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comparison: content/media/AudioChannelFormat.h
content/media/AudioChannelFormat.h
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- TOR_BUG_9701
- changeset 11
- deefc01c0e14
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| 1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ | |
| 2 /* vim:set ts=2 sw=2 sts=2 et cindent: */ | |
| 3 /* This Source Code Form is subject to the terms of the Mozilla Public | |
| 4 * License, v. 2.0. If a copy of the MPL was not distributed with this | |
| 5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ | |
| 6 #ifndef MOZILLA_AUDIOCHANNELFORMAT_H_ | |
| 7 #define MOZILLA_AUDIOCHANNELFORMAT_H_ | |
| 8 | |
| 9 #include <stdint.h> | |
| 10 | |
| 11 #include "nsTArrayForwardDeclare.h" | |
| 12 | |
| 13 namespace mozilla { | |
| 14 | |
| 15 /* | |
| 16 * This file provides utilities for upmixing and downmixing channels. | |
| 17 * | |
| 18 * The channel layouts, upmixing and downmixing are consistent with the | |
| 19 * Web Audio spec. | |
| 20 * | |
| 21 * Channel layouts for up to 6 channels: | |
| 22 * mono { M } | |
| 23 * stereo { L, R } | |
| 24 * { L, R, C } | |
| 25 * quad { L, R, SL, SR } | |
| 26 * { L, R, C, SL, SR } | |
| 27 * 5.1 { L, R, C, LFE, SL, SR } | |
| 28 * | |
| 29 * Only 1, 2, 4 and 6 are currently defined in Web Audio. | |
| 30 */ | |
| 31 | |
| 32 /** | |
| 33 * Return a channel count whose channel layout includes all the channels from | |
| 34 * aChannels1 and aChannels2. | |
| 35 */ | |
| 36 uint32_t | |
| 37 GetAudioChannelsSuperset(uint32_t aChannels1, uint32_t aChannels2); | |
| 38 | |
| 39 /** | |
| 40 * Given an array of input channel data, and an output channel count, | |
| 41 * replaces the array with an array of upmixed channels. | |
| 42 * This shuffles the array and may set some channel buffers to aZeroChannel. | |
| 43 * Don't call this with input count >= output count. | |
| 44 * This may return *more* channels than requested. In that case, downmixing | |
| 45 * is required to to get to aOutputChannelCount. (This is how we handle | |
| 46 * odd cases like 3 -> 4 upmixing.) | |
| 47 * If aChannelArray.Length() was the input to one of a series of | |
| 48 * GetAudioChannelsSuperset calls resulting in aOutputChannelCount, | |
| 49 * no downmixing will be required. | |
| 50 */ | |
| 51 void | |
| 52 AudioChannelsUpMix(nsTArray<const void*>* aChannelArray, | |
| 53 uint32_t aOutputChannelCount, | |
| 54 const void* aZeroChannel); | |
| 55 | |
| 56 /** | |
| 57 * Given an array of input channels (which must be float format!), | |
| 58 * downmix to aOutputChannelCount, and copy the results to the | |
| 59 * channel buffers in aOutputChannels. | |
| 60 * Don't call this with input count <= output count. | |
| 61 */ | |
| 62 void | |
| 63 AudioChannelsDownMix(const nsTArray<const void*>& aChannelArray, | |
| 64 float** aOutputChannels, | |
| 65 uint32_t aOutputChannelCount, | |
| 66 uint32_t aDuration); | |
| 67 | |
| 68 // A version of AudioChannelsDownMix that downmixes int16_ts may be required. | |
| 69 | |
| 70 } // namespace mozilla | |
| 71 | |
| 72 #endif /* MOZILLA_AUDIOCHANNELFORMAT_H_ */ |
