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Issue 12316131: Moved AudioUtil static functions to AudioManager interfaces (Closed) Base URL: svn://svn.chromium.org/chrome/trunk/src
Patch Set: made the GetPreferredOutputStreamParameters protected Created 7 years, 9 months ago
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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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101 } else if (bytes_per_sample == 4) { 101 } else if (bytes_per_sample == 4) {
102 AdjustVolume<int32, int64, 0>(reinterpret_cast<int32*>(buf), 102 AdjustVolume<int32, int64, 0>(reinterpret_cast<int32*>(buf),
103 sample_count, 103 sample_count,
104 fixed_volume); 104 fixed_volume);
105 return true; 105 return true;
106 } 106 }
107 } 107 }
108 return false; 108 return false;
109 } 109 }
110 110
111 int GetAudioHardwareSampleRate() {
112 #if defined(OS_MACOSX)
113 // Hardware sample-rate on the Mac can be configured, so we must query.
114 return AUAudioOutputStream::HardwareSampleRate();
115 #elif defined(OS_WIN)
116 if (!CoreAudioUtil::IsSupported()) {
117 // Fall back to Windows Wave implementation on Windows XP or lower
118 // and use 48kHz as default input sample rate.
119 return 48000;
120 }
121
122 // TODO(crogers): tune this rate for best possible WebAudio performance.
123 // WebRTC works well at 48kHz and a buffer size of 480 samples will be used
124 // for this case. Note that exclusive mode is experimental.
125 const CommandLine* cmd_line = CommandLine::ForCurrentProcess();
126 if (cmd_line->HasSwitch(switches::kEnableExclusiveAudio)) {
127 // This sample rate will be combined with a buffer size of 256 samples
128 // (see GetAudioHardwareBufferSize()), which corresponds to an output
129 // delay of ~5.33ms.
130 return 48000;
131 }
132
133 // Hardware sample-rate on Windows can be configured, so we must query.
134 // TODO(henrika): improve possibility to specify an audio endpoint.
135 // Use the default device (same as for Wave) for now to be compatible.
136 return WASAPIAudioOutputStream::HardwareSampleRate();
137 #elif defined(OS_ANDROID)
138 // TODO(leozwang): return native sampling rate on Android.
139 return 16000;
140 #else
141 return 48000;
142 #endif
143 }
144
145 int GetAudioInputHardwareSampleRate(const std::string& device_id) {
146 // TODO(henrika): add support for device selection on all platforms.
147 // Only exists on Windows today.
148 #if defined(OS_MACOSX)
149 return AUAudioInputStream::HardwareSampleRate();
150 #elif defined(OS_WIN)
151 if (!CoreAudioUtil::IsSupported()) {
152 return 48000;
153 }
154 return WASAPIAudioInputStream::HardwareSampleRate(device_id);
155 #elif defined(OS_ANDROID)
156 return 16000;
157 #else
158 // Hardware for Linux is nearly always 48KHz.
159 // TODO(crogers) : return correct value in rare non-48KHz cases.
160 return 48000;
161 #endif
162 }
163
164 size_t GetAudioHardwareBufferSize() {
165 int user_buffer_size = GetUserBufferSize();
166 if (user_buffer_size)
167 return user_buffer_size;
168
169 // The sizes here were determined by experimentation and are roughly
170 // the lowest value (for low latency) that still allowed glitch-free
171 // audio under high loads.
172 //
173 // 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
175 // tuning may be needed.
176 #if defined(OS_MACOSX)
177 return 128;
178 #elif defined(OS_WIN)
179 // TODO(henrika): resolve conflict with GetUserBufferSize().
180 // If the user tries to set a buffer size using GetUserBufferSize() it will
181 // most likely fail since only the native/perfect buffer size is allowed.
182
183 // Buffer size to use when a proper size can't be determined from the system.
184 static const int kFallbackBufferSize = 2048;
185
186 if (!CoreAudioUtil::IsSupported()) {
187 // Fall back to Windows Wave implementation on Windows XP or lower
188 // and assume 48kHz as default sample rate.
189 return kFallbackBufferSize;
190 }
191
192 // TODO(crogers): tune this size to best possible WebAudio performance.
193 // WebRTC always uses 10ms for Windows and does not call this method.
194 // Note that exclusive mode is experimental.
195 const CommandLine* cmd_line = CommandLine::ForCurrentProcess();
196 if (cmd_line->HasSwitch(switches::kEnableExclusiveAudio)) {
197 return 256;
198 }
199
200 AudioParameters params;
201 HRESULT hr = CoreAudioUtil::GetPreferredAudioParameters(eRender, eConsole,
202 &params);
203 return FAILED(hr) ? kFallbackBufferSize : params.frames_per_buffer();
204 #elif defined(OS_LINUX)
205 return 512;
206 #else
207 return 2048;
208 #endif
209 }
210
211 ChannelLayout GetAudioInputHardwareChannelLayout(const std::string& device_id) {
212 // TODO(henrika): add support for device selection on all platforms.
213 // Only exists on Windows today.
214 #if defined(OS_MACOSX)
215 return CHANNEL_LAYOUT_MONO;
216 #elif defined(OS_WIN)
217 if (!CoreAudioUtil::IsSupported()) {
218 // Fall back to Windows Wave implementation on Windows XP or lower and
219 // use stereo by default.
220 return CHANNEL_LAYOUT_STEREO;
221 }
222 return WASAPIAudioInputStream::HardwareChannelCount(device_id) == 1 ?
223 CHANNEL_LAYOUT_MONO : CHANNEL_LAYOUT_STEREO;
224 #else
225 return CHANNEL_LAYOUT_STEREO;
226 #endif
227 }
228
229 // Computes a buffer size based on the given |sample_rate|. Must be used in 111 // Computes a buffer size based on the given |sample_rate|. Must be used in
230 // conjunction with AUDIO_PCM_LINEAR. 112 // conjunction with AUDIO_PCM_LINEAR.
231 size_t GetHighLatencyOutputBufferSize(int sample_rate) { 113 size_t GetHighLatencyOutputBufferSize(int sample_rate) {
232 int user_buffer_size = GetUserBufferSize(); 114 int user_buffer_size = GetUserBufferSize();
233 if (user_buffer_size) 115 if (user_buffer_size)
234 return user_buffer_size; 116 return user_buffer_size;
235 117
236 // TODO(vrk/crogers): The buffer sizes that this function computes is probably 118 // TODO(vrk/crogers): The buffer sizes that this function computes is probably
237 // overly conservative. However, reducing the buffer size to 2048-8192 bytes 119 // overly conservative. However, reducing the buffer size to 2048-8192 bytes
238 // caused crbug.com/108396. This computation should be revisited while making 120 // caused crbug.com/108396. This computation should be revisited while making
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278 // out performance was degraded compared to XP. 160 // out performance was degraded compared to XP.
279 // - The regression was fixed in Windows 7 and most configurations will work 161 // - The regression was fixed in Windows 7 and most configurations will work
280 // with 2, but some (e.g., some Sound Blasters) still need 3. 162 // with 2, but some (e.g., some Sound Blasters) still need 3.
281 // - Some XP configurations (even multi-processor ones) also need 3. 163 // - Some XP configurations (even multi-processor ones) also need 3.
282 return (base::win::GetVersion() == base::win::VERSION_VISTA) ? 4 : 3; 164 return (base::win::GetVersion() == base::win::VERSION_VISTA) ? 4 : 3;
283 } 165 }
284 166
285 #endif 167 #endif
286 168
287 } // namespace media 169 } // namespace media
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