| // 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_BASE_AUDIO_RENDERER_H_ |
| #define MEDIA_BASE_AUDIO_RENDERER_H_ |
| |
| #include "base/callback.h" |
| #include "base/memory/ref_counted.h" |
| #include "base/time/time.h" |
| #include "media/base/media_export.h" |
| #include "media/base/pipeline_status.h" |
| |
| namespace media { |
| |
| class DemuxerStream; |
| |
| class MEDIA_EXPORT AudioRenderer { |
| public: |
| // First parameter is the current time that has been rendered. |
| // Second parameter is the maximum time value that the clock cannot exceed. |
| typedef base::Callback<void(base::TimeDelta, base::TimeDelta)> TimeCB; |
| |
| AudioRenderer(); |
| virtual ~AudioRenderer(); |
| |
| // Initialize an AudioRenderer with |stream|, executing |init_cb| upon |
| // completion. |
| // |
| // |statistics_cb| is executed periodically with audio rendering stats. |
| // |
| // |underflow_cb| is executed when the renderer runs out of data to pass to |
| // the audio card during playback. ResumeAfterUnderflow() must be called |
| // to resume playback. Pause(), Preroll(), or Stop() cancels the underflow |
| // condition. |
| // |
| // |time_cb| is executed whenever time has advanced by way of audio rendering. |
| // |
| // |ended_cb| is executed when audio rendering has reached the end of stream. |
| // |
| // |error_cb| is executed if an error was encountered. |
| virtual void Initialize(DemuxerStream* stream, |
| const PipelineStatusCB& init_cb, |
| const StatisticsCB& statistics_cb, |
| const base::Closure& underflow_cb, |
| const TimeCB& time_cb, |
| const base::Closure& ended_cb, |
| const PipelineStatusCB& error_cb) = 0; |
| |
| // Signal audio playback to start at the current rate. It is expected that |
| // |time_cb| will eventually start being run with time updates. |
| virtual void StartRendering() = 0; |
| |
| // Signal audio playback to stop until further notice. It is expected that |
| // |time_cb| will no longer be run. |
| virtual void StopRendering() = 0; |
| |
| // Discard any audio data, executing |callback| when completed. |
| virtual void Flush(const base::Closure& callback) = 0; |
| |
| // Start prerolling audio data for samples starting at |time|, executing |
| // |callback| when completed. |
| // |
| // Only valid to call after a successful Initialize() or Flush(). |
| virtual void Preroll(base::TimeDelta time, |
| const PipelineStatusCB& callback) = 0; |
| |
| // Stop all operations in preparation for being deleted, executing |callback| |
| // when complete. |
| virtual void Stop(const base::Closure& callback) = 0; |
| |
| // Updates the current playback rate. |
| virtual void SetPlaybackRate(float playback_rate) = 0; |
| |
| // Sets the output volume. |
| virtual void SetVolume(float volume) = 0; |
| |
| // Resumes playback after underflow occurs. |
| virtual void ResumeAfterUnderflow() = 0; |
| |
| private: |
| DISALLOW_COPY_AND_ASSIGN(AudioRenderer); |
| }; |
| |
| } // namespace media |
| |
| #endif // MEDIA_BASE_AUDIO_RENDERER_H_ |