The Tor Browser: content/media/webaudio/blink/ReverbConvolver.cpp@b8a032363ba2 (annotated)

content/media/webaudio/blink/ReverbConvolver.cpp@b8a032363ba2 (annotated)

content/media/webaudio/blink/ReverbConvolver.cpp

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /*
  * 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
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * 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) {
         if (!m_backgroundThread.Start()) {
           NS_WARNING("Cannot start convolver thread.");
           return;
         }
         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();
     }
 }
 size_t ReverbConvolver::sizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
 {
     size_t amount = aMallocSizeOf(this);
     amount += m_stages.SizeOfExcludingThis(aMallocSizeOf);
     for (size_t i = 0; i < m_stages.Length(); i++) {
         if (m_stages[i]) {
             amount += m_stages[i]->sizeOfIncludingThis(aMallocSizeOf);
         }
     }
     amount += m_backgroundStages.SizeOfExcludingThis(aMallocSizeOf);
     for (size_t i = 0; i < m_backgroundStages.Length(); i++) {
         if (m_backgroundStages[i]) {
             amount += m_backgroundStages[i]->sizeOfIncludingThis(aMallocSizeOf);
         }
     }
     // NB: The buffer sizes are static, so even though they might be accessed
     //     in another thread it's safe to measure them.
     amount += m_accumulationBuffer.sizeOfExcludingThis(aMallocSizeOf);
     amount += m_inputBuffer.sizeOfExcludingThis(aMallocSizeOf);
     // Possible future measurements:
     // - m_backgroundThread
     // - m_backgroundThreadLock
     // - m_backgroundThreadCondition
     return amount;
 }
 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

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content/media/webaudio/blink/ReverbConvolver.cpp@b8a032363ba2 (annotated)

content/media/webaudio/blink/ReverbConvolver.cpp