1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef MEDIA_BASE_AUDIO_RENDERER_H_ 6 #define MEDIA_BASE_AUDIO_RENDERER_H_ 7 8 #include "base/callback.h" 9 #include "base/time/time.h" 10 #include "media/base/buffering_state.h" 11 #include "media/base/media_export.h" 12 #include "media/base/pipeline_status.h" 13 14 namespace media { 15 16 class DemuxerStream; 17 class TimeSource; 18 19 class MEDIA_EXPORT AudioRenderer { 20 public: 21 AudioRenderer(); 22 23 // Stop all operations and fire all pending callbacks. 24 virtual ~AudioRenderer(); 25 26 // Initialize an AudioRenderer with |stream|, executing |init_cb| upon 27 // completion. 28 // 29 // |statistics_cb| is executed periodically with audio rendering stats. 30 // 31 // |buffering_state_cb| is executed when audio rendering has either run out of 32 // data or has enough data to continue playback. 33 // 34 // |ended_cb| is executed when audio rendering has reached the end of stream. 35 // 36 // |error_cb| is executed if an error was encountered. 37 virtual void Initialize(DemuxerStream* stream, 38 const PipelineStatusCB& init_cb, 39 const StatisticsCB& statistics_cb, 40 const BufferingStateCB& buffering_state_cb, 41 const base::Closure& ended_cb, 42 const PipelineStatusCB& error_cb) = 0; 43 44 // Returns the TimeSource associated with audio rendering. 45 virtual TimeSource* GetTimeSource() = 0; 46 47 // Discard any audio data, executing |callback| when completed. 48 // 49 // Clients should expect |buffering_state_cb| to be called with 50 // BUFFERING_HAVE_NOTHING while flushing is in progress. 51 virtual void Flush(const base::Closure& callback) = 0; 52 53 // Starts playback by reading from |stream| and decoding and rendering audio. 54 // 55 // Only valid to call after a successful Initialize() or Flush(). 56 virtual void StartPlaying() = 0; 57 58 // Sets the output volume. 59 virtual void SetVolume(float volume) = 0; 60 61 private: 62 DISALLOW_COPY_AND_ASSIGN(AudioRenderer); 63 }; 64 65 } // namespace media 66 67 #endif // MEDIA_BASE_AUDIO_RENDERER_H_ 68