Improving WebM video duration estimation.

media/filters/source_buffer_range.h

 // Copyright 2014 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_RANGE_H_
 #define MEDIA_FILTERS_SOURCE_BUFFER_RANGE_H_
 
 #include <map>
 
 #include "base/callback.h"
@@ skipping 188 matching lines @@
   // Adds all buffers which overlap [start, end) to the end of |buffers|.  If
   // no buffers exist in the range returns false, true otherwise.
   bool GetBuffersInRange(DecodeTimestamp start, DecodeTimestamp end,
                          BufferQueue* buffers);
 
   int size_in_bytes() const { return size_in_bytes_; }
 
  private:
   typedef std::map<DecodeTimestamp, int> KeyframeMap;
 
+  // Called during AppendBuffersToEnd to adjust estimated duration at the
+  // end of the last append to match the delta in timestamps between
+  // the last append and the upcoming append. This is a workaround for
+  // WebM media where a duration is not always specified.
+  void AdjustEstimatedDurationForNewAppend(const BufferQueue& new_buffers);
+
   // Seeks the range to the next keyframe after |timestamp|. If
   // |skip_given_timestamp| is true, the seek will go to a keyframe with a
   // timestamp strictly greater than |timestamp|.
   void SeekAhead(DecodeTimestamp timestamp, bool skip_given_timestamp);
 
   // Returns an iterator in |buffers_| pointing to the buffer at |timestamp|.
   // If |skip_given_timestamp| is true, this returns the first buffer with
   // timestamp greater than |timestamp|.
   BufferQueue::iterator GetBufferItrAt(
       DecodeTimestamp timestamp, bool skip_given_timestamp);
 
   // Returns an iterator in |keyframe_map_| pointing to the next keyframe after
   // |timestamp|. If |skip_given_timestamp| is true, this returns the first
   // keyframe with a timestamp strictly greater than |timestamp|.
   KeyframeMap::iterator GetFirstKeyframeAt(
       DecodeTimestamp timestamp, bool skip_given_timestamp);
 
   // Returns an iterator in |keyframe_map_| pointing to the first keyframe
   // before or at |timestamp|.
-  KeyframeMap::iterator GetFirstKeyframeBefore(DecodeTimestamp timestamp);
+  KeyframeMap::iterator GetFirstKeyframeAtOrBefore(DecodeTimestamp timestamp);
 
   // Helper method to delete buffers in |buffers_| starting at
   // |starting_point|, an iterator in |buffers_|.
   // Returns true if everything in the range was removed. Returns
   // false if the range still contains buffers.
   bool TruncateAt(const BufferQueue::iterator& starting_point,
                   BufferQueue* deleted_buffers);
 
   // Frees the buffers in |buffers_| from [|start_point|,|ending_point|) and
   // updates the |size_in_bytes_| accordingly. Does not update |keyframe_map_|.
@@ skipping 40 matching lines @@
 
   // Stores the amount of memory taken up by the data in |buffers_|.
   int size_in_bytes_;
 
   DISALLOW_COPY_AND_ASSIGN(SourceBufferRange);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_SOURCE_BUFFER_RANGE_H_