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Side by Side Diff: media/audio/audio_parameters.h

Issue 1907973003: media: Move audio_parameters and audio_point to media/base/ (Closed) Base URL: https://chromium.googlesource.com/chromium/src.git@master
Patch Set: rebase Created 4 years, 8 months ago
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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
3 // found in the LICENSE file.
4
5 #ifndef MEDIA_AUDIO_AUDIO_PARAMETERS_H_
6 #define MEDIA_AUDIO_AUDIO_PARAMETERS_H_
7
8 #include <stdint.h>
9 #include <string>
10
11 #include "base/compiler_specific.h"
12 #include "base/time/time.h"
13 #include "build/build_config.h"
14 #include "media/audio/point.h"
15 #include "media/base/audio_bus.h"
16 #include "media/base/channel_layout.h"
17 #include "media/base/media_export.h"
18
19 namespace media {
20
21 // Use a struct-in-struct approach to ensure that we can calculate the required
22 // size as sizeof(Audio{Input,Output}BufferParameters) + #(bytes in audio
23 // buffer) without using packing. Also align Audio{Input,Output}BufferParameters
24 // instead of in Audio{Input,Output}Buffer to be able to calculate size like so.
25 // Use a macro for the alignment value that's the same as
26 // AudioBus::kChannelAlignment, since MSVC doesn't accept the latter to be used.
27 #if defined(OS_WIN)
28 #pragma warning(push)
29 #pragma warning(disable: 4324) // Disable warning for added padding.
30 #endif
31 #define PARAMETERS_ALIGNMENT 16
32 static_assert(AudioBus::kChannelAlignment == PARAMETERS_ALIGNMENT,
33 "Audio buffer parameters struct alignment not same as AudioBus");
34 struct MEDIA_EXPORT ALIGNAS(PARAMETERS_ALIGNMENT) AudioInputBufferParameters {
35 double volume;
36 uint32_t size;
37 uint32_t hardware_delay_bytes;
38 uint32_t id;
39 bool key_pressed;
40 };
41 struct MEDIA_EXPORT ALIGNAS(PARAMETERS_ALIGNMENT) AudioOutputBufferParameters {
42 uint32_t frames_skipped;
43 };
44 #undef PARAMETERS_ALIGNMENT
45 #if defined(OS_WIN)
46 #pragma warning(pop)
47 #endif
48
49 static_assert(sizeof(AudioInputBufferParameters) %
50 AudioBus::kChannelAlignment ==
51 0,
52 "AudioInputBufferParameters not aligned");
53 static_assert(sizeof(AudioOutputBufferParameters) %
54 AudioBus::kChannelAlignment ==
55 0,
56 "AudioOutputBufferParameters not aligned");
57
58 struct MEDIA_EXPORT AudioInputBuffer {
59 AudioInputBufferParameters params;
60 int8_t audio[1];
61 };
62 struct MEDIA_EXPORT AudioOutputBuffer {
63 AudioOutputBufferParameters params;
64 int8_t audio[1];
65 };
66
67 class MEDIA_EXPORT AudioParameters {
68 public:
69 // TODO(miu): Rename this enum to something that correctly reflects its
70 // semantics, such as "TransportScheme."
71 enum Format {
72 AUDIO_PCM_LINEAR = 0, // PCM is 'raw' amplitude samples.
73 AUDIO_PCM_LOW_LATENCY, // Linear PCM, low latency requested.
74 AUDIO_FAKE, // Creates a fake AudioOutputStream object.
75 AUDIO_FORMAT_LAST = AUDIO_FAKE, // Only used for validation of format.
76 };
77
78 enum {
79 // Telephone quality sample rate, mostly for speech-only audio.
80 kTelephoneSampleRate = 8000,
81 // CD sampling rate is 44.1 KHz or conveniently 2x2x3x3x5x5x7x7.
82 kAudioCDSampleRate = 44100,
83 };
84
85 // Bitmasks to determine whether certain platform (typically hardware) audio
86 // effects should be enabled.
87 enum PlatformEffectsMask {
88 NO_EFFECTS = 0x0,
89 ECHO_CANCELLER = 0x1,
90 DUCKING = 0x2, // Enables ducking if the OS supports it.
91 KEYBOARD_MIC = 0x4,
92 HOTWORD = 0x8,
93 };
94
95 AudioParameters();
96 AudioParameters(Format format,
97 ChannelLayout channel_layout,
98 int sample_rate,
99 int bits_per_sample,
100 int frames_per_buffer);
101
102 ~AudioParameters();
103
104 // Re-initializes all members.
