166 lines
5.0 KiB
C++
166 lines
5.0 KiB
C++
/*
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* Copyright (c) 2019 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef API_AUDIO_CHANNEL_LAYOUT_H_
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#define API_AUDIO_CHANNEL_LAYOUT_H_
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namespace webrtc {
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// This file is derived from Chromium's base/channel_layout.h.
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// Enumerates the various representations of the ordering of audio channels.
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// Logged to UMA, so never reuse a value, always add new/greater ones!
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enum ChannelLayout {
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CHANNEL_LAYOUT_NONE = 0,
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CHANNEL_LAYOUT_UNSUPPORTED = 1,
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// Front C
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CHANNEL_LAYOUT_MONO = 2,
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// Front L, Front R
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CHANNEL_LAYOUT_STEREO = 3,
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// Front L, Front R, Back C
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CHANNEL_LAYOUT_2_1 = 4,
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// Front L, Front R, Front C
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CHANNEL_LAYOUT_SURROUND = 5,
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// Front L, Front R, Front C, Back C
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CHANNEL_LAYOUT_4_0 = 6,
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// Front L, Front R, Side L, Side R
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CHANNEL_LAYOUT_2_2 = 7,
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// Front L, Front R, Back L, Back R
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CHANNEL_LAYOUT_QUAD = 8,
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// Front L, Front R, Front C, Side L, Side R
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CHANNEL_LAYOUT_5_0 = 9,
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// Front L, Front R, Front C, LFE, Side L, Side R
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CHANNEL_LAYOUT_5_1 = 10,
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// Front L, Front R, Front C, Back L, Back R
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CHANNEL_LAYOUT_5_0_BACK = 11,
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// Front L, Front R, Front C, LFE, Back L, Back R
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CHANNEL_LAYOUT_5_1_BACK = 12,
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// Front L, Front R, Front C, Side L, Side R, Back L, Back R
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CHANNEL_LAYOUT_7_0 = 13,
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// Front L, Front R, Front C, LFE, Side L, Side R, Back L, Back R
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CHANNEL_LAYOUT_7_1 = 14,
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// Front L, Front R, Front C, LFE, Side L, Side R, Front LofC, Front RofC
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CHANNEL_LAYOUT_7_1_WIDE = 15,
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// Stereo L, Stereo R
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CHANNEL_LAYOUT_STEREO_DOWNMIX = 16,
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// Stereo L, Stereo R, LFE
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CHANNEL_LAYOUT_2POINT1 = 17,
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// Stereo L, Stereo R, Front C, LFE
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CHANNEL_LAYOUT_3_1 = 18,
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// Stereo L, Stereo R, Front C, Rear C, LFE
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CHANNEL_LAYOUT_4_1 = 19,
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// Stereo L, Stereo R, Front C, Side L, Side R, Back C
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CHANNEL_LAYOUT_6_0 = 20,
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// Stereo L, Stereo R, Side L, Side R, Front LofC, Front RofC
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CHANNEL_LAYOUT_6_0_FRONT = 21,
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// Stereo L, Stereo R, Front C, Rear L, Rear R, Rear C
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CHANNEL_LAYOUT_HEXAGONAL = 22,
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// Stereo L, Stereo R, Front C, LFE, Side L, Side R, Rear Center
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CHANNEL_LAYOUT_6_1 = 23,
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// Stereo L, Stereo R, Front C, LFE, Back L, Back R, Rear Center
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CHANNEL_LAYOUT_6_1_BACK = 24,
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// Stereo L, Stereo R, Side L, Side R, Front LofC, Front RofC, LFE
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CHANNEL_LAYOUT_6_1_FRONT = 25,
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// Front L, Front R, Front C, Side L, Side R, Front LofC, Front RofC
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CHANNEL_LAYOUT_7_0_FRONT = 26,
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// Front L, Front R, Front C, LFE, Back L, Back R, Front LofC, Front RofC
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CHANNEL_LAYOUT_7_1_WIDE_BACK = 27,
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// Front L, Front R, Front C, Side L, Side R, Rear L, Back R, Back C.
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CHANNEL_LAYOUT_OCTAGONAL = 28,
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// Channels are not explicitly mapped to speakers.
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CHANNEL_LAYOUT_DISCRETE = 29,
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// Front L, Front R, Front C. Front C contains the keyboard mic audio. This
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// layout is only intended for input for WebRTC. The Front C channel
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// is stripped away in the WebRTC audio input pipeline and never seen outside
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// of that.
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CHANNEL_LAYOUT_STEREO_AND_KEYBOARD_MIC = 30,
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// Front L, Front R, Side L, Side R, LFE
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CHANNEL_LAYOUT_4_1_QUAD_SIDE = 31,
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// Actual channel layout is specified in the bitstream and the actual channel
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// count is unknown at Chromium media pipeline level (useful for audio
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// pass-through mode).
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CHANNEL_LAYOUT_BITSTREAM = 32,
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// Max value, must always equal the largest entry ever logged.
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CHANNEL_LAYOUT_MAX = CHANNEL_LAYOUT_BITSTREAM
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};
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// Note: Do not reorder or reassign these values; other code depends on their
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// ordering to operate correctly. E.g., CoreAudio channel layout computations.
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enum Channels {
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LEFT = 0,
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RIGHT,
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CENTER,
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LFE,
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BACK_LEFT,
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BACK_RIGHT,
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LEFT_OF_CENTER,
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RIGHT_OF_CENTER,
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BACK_CENTER,
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SIDE_LEFT,
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SIDE_RIGHT,
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CHANNELS_MAX =
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SIDE_RIGHT, // Must always equal the largest value ever logged.
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};
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// The maximum number of concurrently active channels for all possible layouts.
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// ChannelLayoutToChannelCount() will never return a value higher than this.
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constexpr int kMaxConcurrentChannels = 8;
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// Returns the expected channel position in an interleaved stream. Values of -1
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// mean the channel at that index is not used for that layout. Values range
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// from 0 to ChannelLayoutToChannelCount(layout) - 1.
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int ChannelOrder(ChannelLayout layout, Channels channel);
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// Returns the number of channels in a given ChannelLayout.
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int ChannelLayoutToChannelCount(ChannelLayout layout);
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// Given the number of channels, return the best layout,
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// or return CHANNEL_LAYOUT_UNSUPPORTED if there is no good match.
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ChannelLayout GuessChannelLayout(int channels);
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// Returns a string representation of the channel layout.
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const char* ChannelLayoutToString(ChannelLayout layout);
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} // namespace webrtc
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#endif // API_AUDIO_CHANNEL_LAYOUT_H_
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