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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 // Software adjust volume of samples, allows each audio stream its own | 5 // Software adjust volume of samples, allows each audio stream its own |
6 // volume without impacting master volume for chrome and other applications. | 6 // volume without impacting master volume for chrome and other applications. |
7 | 7 |
8 // Implemented as templates to allow 8, 16 and 32 bit implementations. | 8 // Implemented as templates to allow 8, 16 and 32 bit implementations. |
9 // 8 bit is unsigned and biased by 128. | 9 // 8 bit is unsigned and biased by 128. |
10 | 10 |
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125 const CommandLine* cmd_line = CommandLine::ForCurrentProcess(); | 125 const CommandLine* cmd_line = CommandLine::ForCurrentProcess(); |
126 if (cmd_line->HasSwitch(switches::kEnableExclusiveAudio)) { | 126 if (cmd_line->HasSwitch(switches::kEnableExclusiveAudio)) { |
127 // This sample rate will be combined with a buffer size of 256 samples | 127 // This sample rate will be combined with a buffer size of 256 samples |
128 // (see GetAudioHardwareBufferSize()), which corresponds to an output | 128 // (see GetAudioHardwareBufferSize()), which corresponds to an output |
129 // delay of ~5.33ms. | 129 // delay of ~5.33ms. |
130 return 48000; | 130 return 48000; |
131 } | 131 } |
132 | 132 |
133 // Hardware sample-rate on Windows can be configured, so we must query. | 133 // Hardware sample-rate on Windows can be configured, so we must query. |
134 // TODO(henrika): improve possibility to specify an audio endpoint. | 134 // TODO(henrika): improve possibility to specify an audio endpoint. |
135 // Use the default device (same as for Wave) for now to be compatible | 135 // Use the default device (same as for Wave) for now to be compatible. |
136 // or possibly remove the ERole argument completely until it is in use. | 136 return WASAPIAudioOutputStream::HardwareSampleRate(); |
137 return WASAPIAudioOutputStream::HardwareSampleRate(eConsole); | |
138 #elif defined(OS_ANDROID) | 137 #elif defined(OS_ANDROID) |
139 return 16000; | 138 return 16000; |
140 #else | 139 #else |
141 // Hardware for Linux is nearly always 48KHz. | 140 // Hardware for Linux is nearly always 48KHz. |
142 // TODO(crogers) : return correct value in rare non-48KHz cases. | 141 // TODO(crogers) : return correct value in rare non-48KHz cases. |
143 return 48000; | 142 return 48000; |
144 #endif | 143 #endif |
145 } | 144 } |
146 | 145 |
147 int GetAudioInputHardwareSampleRate(const std::string& device_id) { | 146 int GetAudioInputHardwareSampleRate(const std::string& device_id) { |
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169 // The sizes here were determined by experimentation and are roughly | 168 // The sizes here were determined by experimentation and are roughly |
170 // the lowest value (for low latency) that still allowed glitch-free | 169 // the lowest value (for low latency) that still allowed glitch-free |
171 // audio under high loads. | 170 // audio under high loads. |
172 // | 171 // |
173 // For Mac OS X and Windows the chromium audio backend uses a low-latency | 172 // For Mac OS X and Windows the chromium audio backend uses a low-latency |
174 // Core Audio API, so a low buffer size is possible. For Linux, further | 173 // Core Audio API, so a low buffer size is possible. For Linux, further |
175 // tuning may be needed. | 174 // tuning may be needed. |
176 #if defined(OS_MACOSX) | 175 #if defined(OS_MACOSX) |
177 return 128; | 176 return 128; |
178 #elif defined(OS_WIN) | 177 #elif defined(OS_WIN) |
178 // TODO(henrika): resolve conflict with GetUserBufferSize(). | |
179 // If the user tries to set a buffer size using GetUserBufferSize() it will | |
180 // most likely fail since only the native/perfect buffer size is allowed. | |
181 | |
179 // Buffer size to use when a proper size can't be determined from the system. | 182 // Buffer size to use when a proper size can't be determined from the system. |
180 static const int kFallbackBufferSize = 2048; | 183 static const int kFallbackBufferSize = 4096; |
DaleCurtis
2013/02/02 00:19:51
I just changed this to 2048 in https://codereview.
