Replace the guts of AudioRendererBase with calls to scaling algorithm.

media/filters/audio_renderer_base.h

 // Copyright (c) 2009 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.
 
 // AudioRendererBase takes care of the tricky queuing work and provides simple
 // methods for subclasses to peek and poke at audio data.  In addition to
 // AudioRenderer interface methods this classes doesn't implement, subclasses
 // must also implement the following methods:
 //   OnInitialized
 //   OnStop
 //
 // The general assumption is that subclasses start a callback-based audio thread
 // which needs to be filled with decoded audio data.  AudioDecoderBase provides
 // FillBuffer which handles filling the provided buffer, dequeuing items,
 // scheduling additional reads and updating the clock.  In a sense,
 // AudioRendererBase is the producer and the subclass is the consumer.
 
 #ifndef MEDIA_FILTERS_AUDIO_RENDERER_BASE_H_
 #define MEDIA_FILTERS_AUDIO_RENDERER_BASE_H_
 
 #include <deque>
 
 #include "base/lock.h"
 #include "media/base/buffers.h"
 #include "media/base/factory.h"
 #include "media/base/filters.h"
+#include "media/filters/audio_renderer_algorithm_base.h"
 
 namespace media {
 
 class AudioRendererBase : public AudioRenderer {
  public:
   // MediaFilter implementation.
   virtual void Play(FilterCallback* callback);
   virtual void Pause(FilterCallback* callback);
   virtual void Stop();
 
   virtual void Seek(base::TimeDelta time, FilterCallback* callback);
 
   // AudioRenderer implementation.
   virtual void Initialize(AudioDecoder* decoder, FilterCallback* callback);
 
  protected:
-  // The default maximum size of the queue.
-  static const size_t kDefaultMaxQueueSize;
-
   // Only allow a factory to create this class.
-  explicit AudioRendererBase(size_t max_queue_size);
+  AudioRendererBase();
   virtual ~AudioRendererBase();
 
   // Called by Initialize().  |media_format| is the format of the AudioDecoder.
   // Subclasses should return true if they were able to initialize, false
   // otherwise.
   virtual bool OnInitialize(const MediaFormat& media_format) = 0;
 
   // Called by Stop().  Subclasses should perform any necessary cleanup during
   // this time, such as stopping any running threads.
   virtual void OnStop() = 0;
 
   // Called when a AudioDecoder::Read() completes and decrements
   // |pending_reads_|.
   virtual void OnReadComplete(Buffer* buffer_in);
 
-  // Fills the given buffer with audio data by dequeuing buffers and copying the
-  // data into the |dest|.  FillBuffer() also takes care of updating the clock.
-  // Returns the number of bytes copied into |dest|, which may be less than
-  // equal to |len|.
+  // Fills the given buffer with audio data by delegating to its |algorithm_|.
+  // FillBuffer() also takes care of updating the clock. Returns the number of
+  // bytes copied into |dest|, which may be less than or equal to |len|.
   //
   // If this method is returns less bytes than |len| (including zero), it could
   // be a sign that the pipeline is stalled or unable to stream the data fast
   // enough.  In such scenarios, the callee should zero out unused portions
   // of their buffer to playback silence.
   //
   // FillBuffer() updates the pipeline's playback timestamp. If FillBuffer() is
   // not called at the same rate as audio samples are played, then the reported
   // timestamp in the pipeline will be ahead of the actual audio playback. In
   // this case |playback_delay| should be used to indicate when in the future
   // should the filled buffer be played. If FillBuffer() is called as the audio
   // hardware plays the buffer, then |playback_delay| should be zero.
   //
   // Safe to call on any thread.
   size_t FillBuffer(uint8* dest,
                     size_t len,
-                    float rate,
                     const base::TimeDelta& playback_delay);
 
   // Helper to parse a media format and return whether we were successful
   // retrieving all the information we care about.
   static bool ParseMediaFormat(const MediaFormat& media_format,
                                int* channels_out, int* sample_rate_out,
                                int* sample_bits_out);
 
+  // Get/Set the playback rate of |algorithm_|.
+  virtual void SetPlaybackRate(float playback_rate);
+  virtual float GetPlaybackRate();
+
  private:
   // Helper method that schedules an asynchronous read from the decoder and
   // increments |pending_reads_|.
   //
   // Safe to call from any thread.
   void ScheduleRead_Locked();
 
   // Audio decoder.
   scoped_refptr<AudioDecoder> decoder_;
 
-  // Maximum queue size, configuration parameter passed in during construction.
-  size_t max_queue_size_;
+  // Algorithm for scaling audio.
+  scoped_ptr<AudioRendererAlgorithmBase> algorithm_;
 
-  // Queued audio data.
-  typedef std::deque< scoped_refptr<Buffer> > BufferQueue;
-  BufferQueue queue_;
   Lock lock_;
 
-  // Remembers the amount of remaining audio data for the front buffer.
-  size_t data_offset_;
-
   // Simple state tracking variable.
   enum State {
     kUninitialized,
     kPaused,
     kSeeking,
     kPlaying,
     kStopped,
     kError,
   };
   State state_;
@@ skipping 12 matching lines @@
   // Filter callbacks.
   scoped_ptr<FilterCallback> pause_callback_;
   scoped_ptr<FilterCallback> seek_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioRendererBase);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_AUDIO_RENDERER_BASE_H_