channel_layout.h (5123B)
1 /* 2 * Copyright (c) 2019 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #ifndef API_AUDIO_CHANNEL_LAYOUT_H_ 12 #define API_AUDIO_CHANNEL_LAYOUT_H_ 13 14 namespace webrtc { 15 16 // This file is derived from Chromium's base/channel_layout.h. 17 18 // Enumerates the various representations of the ordering of audio channels. 19 // Logged to UMA, so never reuse a value, always add new/greater ones! 20 enum ChannelLayout { 21 CHANNEL_LAYOUT_NONE = 0, 22 CHANNEL_LAYOUT_UNSUPPORTED = 1, 23 24 // Front C 25 CHANNEL_LAYOUT_MONO = 2, 26 27 // Front L, Front R 28 CHANNEL_LAYOUT_STEREO = 3, 29 30 // Front L, Front R, Back C 31 CHANNEL_LAYOUT_2_1 = 4, 32 33 // Front L, Front R, Front C 34 CHANNEL_LAYOUT_SURROUND = 5, 35 36 // Front L, Front R, Front C, Back C 37 CHANNEL_LAYOUT_4_0 = 6, 38 39 // Front L, Front R, Side L, Side R 40 CHANNEL_LAYOUT_2_2 = 7, 41 42 // Front L, Front R, Back L, Back R 43 CHANNEL_LAYOUT_QUAD = 8, 44 45 // Front L, Front R, Front C, Side L, Side R 46 CHANNEL_LAYOUT_5_0 = 9, 47 48 // Front L, Front R, Front C, LFE, Side L, Side R 49 CHANNEL_LAYOUT_5_1 = 10, 50 51 // Front L, Front R, Front C, Back L, Back R 52 CHANNEL_LAYOUT_5_0_BACK = 11, 53 54 // Front L, Front R, Front C, LFE, Back L, Back R 55 CHANNEL_LAYOUT_5_1_BACK = 12, 56 57 // Front L, Front R, Front C, Side L, Side R, Back L, Back R 58 CHANNEL_LAYOUT_7_0 = 13, 59 60 // Front L, Front R, Front C, LFE, Side L, Side R, Back L, Back R 61 CHANNEL_LAYOUT_7_1 = 14, 62 63 // Front L, Front R, Front C, LFE, Side L, Side R, Front LofC, Front RofC 64 CHANNEL_LAYOUT_7_1_WIDE = 15, 65 66 // Stereo L, Stereo R 67 CHANNEL_LAYOUT_STEREO_DOWNMIX = 16, 68 69 // Stereo L, Stereo R, LFE 70 CHANNEL_LAYOUT_2POINT1 = 17, 71 72 // Stereo L, Stereo R, Front C, LFE 73 CHANNEL_LAYOUT_3_1 = 18, 74 75 // Stereo L, Stereo R, Front C, Rear C, LFE 76 CHANNEL_LAYOUT_4_1 = 19, 77 78 // Stereo L, Stereo R, Front C, Side L, Side R, Back C 79 CHANNEL_LAYOUT_6_0 = 20, 80 81 // Stereo L, Stereo R, Side L, Side R, Front LofC, Front RofC 82 CHANNEL_LAYOUT_6_0_FRONT = 21, 83 84 // Stereo L, Stereo R, Front C, Rear L, Rear R, Rear C 85 CHANNEL_LAYOUT_HEXAGONAL = 22, 86 87 // Stereo L, Stereo R, Front C, LFE, Side L, Side R, Rear Center 88 CHANNEL_LAYOUT_6_1 = 23, 89 90 // Stereo L, Stereo R, Front C, LFE, Back L, Back R, Rear Center 91 CHANNEL_LAYOUT_6_1_BACK = 24, 92 93 // Stereo L, Stereo R, Side L, Side R, Front LofC, Front RofC, LFE 94 CHANNEL_LAYOUT_6_1_FRONT = 25, 95 96 // Front L, Front R, Front C, Side L, Side R, Front LofC, Front RofC 97 CHANNEL_LAYOUT_7_0_FRONT = 26, 98 99 // Front L, Front R, Front C, LFE, Back L, Back R, Front LofC, Front RofC 100 CHANNEL_LAYOUT_7_1_WIDE_BACK = 27, 101 102 // Front L, Front R, Front C, Side L, Side R, Rear L, Back R, Back C. 103 CHANNEL_LAYOUT_OCTAGONAL = 28, 104 105 // Channels are not explicitly mapped to speakers. 106 CHANNEL_LAYOUT_DISCRETE = 29, 107 108 // Front L, Front R, Front C. Front C contains the keyboard mic audio. This 109 // layout is only intended for input for WebRTC. The Front C channel 110 // is stripped away in the WebRTC audio input pipeline and never seen outside 111 // of that. 112 CHANNEL_LAYOUT_STEREO_AND_KEYBOARD_MIC = 30, 113 114 // Front L, Front R, Side L, Side R, LFE 115 CHANNEL_LAYOUT_4_1_QUAD_SIDE = 31, 116 117 // Actual channel layout is specified in the bitstream and the actual channel 118 // count is unknown at Chromium media pipeline level (useful for audio 119 // pass-through mode). 120 CHANNEL_LAYOUT_BITSTREAM = 32, 121 122 // Max value, must always equal the largest entry ever logged. 123 CHANNEL_LAYOUT_MAX = CHANNEL_LAYOUT_BITSTREAM 124 }; 125 126 // Note: Do not reorder or reassign these values; other code depends on their 127 // ordering to operate correctly. E.g., CoreAudio channel layout computations. 128 enum Channels { 129 LEFT = 0, 130 RIGHT, 131 CENTER, 132 LFE, 133 BACK_LEFT, 134 BACK_RIGHT, 135 LEFT_OF_CENTER, 136 RIGHT_OF_CENTER, 137 BACK_CENTER, 138 SIDE_LEFT, 139 SIDE_RIGHT, 140 CHANNELS_MAX = 141 SIDE_RIGHT, // Must always equal the largest value ever logged. 142 }; 143 144 // The maximum number of concurrently active channels for all possible layouts. 145 // ChannelLayoutToChannelCount() will never return a value higher than this. 146 constexpr int kMaxConcurrentChannels = 8; 147 148 // Returns the expected channel position in an interleaved stream. Values of -1 149 // mean the channel at that index is not used for that layout. Values range 150 // from 0 to ChannelLayoutToChannelCount(layout) - 1. 151 int ChannelOrder(ChannelLayout layout, Channels channel); 152 153 // Returns the number of channels in a given ChannelLayout. 154 int ChannelLayoutToChannelCount(ChannelLayout layout); 155 156 // Given the number of channels, return the best layout, 157 // or return CHANNEL_LAYOUT_UNSUPPORTED if there is no good match. 158 ChannelLayout GuessChannelLayout(int channels); 159 160 // Returns a string representation of the channel layout. 161 const char* ChannelLayoutToString(ChannelLayout layout); 162 163 } // namespace webrtc 164 165 #endif // API_AUDIO_CHANNEL_LAYOUT_H_