gecko/content/media/webaudio/blink/ReverbConvolver.cpp

238 lines
10 KiB
C++

/*
* Copyright (C) 2010 Google Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "ReverbConvolver.h"
#include "ReverbConvolverStage.h"
using namespace mozilla;
template<>
struct RunnableMethodTraits<WebCore::ReverbConvolver>
{
static void RetainCallee(WebCore::ReverbConvolver* obj) {}
static void ReleaseCallee(WebCore::ReverbConvolver* obj) {}
};
namespace WebCore {
const int InputBufferSize = 8 * 16384;
// We only process the leading portion of the impulse response in the real-time thread. We don't exceed this length.
// It turns out then, that the background thread has about 278msec of scheduling slop.
// Empirically, this has been found to be a good compromise between giving enough time for scheduling slop,
// while still minimizing the amount of processing done in the primary (high-priority) thread.
// This was found to be a good value on Mac OS X, and may work well on other platforms as well, assuming
// the very rough scheduling latencies are similar on these time-scales. Of course, this code may need to be
// tuned for individual platforms if this assumption is found to be incorrect.
const size_t RealtimeFrameLimit = 8192 + 4096; // ~278msec @ 44.1KHz
const size_t MinFFTSize = 128;
const size_t MaxRealtimeFFTSize = 2048;
ReverbConvolver::ReverbConvolver(const float* impulseResponseData, size_t impulseResponseLength, size_t renderSliceSize, size_t maxFFTSize, size_t convolverRenderPhase, bool useBackgroundThreads)
: m_impulseResponseLength(impulseResponseLength)
, m_accumulationBuffer(impulseResponseLength + renderSliceSize)
, m_inputBuffer(InputBufferSize)
, m_minFFTSize(MinFFTSize) // First stage will have this size - successive stages will double in size each time
, m_maxFFTSize(maxFFTSize) // until we hit m_maxFFTSize
, m_backgroundThread("ConvolverWorker")
, m_backgroundThreadCondition(&m_backgroundThreadLock)
, m_useBackgroundThreads(useBackgroundThreads)
, m_wantsToExit(false)
, m_moreInputBuffered(false)
{
// If we are using background threads then don't exceed this FFT size for the
// stages which run in the real-time thread. This avoids having only one or two
// large stages (size 16384 or so) at the end which take a lot of time every several
// processing slices. This way we amortize the cost over more processing slices.
m_maxRealtimeFFTSize = MaxRealtimeFFTSize;
// For the moment, a good way to know if we have real-time constraint is to check if we're using background threads.
// Otherwise, assume we're being run from a command-line tool.
bool hasRealtimeConstraint = useBackgroundThreads;
const float* response = impulseResponseData;
size_t totalResponseLength = impulseResponseLength;
// The total latency is zero because the direct-convolution is used in the leading portion.
size_t reverbTotalLatency = 0;
size_t stageOffset = 0;
int i = 0;
size_t fftSize = m_minFFTSize;
while (stageOffset < totalResponseLength) {
size_t stageSize = fftSize / 2;
// For the last stage, it's possible that stageOffset is such that we're straddling the end
// of the impulse response buffer (if we use stageSize), so reduce the last stage's length...
if (stageSize + stageOffset > totalResponseLength)
stageSize = totalResponseLength - stageOffset;
// This "staggers" the time when each FFT happens so they don't all happen at the same time
int renderPhase = convolverRenderPhase + i * renderSliceSize;
bool useDirectConvolver = !stageOffset;
nsAutoPtr<ReverbConvolverStage> stage(new ReverbConvolverStage(response, totalResponseLength, reverbTotalLatency, stageOffset, stageSize, fftSize, renderPhase, renderSliceSize, &m_accumulationBuffer, useDirectConvolver));
bool isBackgroundStage = false;
if (this->useBackgroundThreads() && stageOffset > RealtimeFrameLimit) {
m_backgroundStages.AppendElement(stage.forget());
isBackgroundStage = true;
} else
m_stages.AppendElement(stage.forget());
stageOffset += stageSize;
++i;
if (!useDirectConvolver) {
// Figure out next FFT size
fftSize *= 2;
}
if (hasRealtimeConstraint && !isBackgroundStage && fftSize > m_maxRealtimeFFTSize)
fftSize = m_maxRealtimeFFTSize;
if (fftSize > m_maxFFTSize)
fftSize = m_maxFFTSize;
}
// Start up background thread
// FIXME: would be better to up the thread priority here. It doesn't need to be real-time, but higher than the default...
