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-rw-r--r--dom/media/webaudio/AnalyserNode.cpp387
1 files changed, 387 insertions, 0 deletions
diff --git a/dom/media/webaudio/AnalyserNode.cpp b/dom/media/webaudio/AnalyserNode.cpp
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+++ b/dom/media/webaudio/AnalyserNode.cpp
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+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/dom/AnalyserNode.h"
+#include "mozilla/dom/AnalyserNodeBinding.h"
+#include "AudioNodeEngine.h"
+#include "AudioNodeStream.h"
+#include "mozilla/Mutex.h"
+#include "mozilla/PodOperations.h"
+
+namespace mozilla {
+
+static const uint32_t MAX_FFT_SIZE = 32768;
+static const size_t CHUNK_COUNT = MAX_FFT_SIZE >> WEBAUDIO_BLOCK_SIZE_BITS;
+static_assert(MAX_FFT_SIZE == CHUNK_COUNT * WEBAUDIO_BLOCK_SIZE,
+ "MAX_FFT_SIZE must be a multiple of WEBAUDIO_BLOCK_SIZE");
+static_assert((CHUNK_COUNT & (CHUNK_COUNT - 1)) == 0,
+ "CHUNK_COUNT must be power of 2 for remainder behavior");
+
+namespace dom {
+
+NS_IMPL_ISUPPORTS_INHERITED0(AnalyserNode, AudioNode)
+
+class AnalyserNodeEngine final : public AudioNodeEngine
+{
+ class TransferBuffer final : public Runnable
+ {
+ public:
+ TransferBuffer(AudioNodeStream* aStream,
+ const AudioChunk& aChunk)
+ : mStream(aStream)
+ , mChunk(aChunk)
+ {
+ }
+
+ NS_IMETHOD Run() override
+ {
+ RefPtr<AnalyserNode> node =
+ static_cast<AnalyserNode*>(mStream->Engine()->NodeMainThread());
+ if (node) {
+ node->AppendChunk(mChunk);
+ }
+ return NS_OK;
+ }
+
+ private:
+ RefPtr<AudioNodeStream> mStream;
+ AudioChunk mChunk;
+ };
+
+public:
+ explicit AnalyserNodeEngine(AnalyserNode* aNode)
+ : AudioNodeEngine(aNode)
+ {
+ MOZ_ASSERT(NS_IsMainThread());
+ }
+
+ virtual void ProcessBlock(AudioNodeStream* aStream,
+ GraphTime aFrom,
+ const AudioBlock& aInput,
+ AudioBlock* aOutput,
+ bool* aFinished) override
+ {
+ *aOutput = aInput;
+
+ if (aInput.IsNull()) {
+ // If AnalyserNode::mChunks has only null chunks, then there is no need
+ // to send further null chunks.
+ if (mChunksToProcess == 0) {
+ return;
+ }
+
+ --mChunksToProcess;
+ if (mChunksToProcess == 0) {
+ aStream->ScheduleCheckForInactive();
+ }
+
+ } else {
+ // This many null chunks will be required to empty AnalyserNode::mChunks.
+ mChunksToProcess = CHUNK_COUNT;
+ }
+
+ RefPtr<TransferBuffer> transfer =
+ new TransferBuffer(aStream, aInput.AsAudioChunk());
+ NS_DispatchToMainThread(transfer);
+ }
+
+ virtual bool IsActive() const override
+ {
+ return mChunksToProcess != 0;
+ }
+
+ virtual size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const override
+ {
+ return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
+ }
+
+ uint32_t mChunksToProcess = 0;
+};
+
+AnalyserNode::AnalyserNode(AudioContext* aContext)
+ : AudioNode(aContext,
+ 1,
+ ChannelCountMode::Max,
+ ChannelInterpretation::Speakers)
+ , mAnalysisBlock(2048)
+ , mMinDecibels(-100.)
+ , mMaxDecibels(-30.)
+ , mSmoothingTimeConstant(.8)
+{
+ mStream = AudioNodeStream::Create(aContext,
+ new AnalyserNodeEngine(this),
+ AudioNodeStream::NO_STREAM_FLAGS,
+ aContext->Graph());
+
+ // Enough chunks must be recorded to handle the case of fftSize being
+ // increased to maximum immediately before getFloatTimeDomainData() is
+ // called, for example.
