1 // Copyright (c) 2013 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 #include "media/base/audio_hardware_config.h"
9 #include "base/logging.h"
10 #include "build/build_config.h"
13 using media::AudioParameters;
17 #if defined(OS_LINUX) || defined(OS_MACOSX)
18 #define HIGH_LATENCY_AUDIO_SUPPORT 1
21 #if defined(HIGH_LATENCY_AUDIO_SUPPORT)
22 // Taken from "Bit Twiddling Hacks"
23 // http://graphics.stanford.edu/~seander/bithacks.html#RoundUpPowerOf2
24 static uint32_t RoundUpToPowerOfTwo(uint32_t v) {
36 AudioHardwareConfig::AudioHardwareConfig(
37 const AudioParameters& input_params,
38 const AudioParameters& output_params)
39 : input_params_(input_params),
40 output_params_(output_params) {}
42 AudioHardwareConfig::~AudioHardwareConfig() {}
44 int AudioHardwareConfig::GetOutputBufferSize() const {
45 AutoLock auto_lock(config_lock_);
46 return output_params_.frames_per_buffer();
49 int AudioHardwareConfig::GetOutputSampleRate() const {
50 AutoLock auto_lock(config_lock_);
51 return output_params_.sample_rate();
54 ChannelLayout AudioHardwareConfig::GetOutputChannelLayout() const {
55 AutoLock auto_lock(config_lock_);
56 return output_params_.channel_layout();
59 int AudioHardwareConfig::GetOutputChannels() const {
60 AutoLock auto_lock(config_lock_);
61 return output_params_.channels();
64 int AudioHardwareConfig::GetInputSampleRate() const {
65 AutoLock auto_lock(config_lock_);
66 return input_params_.sample_rate();
69 ChannelLayout AudioHardwareConfig::GetInputChannelLayout() const {
70 AutoLock auto_lock(config_lock_);
71 return input_params_.channel_layout();
74 int AudioHardwareConfig::GetInputChannels() const {
75 AutoLock auto_lock(config_lock_);
76 return input_params_.channels();
79 media::AudioParameters
80 AudioHardwareConfig::GetInputConfig() const {
81 AutoLock auto_lock(config_lock_);
85 media::AudioParameters
86 AudioHardwareConfig::GetOutputConfig() const {
87 AutoLock auto_lock(config_lock_);
88 return output_params_;
91 void AudioHardwareConfig::UpdateInputConfig(
92 const AudioParameters& input_params) {
93 AutoLock auto_lock(config_lock_);
94 input_params_ = input_params;
97 void AudioHardwareConfig::UpdateOutputConfig(
98 const AudioParameters& output_params) {
99 AutoLock auto_lock(config_lock_);
100 output_params_ = output_params;
103 int AudioHardwareConfig::GetHighLatencyBufferSize() const {
104 AutoLock auto_lock(config_lock_);
105 #if defined(HIGH_LATENCY_AUDIO_SUPPORT)
106 // Empirically, use the nearest higher power of two buffer size corresponding
107 // to 20 ms worth of samples. For a given sample rate, this works out to:
117 // On Linux, the minimum hardware buffer size is 512, so the lower calculated
118 // values are unused. OSX may have a value as low as 128. Windows is device
119 // dependent but will generally be sample_rate() / 100.
120 const int high_latency_buffer_size =
121 RoundUpToPowerOfTwo(2 * output_params_.sample_rate() / 100);
122 return std::max(output_params_.frames_per_buffer(), high_latency_buffer_size);
124 return output_params_.frames_per_buffer();