content/media/AudioChannelFormat.h@44a2da4a2ab2 (annotated)
content/media/AudioChannelFormat.h
Fri, 16 Jan 2015 04:50:19 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Fri, 16 Jan 2015 04:50:19 +0100
- branch
- TOR_BUG_9701
- changeset 13
- 44a2da4a2ab2
- permissions
- -rw-r--r--
Replace accessor implementation with direct member state manipulation, by
request https://trac.torproject.org/projects/tor/ticket/9701#comment:32
| michael@0 | 1 | /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ |
| michael@0 | 2 | /* vim:set ts=2 sw=2 sts=2 et cindent: */ |
| michael@0 | 3 | /* This Source Code Form is subject to the terms of the Mozilla Public |
| michael@0 | 4 | * License, v. 2.0. If a copy of the MPL was not distributed with this |
| michael@0 | 5 | * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| michael@0 | 6 | #ifndef MOZILLA_AUDIOCHANNELFORMAT_H_ |
| michael@0 | 7 | #define MOZILLA_AUDIOCHANNELFORMAT_H_ |
| michael@0 | 8 | |
| michael@0 | 9 | #include <stdint.h> |
| michael@0 | 10 | |
| michael@0 | 11 | #include "nsTArrayForwardDeclare.h" |
| michael@0 | 12 | |
| michael@0 | 13 | namespace mozilla { |
| michael@0 | 14 | |
| michael@0 | 15 | /* |
| michael@0 | 16 | * This file provides utilities for upmixing and downmixing channels. |
| michael@0 | 17 | * |
| michael@0 | 18 | * The channel layouts, upmixing and downmixing are consistent with the |
| michael@0 | 19 | * Web Audio spec. |
| michael@0 | 20 | * |
| michael@0 | 21 | * Channel layouts for up to 6 channels: |
| michael@0 | 22 | * mono { M } |
| michael@0 | 23 | * stereo { L, R } |
| michael@0 | 24 | * { L, R, C } |
| michael@0 | 25 | * quad { L, R, SL, SR } |
| michael@0 | 26 | * { L, R, C, SL, SR } |
| michael@0 | 27 | * 5.1 { L, R, C, LFE, SL, SR } |
| michael@0 | 28 | * |
| michael@0 | 29 | * Only 1, 2, 4 and 6 are currently defined in Web Audio. |
| michael@0 | 30 | */ |
| michael@0 | 31 | |
| michael@0 | 32 | /** |
| michael@0 | 33 | * Return a channel count whose channel layout includes all the channels from |
| michael@0 | 34 | * aChannels1 and aChannels2. |
| michael@0 | 35 | */ |
| michael@0 | 36 | uint32_t |
| michael@0 | 37 | GetAudioChannelsSuperset(uint32_t aChannels1, uint32_t aChannels2); |
| michael@0 | 38 | |
| michael@0 | 39 | /** |
| michael@0 | 40 | * Given an array of input channel data, and an output channel count, |
| michael@0 | 41 | * replaces the array with an array of upmixed channels. |
| michael@0 | 42 | * This shuffles the array and may set some channel buffers to aZeroChannel. |
| michael@0 | 43 | * Don't call this with input count >= output count. |
| michael@0 | 44 | * This may return *more* channels than requested. In that case, downmixing |
| michael@0 | 45 | * is required to to get to aOutputChannelCount. (This is how we handle |
| michael@0 | 46 | * odd cases like 3 -> 4 upmixing.) |
| michael@0 | 47 | * If aChannelArray.Length() was the input to one of a series of |
| michael@0 | 48 | * GetAudioChannelsSuperset calls resulting in aOutputChannelCount, |
| michael@0 | 49 | * no downmixing will be required. |
| michael@0 | 50 | */ |
| michael@0 | 51 | void |
| michael@0 | 52 | AudioChannelsUpMix(nsTArray<const void*>* aChannelArray, |
| michael@0 | 53 | uint32_t aOutputChannelCount, |
| michael@0 | 54 | const void* aZeroChannel); |
| michael@0 | 55 | |
| michael@0 | 56 | /** |
| michael@0 | 57 | * Given an array of input channels (which must be float format!), |
| michael@0 | 58 | * downmix to aOutputChannelCount, and copy the results to the |
| michael@0 | 59 | * channel buffers in aOutputChannels. |
| michael@0 | 60 | * Don't call this with input count <= output count. |
| michael@0 | 61 | */ |
| michael@0 | 62 | void |
| michael@0 | 63 | AudioChannelsDownMix(const nsTArray<const void*>& aChannelArray, |
| michael@0 | 64 | float** aOutputChannels, |
| michael@0 | 65 | uint32_t aOutputChannelCount, |
| michael@0 | 66 | uint32_t aDuration); |
| michael@0 | 67 | |
| michael@0 | 68 | // A version of AudioChannelsDownMix that downmixes int16_ts may be required. |
| michael@0 | 69 | |
| michael@0 | 70 | } // namespace mozilla |
| michael@0 | 71 | |
| michael@0 | 72 | #endif /* MOZILLA_AUDIOCHANNELFORMAT_H_ */ |
