Cleanup OPUS decoder. Remove extraneous transforms and copies.

media/filters/opus_audio_decoder.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_OPUS_AUDIO_DECODER_H_
 #define MEDIA_FILTERS_OPUS_AUDIO_DECODER_H_
 
 #include "base/callback.h"
 #include "base/memory/weak_ptr.h"
 #include "base/time/time.h"
 #include "media/base/audio_decoder.h"
 #include "media/base/demuxer_stream.h"
+#include "media/base/sample_format.h"
 
 struct OpusMSDecoder;
 
 namespace base {
 class MessageLoopProxy;
 }
 
 namespace media {
 
 class AudioBuffer;
@@ skipping 32 matching lines @@
 
   scoped_refptr<base::MessageLoopProxy> message_loop_;
   base::WeakPtrFactory<OpusAudioDecoder> weak_factory_;
   base::WeakPtr<OpusAudioDecoder> weak_this_;
 
   DemuxerStream* demuxer_stream_;
   StatisticsCB statistics_cb_;
   OpusMSDecoder* opus_decoder_;
 
   // Decoded audio format.
-  int bits_per_channel_;
   ChannelLayout channel_layout_;
   int samples_per_second_;
+  const SampleFormat sample_format_;
+  const int bits_per_channel_;
 
   // Used for computing output timestamps.
   scoped_ptr<AudioTimestampHelper> output_timestamp_helper_;
   base::TimeDelta last_input_timestamp_;
 
   ReadCB read_cb_;
 
   // Number of frames to be discarded from the start of the packet. This value
   // is respected for all packets except for the first one in the stream. For
   // the first packet in the stream, |frame_delay_at_start_| is used. This is
   // usually set to the SeekPreRoll value from the container whenever a seek
   // happens.
   int frames_to_discard_;
 
   // Number of frames to be discarded at the start of the stream. This value
-  // is typically the CodecDelay value from the container.
+  // is typically the CodecDelay value from the container.  This value should
+  // only be applied when input timestamp is |start_input_timestamp_|.
   int frame_delay_at_start_;
+  base::TimeDelta start_input_timestamp_;
 
   // Timestamp to be subtracted from all the frames. This is typically computed
   // from the CodecDelay value in the container.
   base::TimeDelta timestamp_offset_;
 
-  // Buffer for output from libopus.
-  scoped_ptr<int16[]> output_buffer_;
-
   DISALLOW_IMPLICIT_CONSTRUCTORS(OpusAudioDecoder);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_OPUS_AUDIO_DECODER_H_