns true if the timestamps of |buffers| are monotonically increasing
+  // since the previous append to the media segment, false otherwise.
+  bool IsMonotonicallyIncreasing(const BufferQueue& buffers);
+
+  // Measures the distances between buffer timestamps and tracks the max.
+  void UpdateMaxInterbufferDistance(const BufferQueue& buffers);
+
   // List of disjoint buffered ranges, ordered by start time.
   RangeList ranges_;
 
   AudioDecoderConfig audio_config_;
   VideoDecoderConfig video_config_;
 
   // True if more data needs to be appended before the Seek() can complete,
   // false if no Seek() has been requested or the Seek() is completed.
   bool seek_pending_;
 
   // Timestamp of the last request to Seek().
   base::TimeDelta seek_buffer_timestamp_;
 
   // Pointer to the seeked-to Range. This is the range from which
   // GetNextBuffer() calls are fulfilled after the |track_buffer_| has been
   // emptied.
   SourceBufferRange* selected_range_;
 
   // Queue of the next buffers to be returned from calls to GetNextBuffer(). If
   // |track_buffer_| is empty, return buffers from |selected_range_|.
   BufferQueue track_buffer_;
 
   // True when EndOfStream() has been called and GetNextBuffer() should return
   // EOS buffers for read requests beyond the buffered data.  False initially.
   bool end_of_stream_;
 
+  // The start time of the current media segment being appended.
+  base::TimeDelta media_segment_start_time_;
+
+  // Points to the range containing the current media segment being appended.
+  RangeList::iterator range_for_next_append_;
+
+  // True when the next call to Append() begins a new media segment.
+  bool new_media_segment_;
+
+  // The timestamp of the last buffer appended to the media segment, set to
+  // kNoTimestamp() if the beginning of the segment.
+  base::TimeDelta last_buffer_timestamp_;
+
+  // Stores the largest distance between two adjacent buffers in this stream.
+  base::TimeDelta max_interbuffer_distance_;
+
   DISALLOW_COPY_AND_ASSIGN(SourceBufferStream);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_SOURCE_BUFFER_STREAM_H_