+ Unused << mChunks.SetLength(CHUNK_COUNT, fallible);
+
+ AllocateBuffer();
+}
+
+size_t
+AnalyserNode::SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const
+{
+ size_t amount = AudioNode::SizeOfExcludingThis(aMallocSizeOf);
+ amount += mAnalysisBlock.SizeOfExcludingThis(aMallocSizeOf);
+ amount += mChunks.ShallowSizeOfExcludingThis(aMallocSizeOf);
+ amount += mOutputBuffer.ShallowSizeOfExcludingThis(aMallocSizeOf);
+ return amount;
+}
+
+size_t
+AnalyserNode::SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const
+{
+ return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
+}
+
+JSObject*
+AnalyserNode::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)
+{
+ return AnalyserNodeBinding::Wrap(aCx, this, aGivenProto);
+}
+
+void
+AnalyserNode::SetFftSize(uint32_t aValue, ErrorResult& aRv)
+{
+ // Disallow values that are not a power of 2 and outside the [32,32768] range
+ if (aValue < 32 ||
+ aValue > MAX_FFT_SIZE ||
+ (aValue & (aValue - 1)) != 0) {
+ aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
+ return;
+ }
+ if (FftSize() != aValue) {
+ mAnalysisBlock.SetFFTSize(aValue);
+ AllocateBuffer();
+ }
+}
+
+void
+AnalyserNode::SetMinDecibels(double aValue, ErrorResult& aRv)
+{
+ if (aValue >= mMaxDecibels) {
+ aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
+ return;
+ }
+ mMinDecibels = aValue;
+}
+
+void
+AnalyserNode::SetMaxDecibels(double aValue, ErrorResult& aRv)
+{
+ if (aValue <= mMinDecibels) {
+ aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
+ return;
+ }
+ mMaxDecibels = aValue;
+}
+
+void
+AnalyserNode::SetSmoothingTimeConstant(double aValue, ErrorResult& aRv)
+{
+ if (aValue < 0 || aValue > 1) {
+ aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
+ return;
+ }
+ mSmoothingTimeConstant = aValue;
+}
+
+void
+AnalyserNode::GetFloatFrequencyData(const Float32Array& aArray)
+{
+ if (!FFTAnalysis()) {
+ // Might fail to allocate memory
+ return;
+ }
+
+ aArray.ComputeLengthAndData();
+
+ float* buffer = aArray.Data();
+ size_t length = std::min(size_t(aArray.Length()), mOutputBuffer.Length());
+
+ for (size_t i = 0; i < length; ++i) {
+ buffer[i] = WebAudioUtils::ConvertLinearToDecibels(mOutputBuffer[i], mMinDecibels);
+ }
+}
+
+void
+AnalyserNode::GetByteFrequencyData(const Uint8Array& aArray)
+{
+ if (!FFTAnalysis()) {
+ // Might fail to allocate memory
+ return;
+ }
+
+ const double rangeScaleFactor = 1.0 / (mMaxDecibels - mMinDecibels);
+
+ aArray.ComputeLengthAndData();
+
+ unsigned char* buffer = aArray.Data();
+ size_t length = std::min(size_t(aArray.Length()), mOutputBuffer.Length());
+
+ for (size_t i = 0; i < length; ++i) {
+ const double decibels = WebAudioUtils::ConvertLinearToDecibels(mOutputBuffer[i], mMinDecibels);
+ // scale down the value to the range of [0, UCHAR_MAX]
+ const double scaled = std::max(0.0, std::min(double(UCHAR_MAX),
+ UCHAR_MAX * (decibels - mMinDecibels) * rangeScaleFactor));
+ buffer[i] = static_cast<unsigned char>(scaled);
+ }
+}
+
+void
+AnalyserNode::GetFloatTimeDomainData(const Float32Array& aArray)
+{
+ aArray.ComputeLengthAndData();
+
+ float* buffer = aArray.Data();
+ size_t length = std::min(aArray.Length(), FftSize());
+
+ GetTimeDomainData(buffer, length);
+}
+
+void
+AnalyserNode::GetByteTimeDomainData(const Uint8Array& aArray)
+{
+ aArray.ComputeLengthAndData();
+
+ size_t length = std::min(aArray.Length(), FftSize());
+
+ AlignedTArray<float> tmpBuffer;
+ if (!tmpBuffer.SetLength(length, fallible)) {
+ return;
+ }
+
+ GetTimeDomainData(tmpBuffer.Elements(), length);
+
+ unsigned char* buffer = aArray.Data();
+ for (size_t i = 0; i < length; ++i) {
+ const float value = tmpBuffer[i];
+ // scale the value to the range of [0, UCHAR_MAX]
+ const float scaled = std::max(0.0f, std::min(float(UCHAR_MAX),
+ 128.0f * (value + 1.0f)));
+ buffer[i] = static_cast<unsigned char>(scaled);
+ }
+}
+
+bool
+AnalyserNode::FFTAnalysis()
+{
+ AlignedTArray<float> tmpBuffer;
+ size_t fftSize = FftSize();
+ if (!tmpBuffer.SetLength(fftSize, fallible)) {
+ return false;
+ }
+
+ float* inputBuffer = tmpBuffer.Elements();
+ GetTimeDomainData(inputBuffer, fftSize);
+ ApplyBlackmanWindow(inputBuffer, fftSize);
+ mAnalysisBlock.PerformFFT(inputBuffer);
+
+ // Normalize so than an input sine wave at 0dBfs registers as 0dBfs (undo FFT scaling factor).