henrika (OOO until Aug 14)
2013/02/04 08:25:38
Cool. I will of course not mess that up. Now using
| |
181 | 184 |
182 if (!CoreAudioUtil::IsSupported()) { | 185 if (!CoreAudioUtil::IsSupported()) { |
183 // Fall back to Windows Wave implementation on Windows XP or lower | 186 // Fall back to Windows Wave implementation on Windows XP or lower |
184 // and assume 48kHz as default sample rate. | 187 // and assume 48kHz as default sample rate. |
185 return kFallbackBufferSize; | 188 return kFallbackBufferSize; |
186 } | 189 } |
187 | 190 |
188 // TODO(crogers): tune this size to best possible WebAudio performance. | 191 // TODO(crogers): tune this size to best possible WebAudio performance. |
189 // WebRTC always uses 10ms for Windows and does not call this method. | 192 // WebRTC always uses 10ms for Windows and does not call this method. |
190 // Note that exclusive mode is experimental. | 193 // Note that exclusive mode is experimental. |
191 const CommandLine* cmd_line = CommandLine::ForCurrentProcess(); | 194 const CommandLine* cmd_line = CommandLine::ForCurrentProcess(); |
192 if (cmd_line->HasSwitch(switches::kEnableExclusiveAudio)) { | 195 if (cmd_line->HasSwitch(switches::kEnableExclusiveAudio)) { |
193 return 256; | 196 return 256; |
194 } | 197 } |
195 | 198 |
196 // TODO(henrika): remove when the --enable-webaudio-input flag is no longer | 199 AudioParameters params; |
197 // utilized. | 200 HRESULT hr = CoreAudioUtil::GetPreferredAudioParameters(eRender, eConsole, |
198 if (cmd_line->HasSwitch(switches::kEnableWebAudioInput)) { | 201 ¶ms); |
199 AudioParameters params; | 202 return FAILED(hr) ? kFallbackBufferSize : params.frames_per_buffer(); |
200 HRESULT hr = CoreAudioUtil::GetPreferredAudioParameters(eRender, eConsole, | |
201 ¶ms); | |
202 return FAILED(hr) ? kFallbackBufferSize : params.frames_per_buffer(); | |
203 } | |
204 | |
205 // This call must be done on a COM thread configured as MTA. | |
206 // TODO(tommi): http://code.google.com/p/chromium/issues/detail?id=103835. | |
207 int mixing_sample_rate = | |
208 WASAPIAudioOutputStream::HardwareSampleRate(eConsole); | |
209 | |
210 // Windows will return a sample rate of 0 when no audio output is available | |
211 // (i.e. via RemoteDesktop with remote audio disabled), but we should never | |
212 // return a buffer size of zero. | |
213 if (mixing_sample_rate == 0) | |
214 return kFallbackBufferSize; | |
215 | |
216 // Use different buffer sizes depening on the sample rate . The existing | |
217 // WASAPI implementation is tuned to provide the most stable callback | |
218 // sequence using these combinations. | |
219 if (mixing_sample_rate % 11025 == 0) | |
220 // Use buffer size of ~10.15873 ms. | |
221 return (112 * (mixing_sample_rate / 11025)); | |
222 | |
223 if (mixing_sample_rate % 8000 == 0) | |
224 // Use buffer size of 10ms. | |
225 return (80 * (mixing_sample_rate / 8000)); | |
226 | |
227 // Ensure we always return a buffer size which is somewhat appropriate. | |
228 LOG(ERROR) << "Unknown sample rate " << mixing_sample_rate << " detected."; | |
229 if (mixing_sample_rate > limits::kMinSampleRate) | |
230 return (mixing_sample_rate / 100); | |
231 return kFallbackBufferSize; | |
232 #else | 203 #else |
233 return 2048; | 204 return 2048; |
234 #endif | 205 #endif |
235 } | 206 } |
236 | 207 |
237 ChannelLayout GetAudioInputHardwareChannelLayout(const std::string& device_id) { | 208 ChannelLayout GetAudioInputHardwareChannelLayout(const std::string& device_id) { |
238 // TODO(henrika): add support for device selection on all platforms. | 209 // TODO(henrika): add support for device selection on all platforms. |
239 // Only exists on Windows today. | 210 // Only exists on Windows today. |
240 #if defined(OS_MACOSX) | 211 #if defined(OS_MACOSX) |
241 return CHANNEL_LAYOUT_MONO; | 212 return CHANNEL_LAYOUT_MONO; |
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296 // out performance was degraded compared to XP. | 267 // out performance was degraded compared to XP. |
297 // - The regression was fixed in Windows 7 and most configurations will work | 268 // - The regression was fixed in Windows 7 and most configurations will work |
298 // with 2, but some (e.g., some Sound Blasters) still need 3. | 269 // with 2, but some (e.g., some Sound Blasters) still need 3. |
299 // - Some XP configurations (even multi-processor ones) also need 3. | 270 // - Some XP configurations (even multi-processor ones) also need 3. |
300 return (base::win::GetVersion() == base::win::VERSION_VISTA) ? 4 : 3; | 271 return (base::win::GetVersion() == base::win::VERSION_VISTA) ? 4 : 3; |
301 } | 272 } |
302 | 273 |
303 #endif | 274 #endif |
304 | 275 |
305 } // namespace media | 276 } // namespace media |
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