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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 #include <CoreAudio/AudioHardware.h> | 5 #include <CoreAudio/AudioHardware.h> |
6 | 6 |
7 #include <string> | 7 #include <string> |
8 | 8 |
9 #include "base/command_line.h" | 9 #include "base/command_line.h" |
10 #include "base/mac/mac_logging.h" | 10 #include "base/mac/mac_logging.h" |
11 #include "base/mac/scoped_cftyperef.h" | 11 #include "base/mac/scoped_cftyperef.h" |
12 #include "base/sys_string_conversions.h" | 12 #include "base/sys_string_conversions.h" |
13 #include "media/audio/audio_util.h" | |
13 #include "media/audio/mac/audio_input_mac.h" | 14 #include "media/audio/mac/audio_input_mac.h" |
14 #include "media/audio/mac/audio_low_latency_input_mac.h" | 15 #include "media/audio/mac/audio_low_latency_input_mac.h" |
15 #include "media/audio/mac/audio_low_latency_output_mac.h" | 16 #include "media/audio/mac/audio_low_latency_output_mac.h" |
16 #include "media/audio/mac/audio_manager_mac.h" | 17 #include "media/audio/mac/audio_manager_mac.h" |
17 #include "media/audio/mac/audio_output_mac.h" | 18 #include "media/audio/mac/audio_output_mac.h" |
18 #include "media/audio/mac/audio_synchronized_mac.h" | 19 #include "media/audio/mac/audio_synchronized_mac.h" |
19 #include "media/audio/mac/audio_unified_mac.h" | 20 #include "media/audio/mac/audio_unified_mac.h" |
20 #include "media/base/limits.h" | 21 #include "media/base/limits.h" |
21 #include "media/base/media_switches.h" | 22 #include "media/base/media_switches.h" |
22 | 23 |
23 namespace media { | 24 namespace media { |
24 | 25 |
25 // Maximum number of output streams that can be open simultaneously. | 26 // Maximum number of output streams that can be open simultaneously. |
26 static const int kMaxOutputStreams = 50; | 27 static const int kMaxOutputStreams = 50; |
27 | 28 |
29 // Maximum buffer size CoreAudio can support. | |
30 static const int kMaxBufferSize = 2047; | |
DaleCurtis
2012/10/01 17:37:36
Add some comment about low latency specifically. M
no longer working on chromium
2012/10/02 08:06:22
Done.
| |
31 | |
28 static bool HasAudioHardware(AudioObjectPropertySelector selector) { | 32 static bool HasAudioHardware(AudioObjectPropertySelector selector) { |
29 AudioDeviceID output_device_id = kAudioObjectUnknown; | 33 AudioDeviceID output_device_id = kAudioObjectUnknown; |
30 const AudioObjectPropertyAddress property_address = { | 34 const AudioObjectPropertyAddress property_address = { |
31 selector, | 35 selector, |
32 kAudioObjectPropertyScopeGlobal, // mScope | 36 kAudioObjectPropertyScopeGlobal, // mScope |
33 kAudioObjectPropertyElementMaster // mElement | 37 kAudioObjectPropertyElementMaster // mElement |
34 }; | 38 }; |
35 UInt32 output_device_id_size = static_cast<UInt32>(sizeof(output_device_id)); | 39 UInt32 output_device_id_size = static_cast<UInt32>(sizeof(output_device_id)); |
36 OSStatus err = AudioObjectGetPropertyData(kAudioObjectSystemObject, | 40 OSStatus err = AudioObjectGetPropertyData(kAudioObjectSystemObject, |
37 &property_address, | 41 &property_address, |
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326 if (audio_device_id != kAudioObjectUnknown) | 330 if (audio_device_id != kAudioObjectUnknown) |
327 stream = new AUAudioInputStream(this, params, audio_device_id); | 331 stream = new AUAudioInputStream(this, params, audio_device_id); |
328 | 332 |
329 return stream; | 333 return stream; |
330 } | 334 } |
331 | 335 |
332 AudioManager* CreateAudioManager() { | 336 AudioManager* CreateAudioManager() { |
333 return new AudioManagerMac(); | 337 return new AudioManagerMac(); |
334 } | 338 } |
335 | 339 |
340 AudioParameters AudioManagerMac::GetPreferredLowLatencyOutputStreamParameters( | |
341 const AudioParameters& params) { | |
342 // Applications should use their own preferred buffer size when no resampler | |
343 // is needed, and Apple CoreAudio can accept any buffer size up to 2047. | |
344 int native_sample_rate = GetAudioHardwareSampleRate(); | |
345 int buffer_size = GetAudioHardwareBufferSize(); | |
346 if (native_sample_rate == params.sample_rate() && | |
347 params.frames_per_buffer() <= kMaxBufferSize) { | |
348 buffer_size = params.frames_per_buffer(); | |
349 } | |
350 | |
351 return AudioParameters(AudioParameters::AUDIO_PCM_LOW_LATENCY, | |
352 params.channel_layout(), | |
353 native_sample_rate, | |
354 16, | |
355 buffer_size); | |
356 } | |
357 | |
336 } // namespace media | 358 } // namespace media |
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