105 void Reset(Format format,
106 ChannelLayout channel_layout,
107 int sample_rate,
108 int bits_per_sample,
109 int frames_per_buffer);
110
111 // Checks that all values are in the expected range. All limits are specified
112 // in media::Limits.
113 bool IsValid() const;
114
115 // Returns a human-readable string describing |*this|. For debugging & test
116 // output only.
117 std::string AsHumanReadableString() const;
118
119 // Returns size of audio buffer in bytes.
120 int GetBytesPerBuffer() const;
121
122 // Returns the number of bytes representing one second of audio.
123 int GetBytesPerSecond() const;
124
125 // Returns the number of bytes representing a frame of audio.
126 int GetBytesPerFrame() const;
127
128 // Returns the number of microseconds per frame of audio. Intentionally
129 // reported as a double to surface of partial microseconds per frame, which
130 // is common for many sample rates. Failing to account for these nanoseconds
131 // can lead to audio/video sync drift.
132 double GetMicrosecondsPerFrame() const;
133
134 // Returns the duration of this buffer as calculated from frames_per_buffer()
135 // and sample_rate().
136 base::TimeDelta GetBufferDuration() const;
137
138 // Comparison with other AudioParams.
139 bool Equals(const AudioParameters& other) const;
140
141 void set_format(Format format) { format_ = format; }
142 Format format() const { return format_; }
143
144 // A setter for channel_layout_ is intentionally excluded.
145 ChannelLayout channel_layout() const { return channel_layout_; }
146
147 // The number of channels is usually computed from channel_layout_. Setting
148 // this explictly is only required with CHANNEL_LAYOUT_DISCRETE.
149 void set_channels_for_discrete(int channels) {
150 DCHECK(channel_layout_ == CHANNEL_LAYOUT_DISCRETE ||
151 channels == ChannelLayoutToChannelCount(channel_layout_));
152 channels_ = channels;
153 }
154 int channels() const { return channels_; }
155
156 void set_sample_rate(int sample_rate) { sample_rate_ = sample_rate; }
157 int sample_rate() const { return sample_rate_; }
158
159 void set_bits_per_sample(int bits_per_sample) {
160 bits_per_sample_ = bits_per_sample;
161 }
162 int bits_per_sample() const { return bits_per_sample_; }
163
164 void set_frames_per_buffer(int frames_per_buffer) {
165 frames_per_buffer_ = frames_per_buffer;
166 }
167 int frames_per_buffer() const { return frames_per_buffer_; }
168
169 void set_effects(int effects) { effects_ = effects; }
170 int effects() const { return effects_; }
171
172 void set_mic_positions(const std::vector<Point>& mic_positions) {
173 mic_positions_ = mic_positions;
174 }
175 const std::vector<Point>& mic_positions() const { return mic_positions_; }
176
177 AudioParameters(const AudioParameters&);
178 AudioParameters& operator=(const AudioParameters&);
179
180 // Creates reasonable dummy parameters in case no device is available.
181 static AudioParameters UnavailableDeviceParams();
182
183 private:
184 Format format_; // Format of the stream.
185 ChannelLayout channel_layout_; // Order of surround sound channels.
186 int channels_; // Number of channels. Value set based on
187 // |channel_layout|.
188 int sample_rate_; // Sampling frequency/rate.
189 int bits_per_sample_; // Number of bits per sample.
190 int frames_per_buffer_; // Number of frames in a buffer.
191 int effects_; // Bitmask using PlatformEffectsMask.
192
193 // Microphone positions using Cartesian coordinates:
194 // x: the horizontal dimension, with positive to the right from the camera's
195 // perspective.
196 // y: the depth dimension, with positive forward from the camera's
197 // perspective.
198 // z: the vertical dimension, with positive upwards.
199 //
200 // Usually, the center of the microphone array will be treated as the origin
201 // (often the position of the camera).
202 //
203 // An empty vector indicates unknown positions.
204 std::vector<Point> mic_positions_;
205 };
206
207 // Comparison is useful when AudioParameters is used with std structures.
208 inline bool operator<(const AudioParameters& a, const AudioParameters& b) {
209 if (a.format() != b.format())
210 return a.format() < b.format();
211 if (a.channels() != b.channels())
212 return a.channels() < b.channels();
213 if (a.sample_rate() != b.sample_rate())
214 return a.sample_rate() < b.sample_rate();
215 if (a.bits_per_sample() != b.bits_per_sample())
216 return a.bits_per_sample() < b.bits_per_sample();
217 return a.frames_per_buffer() < b.frames_per_buffer();
218 }
219
220 } // namespace media
221
222 #endif // MEDIA_AUDIO_AUDIO_PARAMETERS_H_
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