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f781f8cc60
X-Git-Commit-ID: e3c9ccaf984c74bb041e2a35fb092dd91e643555 X-Mailer: git-send-email --HG-- extra : rebase_source : c26ad3b5953f15b599baa9fea0cf66580f2a3262
86 lines
2.7 KiB
C++
86 lines
2.7 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim:set ts=2 sw=2 sts=2 et cindent: */
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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
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef GainProcessor_h_
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#define GainProcessor_h_
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#include "AudioNodeStream.h"
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#include "AudioDestinationNode.h"
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#include "WebAudioUtils.h"
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namespace mozilla {
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namespace dom {
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// This class implements the gain processing logic used by GainNodeEngine
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// and AudioBufferSourceNodeEngine.
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class GainProcessor
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{
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public:
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explicit GainProcessor(AudioDestinationNode* aDestination)
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: mSource(nullptr)
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, mDestination(static_cast<AudioNodeStream*> (aDestination->Stream()))
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, mGain(1.f)
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{
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}
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void SetSourceStream(AudioNodeStream* aSource)
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{
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mSource = aSource;
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}
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void SetGainParameter(const AudioParamTimeline& aValue)
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{
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MOZ_ASSERT(mSource && mDestination);
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mGain = aValue;
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WebAudioUtils::ConvertAudioParamToTicks(mGain, mSource, mDestination);
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}
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void ProcessGain(AudioNodeStream* aStream,
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float aInputVolume,
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const nsTArray<const void*>& aInputChannelData,
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AudioChunk* aOutput)
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{
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MOZ_ASSERT(mSource == aStream, "Invalid source stream");
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if (mGain.HasSimpleValue()) {
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// Optimize the case where we only have a single value set as the volume
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aOutput->mVolume *= mGain.GetValue();
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} else {
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// First, compute a vector of gains for each track tick based on the
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// timeline at hand, and then for each channel, multiply the values
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// in the buffer with the gain vector.
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// Compute the gain values for the duration of the input AudioChunk
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// XXX we need to add a method to AudioEventTimeline to compute this buffer directly.
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float computedGain[WEBAUDIO_BLOCK_SIZE];
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for (size_t counter = 0; counter < WEBAUDIO_BLOCK_SIZE; ++counter) {
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TrackTicks tick = aStream->GetCurrentPosition();
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computedGain[counter] = mGain.GetValueAtTime(tick, counter) * aInputVolume;
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}
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// Apply the gain to the output buffer
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MOZ_ASSERT(aInputChannelData.Length() == aOutput->mChannelData.Length());
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for (size_t channel = 0; channel < aOutput->mChannelData.Length(); ++channel) {
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const float* inputBuffer = static_cast<const float*> (aInputChannelData[channel]);
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float* buffer = static_cast<float*> (const_cast<void*>
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(aOutput->mChannelData[channel]));
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AudioBlockCopyChannelWithScale(inputBuffer, computedGain, buffer);
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}
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}
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}
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protected:
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AudioNodeStream* mSource;
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AudioNodeStream* mDestination;
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AudioParamTimeline mGain;
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};
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}
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}
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#endif
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