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aa81ed9e24
Use the sample rate passed to the OfflineAudioContext constructor in MediaStreamGraph::CreateOfflineInstance, and pass the preferred mixer sample rate to the (real time) MediaStreamGraph constructor. Then, always use this sample rate for the lifetime of the graph. This patch needed to pass the sample rate to the AudioMixer class to avoid relying on globals like it was done before. --HG-- extra : rebase_source : 2802208819887605fe26a7040998fc328b3c9a57
96 lines
2.9 KiB
C++
96 lines
2.9 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this file,
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* You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef MOZILLA_AUDIOMIXER_H_
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#define MOZILLA_AUDIOMIXER_H_
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#include "AudioSampleFormat.h"
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#include "nsTArray.h"
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#include "mozilla/PodOperations.h"
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namespace mozilla {
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typedef void(*MixerFunc)(AudioDataValue* aMixedBuffer,
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AudioSampleFormat aFormat,
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uint32_t aChannels,
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uint32_t aFrames,
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uint32_t aSampleRate);
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/**
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* This class mixes multiple streams of audio together to output a single audio
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* stream.
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*
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* AudioMixer::Mix is to be called repeatedly with buffers that have the same
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* length, sample rate, sample format and channel count.
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*
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* When all the tracks have been mixed, calling FinishMixing will call back with
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* a buffer containing the mixed audio data.
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*
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* This class is not thread safe.
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*/
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class AudioMixer
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{
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public:
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AudioMixer(MixerFunc aCallback)
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: mCallback(aCallback),
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mFrames(0),
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mChannels(0),
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mSampleRate(0)
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{ }
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/* Get the data from the mixer. This is supposed to be called when all the
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* tracks have been mixed in. The caller should not hold onto the data. */
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void FinishMixing() {
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mCallback(mMixedAudio.Elements(),
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AudioSampleTypeToFormat<AudioDataValue>::Format,
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mChannels,
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mFrames,
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mSampleRate);
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PodZero(mMixedAudio.Elements(), mMixedAudio.Length());
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mSampleRate = mChannels = mFrames = 0;
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}
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/* Add a buffer to the mix. aSamples is interleaved. */
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void Mix(AudioDataValue* aSamples,
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uint32_t aChannels,
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uint32_t aFrames,
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uint32_t aSampleRate) {
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if (!mFrames && !mChannels) {
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mFrames = aFrames;
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mChannels = aChannels;
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mSampleRate = aSampleRate;
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EnsureCapacityAndSilence();
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}
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MOZ_ASSERT(aFrames == mFrames);
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MOZ_ASSERT(aChannels == mChannels);
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MOZ_ASSERT(aSampleRate == mSampleRate);
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for (uint32_t i = 0; i < aFrames * aChannels; i++) {
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mMixedAudio[i] += aSamples[i];
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}
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}
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private:
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void EnsureCapacityAndSilence() {
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if (mFrames * mChannels > mMixedAudio.Length()) {
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mMixedAudio.SetLength(mFrames* mChannels);
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}
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PodZero(mMixedAudio.Elements(), mMixedAudio.Length());
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}
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/* Function that is called when the mixing is done. */
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MixerFunc mCallback;
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/* Number of frames for this mixing block. */
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uint32_t mFrames;
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/* Number of channels for this mixing block. */
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uint32_t mChannels;
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/* Sample rate the of the mixed data. */
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uint32_t mSampleRate;
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/* Buffer containing the mixed audio data. */
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nsTArray<AudioDataValue> mMixedAudio;
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};
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}
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#endif // MOZILLA_AUDIOMIXER_H_
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