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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | 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 | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #ifndef MEDIA_AUDIO_AUDIO_OUTPUT_RESAMPLER_H_ | 5 #ifndef MEDIA_AUDIO_AUDIO_OUTPUT_RESAMPLER_H_ |
6 #define MEDIA_AUDIO_AUDIO_OUTPUT_RESAMPLER_H_ | 6 #define MEDIA_AUDIO_AUDIO_OUTPUT_RESAMPLER_H_ |
7 | 7 |
8 #include <map> | 8 #include <map> |
9 | 9 |
10 #include "base/basictypes.h" | 10 #include "base/basictypes.h" |
11 #include "base/memory/ref_counted.h" | 11 #include "base/memory/ref_counted.h" |
12 #include "base/time/time.h" | 12 #include "base/time/time.h" |
13 #include "media/audio/audio_io.h" | 13 #include "media/audio/audio_io.h" |
14 #include "media/audio/audio_manager.h" | 14 #include "media/audio/audio_manager.h" |
15 #include "media/audio/audio_output_dispatcher.h" | 15 #include "media/audio/audio_output_dispatcher.h" |
16 #include "media/audio/audio_parameters.h" | 16 #include "media/audio/audio_parameters.h" |
17 | 17 |
18 namespace media { | 18 namespace media { |
19 | 19 |
20 class OnMoreDataConverter; | 20 class OnMoreDataConverter; |
21 | 21 |
22 // AudioOutputResampler is a browser-side resampling and buffering solution | 22 // AudioOutputResampler is a browser-side resampling and buffering solution |
23 // which ensures audio data is always output at given parameters. See the | 23 // which ensures audio data is always output at given parameters. See the |
24 // AudioConverter class for details on the conversion process. | 24 // AudioConverter class for details on the conversion process. |
25 // | 25 // |
26 // AOR works by intercepting the AudioSourceCallback provided to StartStream() | 26 // AOR works by intercepting the AudioSourceCallback provided to StartStream() |
27 // and redirecting it through an AudioConverter instance. AudioBuffersState is | 27 // and redirecting it through an AudioConverter instance. |total_bytes_delay| |
28 // adjusted for buffer delay caused by the conversion process. | 28 // is adjusted for buffer delay caused by the conversion process. |
29 // | 29 // |
30 // AOR will automatically fall back from AUDIO_PCM_LOW_LATENCY to | 30 // AOR will automatically fall back from AUDIO_PCM_LOW_LATENCY to |
31 // AUDIO_PCM_LINEAR if the output device fails to open at the requested output | 31 // AUDIO_PCM_LINEAR if the output device fails to open at the requested output |
32 // parameters. | 32 // parameters. |
33 // | 33 // |
34 // TODO(dalecurtis): Ideally the low latency path will be as reliable as the | 34 // TODO(dalecurtis): Ideally the low latency path will be as reliable as the |
35 // high latency path once we have channel mixing and support querying for the | 35 // high latency path once we have channel mixing and support querying for the |
36 // hardware's configured bit depth. Monitor the UMA stats for fallback and | 36 // hardware's configured bit depth. Monitor the UMA stats for fallback and |
37 // remove fallback support once it's stable. http://crbug.com/148418 | 37 // remove fallback support once it's stable. http://crbug.com/148418 |
38 class MEDIA_EXPORT AudioOutputResampler : public AudioOutputDispatcher { | 38 class MEDIA_EXPORT AudioOutputResampler : public AudioOutputDispatcher { |
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81 // Whether any streams have been opened through |dispatcher_|, if so we can't | 81 // Whether any streams have been opened through |dispatcher_|, if so we can't |
82 // fallback on future OpenStream() failures. | 82 // fallback on future OpenStream() failures. |
83 bool streams_opened_; | 83 bool streams_opened_; |
84 | 84 |
85 DISALLOW_COPY_AND_ASSIGN(AudioOutputResampler); | 85 DISALLOW_COPY_AND_ASSIGN(AudioOutputResampler); |
86 }; | 86 }; |
87 | 87 |
88 } // namespace media | 88 } // namespace media |
89 | 89 |
90 #endif // MEDIA_AUDIO_AUDIO_OUTPUT_RESAMPLER_H_ | 90 #endif // MEDIA_AUDIO_AUDIO_OUTPUT_RESAMPLER_H_ |
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