Fix for browser_plugin_host_browsertest when embedder is not yet available.
[chromium-blink-merge.git] / media / base / audio_renderer_sink.h
blobb2f4ba0a90201b6420106fde54faa8ebcf7437bf
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_SINK_H_
6 #define MEDIA_BASE_AUDIO_RENDERER_SINK_H_
8 #include <vector>
9 #include "base/basictypes.h"
10 #include "base/logging.h"
11 #include "base/memory/ref_counted.h"
12 #include "media/audio/audio_parameters.h"
13 #include "media/base/audio_bus.h"
14 #include "media/base/media_export.h"
16 namespace media {
18 // AudioRendererSink is an interface representing the end-point for
19 // rendered audio. An implementation is expected to
20 // periodically call Render() on a callback object.
22 class AudioRendererSink
23 : public base::RefCountedThreadSafe<media::AudioRendererSink> {
24 public:
25 class RenderCallback {
26 public:
27 // Attempts to completely fill all channels of |dest|, returns actual
28 // number of frames filled.
29 virtual int Render(AudioBus* dest, int audio_delay_milliseconds) = 0;
31 // Synchronized audio I/O - see InitializeIO() below.
32 virtual void RenderIO(AudioBus* source,
33 AudioBus* dest,
34 int audio_delay_milliseconds) {}
36 // Signals an error has occurred.
37 virtual void OnRenderError() = 0;
39 protected:
40 virtual ~RenderCallback() {}
43 // Sets important information about the audio stream format.
44 // It must be called before any of the other methods.
45 virtual void Initialize(const AudioParameters& params,
46 RenderCallback* callback) = 0;
48 // Starts audio playback.
49 virtual void Start() = 0;
51 // Stops audio playback.
52 virtual void Stop() = 0;
54 // Pauses playback.
55 virtual void Pause() = 0;
57 // Resumes playback after calling Pause().
58 virtual void Play() = 0;
60 // Sets the playback volume, with range [0.0, 1.0] inclusive.
61 // Returns |true| on success.
62 virtual bool SetVolume(double volume) = 0;
64 protected:
65 friend class base::RefCountedThreadSafe<AudioRendererSink>;
66 virtual ~AudioRendererSink() {}
69 } // namespace media
71 #endif // MEDIA_BASE_AUDIO_RENDERER_SINK_H_