if (this->useBackgroundThreads() && m_backgroundStages.Length() > 0) {
m_backgroundThread.Start();
CancelableTask* task = NewRunnableMethod(this, &ReverbConvolver::backgroundThreadEntry);
m_backgroundThread.message_loop()->PostTask(FROM_HERE, task);
}
}
ReverbConvolver::~ReverbConvolver()
{
// Wait for background thread to stop
if (useBackgroundThreads() && m_backgroundThread.IsRunning()) {
m_wantsToExit = true;
// Wake up thread so it can return
{
AutoLock locker(m_backgroundThreadLock);
m_moreInputBuffered = true;
m_backgroundThreadCondition.Signal();
}
m_backgroundThread.Stop();
}
}
void ReverbConvolver::backgroundThreadEntry()
{
while (!m_wantsToExit) {
// Wait for realtime thread to give us more input
m_moreInputBuffered = false;
{
AutoLock locker(m_backgroundThreadLock);
while (!m_moreInputBuffered && !m_wantsToExit)
m_backgroundThreadCondition.Wait();
}
// Process all of the stages until their read indices reach the input buffer's write index
int writeIndex = m_inputBuffer.writeIndex();
// Even though it doesn't seem like every stage needs to maintain its own version of readIndex
// we do this in case we want to run in more than one background thread.
int readIndex;
while ((readIndex = m_backgroundStages[0]->inputReadIndex()) != writeIndex) { // FIXME: do better to detect buffer overrun...
// The ReverbConvolverStages need to process in amounts which evenly divide half the FFT size
const int SliceSize = MinFFTSize / 2;
// Accumulate contributions from each stage
for (size_t i = 0; i < m_backgroundStages.Length(); ++i)
m_backgroundStages[i]->processInBackground(this, SliceSize);
}
}
}
void ReverbConvolver::process(const float* sourceChannelData, size_t sourceChannelLength,
float* destinationChannelData, size_t destinationChannelLength,
size_t framesToProcess)
{
bool isSafe = sourceChannelData && destinationChannelData && sourceChannelLength >= framesToProcess && destinationChannelLength >= framesToProcess;
MOZ_ASSERT(isSafe);
if (!isSafe)
return;
const float* source = sourceChannelData;
float* destination = destinationChannelData;
bool isDataSafe = source && destination;
MOZ_ASSERT(isDataSafe);
if (!isDataSafe)
return;
// Feed input buffer (read by all threads)
m_inputBuffer.write(source, framesToProcess);
// Accumulate contributions from each stage
for (size_t i = 0; i < m_stages.Length(); ++i)
m_stages[i]->process(source, framesToProcess);
// Finally read from accumulation buffer
m_accumulationBuffer.readAndClear(destination, framesToProcess);
// Now that we've buffered more input, wake up our background thread.
// Not using a MutexLocker looks strange, but we use a tryLock() instead because this is run on the real-time
// thread where it is a disaster for the lock to be contended (causes audio glitching). It's OK if we fail to
// signal from time to time, since we'll get to it the next time we're called. We're called repeatedly
// and frequently (around every 3ms). The background thread is processing well into the future and has a considerable amount of
// leeway here...
if (m_backgroundThreadLock.Try()) {
m_moreInputBuffered = true;
m_backgroundThreadCondition.Signal();
m_backgroundThreadLock.Release();
}
}
void ReverbConvolver::reset()
{
for (size_t i = 0; i < m_stages.Length(); ++i)
m_stages[i]->reset();
for (size_t i = 0; i < m_backgroundStages.Length(); ++i)
m_backgroundStages[i]->reset();
m_accumulationBuffer.reset();
m_inputBuffer.reset();
}
size_t ReverbConvolver::latencyFrames() const
{
return 0;
}
} // namespace WebCore