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.
5 #ifndef MEDIA_BASE_AUDIO_RENDERER_H_
6 #define MEDIA_BASE_AUDIO_RENDERER_H_
8 #include "base/callback.h"
9 #include "base/memory/ref_counted.h"
10 #include "base/time/time.h"
11 #include "media/base/media_export.h"
12 #include "media/base/pipeline_status.h"
18 class MEDIA_EXPORT AudioRenderer {
20 // First parameter is the current time that has been rendered.
21 // Second parameter is the maximum time value that the clock cannot exceed.
22 typedef base::Callback<void(base::TimeDelta, base::TimeDelta)> TimeCB;
25 virtual ~AudioRenderer();
27 // Initialize an AudioRenderer with |stream|, executing |init_cb| upon
30 // |statistics_cb| is executed periodically with audio rendering stats.
32 // |underflow_cb| is executed when the renderer runs out of data to pass to
33 // the audio card during playback. ResumeAfterUnderflow() must be called
34 // to resume playback. Pause(), Preroll(), or Stop() cancels the underflow
37 // |time_cb| is executed whenever time has advanced by way of audio rendering.
39 // |ended_cb| is executed when audio rendering has reached the end of stream.
41 // |disabled_cb| is executed when audio rendering has been disabled due to
42 // external factors (i.e., device was removed). |time_cb| will no longer be
43 // executed. TODO(scherkus): this might not be needed http://crbug.com/234708
45 // |error_cb| is executed if an error was encountered.
46 virtual void Initialize(DemuxerStream* stream,
47 const PipelineStatusCB& init_cb,
48 const StatisticsCB& statistics_cb,
49 const base::Closure& underflow_cb,
50 const TimeCB& time_cb,
51 const base::Closure& ended_cb,
52 const base::Closure& disabled_cb,
53 const PipelineStatusCB& error_cb) = 0;
55 // Start audio decoding and rendering at the current playback rate, executing
56 // |callback| when playback is underway.
57 virtual void Play(const base::Closure& callback) = 0;
59 // Temporarily suspend decoding and rendering audio, executing |callback| when
60 // playback has been suspended.
61 virtual void Pause(const base::Closure& callback) = 0;
63 // Discard any audio data, executing |callback| when completed.
64 virtual void Flush(const base::Closure& callback) = 0;
66 // Start prerolling audio data for samples starting at |time|, executing
67 // |callback| when completed.
69 // Only valid to call after a successful Initialize() or Flush().
70 virtual void Preroll(base::TimeDelta time,
71 const PipelineStatusCB& callback) = 0;
73 // Stop all operations in preparation for being deleted, executing |callback|
75 virtual void Stop(const base::Closure& callback) = 0;
77 // Updates the current playback rate.
78 virtual void SetPlaybackRate(float playback_rate) = 0;
80 // Sets the output volume.
81 virtual void SetVolume(float volume) = 0;
83 // Resumes playback after underflow occurs.
84 virtual void ResumeAfterUnderflow() = 0;
87 DISALLOW_COPY_AND_ASSIGN(AudioRenderer);
92 #endif // MEDIA_BASE_AUDIO_RENDERER_H_