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Side by Side Diff: media/base/audio_hardware_config.cc

Issue 2067863003: Mixing audio with different latency requirements (Closed) Base URL: https://chromium.googlesource.com/chromium/src.git@master
Patch Set: fixing bot redness Created 4 years, 5 months ago
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1 // Copyright (c) 2013 The Chromium Authors. All rights reserved. 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 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 "media/base/audio_hardware_config.h" 5 #include "media/base/audio_hardware_config.h"
6 6
7 #include <stdint.h> 7 #include <stdint.h>
8 8
9 #include <algorithm> 9 #include <algorithm>
10 #include <cmath> 10 #include <cmath>
11 11
12 #include "base/logging.h" 12 #include "base/logging.h"
13 #include "build/build_config.h" 13 #include "build/build_config.h"
14 14
15 using base::AutoLock; 15 using base::AutoLock;
16 using media::AudioParameters; 16 using media::AudioParameters;
17 17
18 namespace media { 18 namespace media {
19 19
20 #if !defined(OS_WIN)
21 // Taken from "Bit Twiddling Hacks"
22 // http://graphics.stanford.edu/~seander/bithacks.html#RoundUpPowerOf2
23 static uint32_t RoundUpToPowerOfTwo(uint32_t v) {
24 v--;
25 v |= v >> 1;
26 v |= v >> 2;
27 v |= v >> 4;
28 v |= v >> 8;
29 v |= v >> 16;
30 v++;
31 return v;
32 }
33 #endif
34
35 AudioHardwareConfig::AudioHardwareConfig( 20 AudioHardwareConfig::AudioHardwareConfig(
36 const AudioParameters& input_params, 21 const AudioParameters& input_params,
37 const AudioParameters& output_params) 22 const AudioParameters& output_params)
38 : input_params_(input_params), 23 : input_params_(input_params),
39 output_params_(output_params) {} 24 output_params_(output_params) {}
40 25
41 AudioHardwareConfig::~AudioHardwareConfig() {} 26 AudioHardwareConfig::~AudioHardwareConfig() {}
42 27
43 int AudioHardwareConfig::GetOutputBufferSize() const { 28 int AudioHardwareConfig::GetOutputBufferSize() const {
44 AutoLock auto_lock(config_lock_); 29 AutoLock auto_lock(config_lock_);
(...skipping 47 matching lines...) Expand 10 before | Expand all | Expand 10 after
92 AutoLock auto_lock(config_lock_); 77 AutoLock auto_lock(config_lock_);
93 input_params_ = input_params; 78 input_params_ = input_params;
94 } 79 }
95 80
96 void AudioHardwareConfig::UpdateOutputConfig( 81 void AudioHardwareConfig::UpdateOutputConfig(
97 const AudioParameters& output_params) { 82 const AudioParameters& output_params) {
98 AutoLock auto_lock(config_lock_); 83 AutoLock auto_lock(config_lock_);
99 output_params_ = output_params; 84 output_params_ = output_params;
100 } 85 }
101 86
102 // static
103 int AudioHardwareConfig::GetHighLatencyBufferSize(int sample_rate,
104 int buffer_size) {
105 // Empirically, we consider 20ms of samples to be high latency.
106 const double twenty_ms_size = 2.0 * sample_rate / 100;
107
108 #if defined(OS_WIN)
109 buffer_size = std::max(buffer_size, 1);
110
111 // Windows doesn't use power of two buffer sizes, so we should always round up
112 // to the nearest multiple of the output buffer size.
113 const int high_latency_buffer_size =
114 std::ceil(twenty_ms_size / buffer_size) * buffer_size;
115 #else
116 // On other platforms use the nearest higher power of two buffer size. For a
117 // given sample rate, this works out to:
118 //
119 // <= 3200 : 64
120 // <= 6400 : 128
121 // <= 12800 : 256
122 // <= 25600 : 512
123 // <= 51200 : 1024
124 // <= 102400 : 2048
125 // <= 204800 : 4096
126 //
127 // On Linux, the minimum hardware buffer size is 512, so the lower calculated
128 // values are unused. OSX may have a value as low as 128.
129 const int high_latency_buffer_size = RoundUpToPowerOfTwo(twenty_ms_size);
130 #endif // defined(OS_WIN)
131
132 return std::max(buffer_size, high_latency_buffer_size);
133 }
134
135 int AudioHardwareConfig::GetHighLatencyBufferSize() const {
136 AutoLock auto_lock(config_lock_);
137 return GetHighLatencyBufferSize(output_params_.sample_rate(),
138 output_params_.frames_per_buffer());
139 }
140
141 } // namespace media 87 } // namespace media
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