| // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef MEDIA_BASE_CHANNEL_LAYOUT_H_ |
| #define MEDIA_BASE_CHANNEL_LAYOUT_H_ |
| |
| #include "media/base/media_shmem_export.h" |
| |
| namespace media { |
| |
| // Enumerates the various representations of the ordering of audio channels. |
| // Logged to UMA, so never reuse a value, always add new/greater ones! |
| enum ChannelLayout { |
| CHANNEL_LAYOUT_NONE = 0, |
| CHANNEL_LAYOUT_UNSUPPORTED = 1, |
| |
| // Front C |
| CHANNEL_LAYOUT_MONO = 2, |
| |
| // Front L, Front R |
| CHANNEL_LAYOUT_STEREO = 3, |
| |
| // Front L, Front R, Back C |
| CHANNEL_LAYOUT_2_1 = 4, |
| |
| // Front L, Front R, Front C |
| CHANNEL_LAYOUT_SURROUND = 5, |
| |
| // Front L, Front R, Front C, Back C |
| CHANNEL_LAYOUT_4_0 = 6, |
| |
| // Front L, Front R, Side L, Side R |
| CHANNEL_LAYOUT_2_2 = 7, |
| |
| // Front L, Front R, Back L, Back R |
| CHANNEL_LAYOUT_QUAD = 8, |
| |
| // Front L, Front R, Front C, Side L, Side R |
| CHANNEL_LAYOUT_5_0 = 9, |
| |
| // Front L, Front R, Front C, LFE, Side L, Side R |
| CHANNEL_LAYOUT_5_1 = 10, |
| |
| // Front L, Front R, Front C, Back L, Back R |
| CHANNEL_LAYOUT_5_0_BACK = 11, |
| |
| // Front L, Front R, Front C, LFE, Back L, Back R |
| CHANNEL_LAYOUT_5_1_BACK = 12, |
| |
| // Front L, Front R, Front C, Side L, Side R, Back L, Back R |
| CHANNEL_LAYOUT_7_0 = 13, |
| |
| // Front L, Front R, Front C, LFE, Side L, Side R, Back L, Back R |
| CHANNEL_LAYOUT_7_1 = 14, |
| |
| // Front L, Front R, Front C, LFE, Side L, Side R, Front LofC, Front RofC |
| CHANNEL_LAYOUT_7_1_WIDE = 15, |
| |
| // Stereo L, Stereo R |
| CHANNEL_LAYOUT_STEREO_DOWNMIX = 16, |
| |
| // Stereo L, Stereo R, LFE |
| CHANNEL_LAYOUT_2POINT1 = 17, |
| |
| // Stereo L, Stereo R, Front C, LFE |
| CHANNEL_LAYOUT_3_1 = 18, |
| |
| // Stereo L, Stereo R, Front C, Rear C, LFE |
| CHANNEL_LAYOUT_4_1 = 19, |
| |
| // Stereo L, Stereo R, Front C, Side L, Side R, Back C |
| CHANNEL_LAYOUT_6_0 = 20, |
| |
| // Stereo L, Stereo R, Side L, Side R, Front LofC, Front RofC |
| CHANNEL_LAYOUT_6_0_FRONT = 21, |
| |
| // Stereo L, Stereo R, Front C, Rear L, Rear R, Rear C |
| CHANNEL_LAYOUT_HEXAGONAL = 22, |
| |
| // Stereo L, Stereo R, Front C, LFE, Side L, Side R, Rear Center |
| CHANNEL_LAYOUT_6_1 = 23, |
| |
| // Stereo L, Stereo R, Front C, LFE, Back L, Back R, Rear Center |
| CHANNEL_LAYOUT_6_1_BACK = 24, |
| |
| // Stereo L, Stereo R, Side L, Side R, Front LofC, Front RofC, LFE |
| CHANNEL_LAYOUT_6_1_FRONT = 25, |
| |
| // Front L, Front R, Front C, Side L, Side R, Front LofC, Front RofC |
| CHANNEL_LAYOUT_7_0_FRONT = 26, |
| |
| // Front L, Front R, Front C, LFE, Back L, Back R, Front LofC, Front RofC |
| CHANNEL_LAYOUT_7_1_WIDE_BACK = 27, |
| |
| // Front L, Front R, Front C, Side L, Side R, Rear L, Back R, Back C. |
| CHANNEL_LAYOUT_OCTAGONAL = 28, |
| |
| // Channels are not explicitly mapped to speakers. |
| CHANNEL_LAYOUT_DISCRETE = 29, |
| |
| // Front L, Front R, Front C. Front C contains the keyboard mic audio. This |
| // layout is only intended for input for WebRTC. The Front C channel |
| // is stripped away in the WebRTC audio input pipeline and never seen outside |
| // of that. |
| CHANNEL_LAYOUT_STEREO_AND_KEYBOARD_MIC = 30, |
| |
| // Front L, Front R, Side L, Side R, LFE |
| CHANNEL_LAYOUT_4_1_QUAD_SIDE = 31, |
| |
| // Actual channel layout is specified in the bitstream and the actual channel |
| // count is unknown at Chromium media pipeline level (useful for audio |
| // pass-through mode). |
| CHANNEL_LAYOUT_BITSTREAM = 32, |
| |
| // Max value, must always equal the largest entry ever logged. |
| CHANNEL_LAYOUT_MAX = CHANNEL_LAYOUT_BITSTREAM |
| }; |
| |
| // Note: Do not reorder or reassign these values; other code depends on their |
| // ordering to operate correctly. E.g., CoreAudio channel layout computations. |
| enum Channels { |
| LEFT = 0, |
| RIGHT, |
| CENTER, |
| LFE, |
| BACK_LEFT, |
| BACK_RIGHT, |
| LEFT_OF_CENTER, |
| RIGHT_OF_CENTER, |
| BACK_CENTER, |
| SIDE_LEFT, |
| SIDE_RIGHT, |
| CHANNELS_MAX = SIDE_RIGHT, // Must always equal the largest value ever logged. |
| }; |
| |
| // The maximum number of concurrently active channels for all possible layouts. |
| // ChannelLayoutToChannelCount() will never return a value higher than this. |
| constexpr int kMaxConcurrentChannels = 8; |
| |
| // Returns the expected channel position in an interleaved stream. Values of -1 |
| // mean the channel at that index is not used for that layout. Values range |
| // from 0 to ChannelLayoutToChannelCount(layout) - 1. |
| MEDIA_SHMEM_EXPORT int ChannelOrder(ChannelLayout layout, Channels channel); |
| |
| // Returns the number of channels in a given ChannelLayout. |
| MEDIA_SHMEM_EXPORT int ChannelLayoutToChannelCount(ChannelLayout layout); |
| |
| // Given the number of channels, return the best layout, |
| // or return CHANNEL_LAYOUT_UNSUPPORTED if there is no good match. |
| MEDIA_SHMEM_EXPORT ChannelLayout GuessChannelLayout(int channels); |
| |
| // Returns a string representation of the channel layout. |
| MEDIA_SHMEM_EXPORT const char* ChannelLayoutToString(ChannelLayout layout); |
| |
| } // namespace media |
| |
| #endif // MEDIA_BASE_CHANNEL_LAYOUT_H_ |