+ const double magnitudeScale = 1.0 / fftSize;
+
+ for (uint32_t i = 0; i < mOutputBuffer.Length(); ++i) {
+ double scalarMagnitude = NS_hypot(mAnalysisBlock.RealData(i),
+ mAnalysisBlock.ImagData(i)) *
+ magnitudeScale;
+ mOutputBuffer[i] = mSmoothingTimeConstant * mOutputBuffer[i] +
+ (1.0 - mSmoothingTimeConstant) * scalarMagnitude;
+ }
+
+ return true;
+}
+
+void
+AnalyserNode::ApplyBlackmanWindow(float* aBuffer, uint32_t aSize)
+{
+ double alpha = 0.16;
+ double a0 = 0.5 * (1.0 - alpha);
+ double a1 = 0.5;
+ double a2 = 0.5 * alpha;
+
+ for (uint32_t i = 0; i < aSize; ++i) {
+ double x = double(i) / aSize;
+ double window = a0 - a1 * cos(2 * M_PI * x) + a2 * cos(4 * M_PI * x);
+ aBuffer[i] *= window;
+ }
+}
+
+bool
+AnalyserNode::AllocateBuffer()
+{
+ bool result = true;
+ if (mOutputBuffer.Length() != FrequencyBinCount()) {
+ if (!mOutputBuffer.SetLength(FrequencyBinCount(), fallible)) {
+ return false;
+ }
+ memset(mOutputBuffer.Elements(), 0, sizeof(float) * FrequencyBinCount());
+ }
+ return result;
+}
+
+void
+AnalyserNode::AppendChunk(const AudioChunk& aChunk)
+{
+ if (mChunks.Length() == 0) {
+ return;
+ }
+
+ ++mCurrentChunk;
+ mChunks[mCurrentChunk & (CHUNK_COUNT - 1)] = aChunk;
+}
+
+// Reads into aData the oldest aLength samples of the fftSize most recent
+// samples.
+void
+AnalyserNode::GetTimeDomainData(float* aData, size_t aLength)
+{
+ size_t fftSize = FftSize();
+ MOZ_ASSERT(aLength <= fftSize);
+
+ if (mChunks.Length() == 0) {
+ PodZero(aData, aLength);
+ return;
+ }
+
+ size_t readChunk =
+ mCurrentChunk - ((fftSize - 1) >> WEBAUDIO_BLOCK_SIZE_BITS);
+ size_t readIndex = (0 - fftSize) & (WEBAUDIO_BLOCK_SIZE - 1);
+ MOZ_ASSERT(readIndex == 0 || readIndex + fftSize == WEBAUDIO_BLOCK_SIZE);
+
+ for (size_t writeIndex = 0; writeIndex < aLength; ) {
+ const AudioChunk& chunk = mChunks[readChunk & (CHUNK_COUNT - 1)];
+ const size_t channelCount = chunk.ChannelCount();
+ size_t copyLength =
+ std::min<size_t>(aLength - writeIndex, WEBAUDIO_BLOCK_SIZE);
+ float* dataOut = &aData[writeIndex];
+
+ if (channelCount == 0) {
+ PodZero(dataOut, copyLength);
+ } else {
+ float scale = chunk.mVolume / channelCount;
+ { // channel 0
+ auto channelData =
+ static_cast<const float*>(chunk.mChannelData[0]) + readIndex;
+ AudioBufferCopyWithScale(channelData, scale, dataOut, copyLength);
+ }
+ for (uint32_t i = 1; i < channelCount; ++i) {
+ auto channelData =
+ static_cast<const float*>(chunk.mChannelData[i]) + readIndex;
+ AudioBufferAddWithScale(channelData, scale, dataOut, copyLength);
+ }
+ }
+
+ readChunk++;
+ writeIndex += copyLength;
+ }
+}
+
+} // namespace dom
+} // namespace mozilla
+