The Tor Browser: content/media/AudioSegment.h@44a2da4a2ab2 (annotated)

content/media/AudioSegment.h@44a2da4a2ab2 (annotated)

content/media/AudioSegment.h

Fri, 16 Jan 2015 04:50:19 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Fri, 16 Jan 2015 04:50:19 +0100
branch: TOR_BUG_9701
changeset 13: 44a2da4a2ab2
permissions: -rw-r--r--

Replace accessor implementation with direct member state manipulation, by
request https://trac.torproject.org/projects/tor/ticket/9701#comment:32

 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* 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/. */
 #ifndef MOZILLA_AUDIOSEGMENT_H_
 #define MOZILLA_AUDIOSEGMENT_H_
 #include "MediaSegment.h"
 #include "AudioSampleFormat.h"
 #include "SharedBuffer.h"
 #include "WebAudioUtils.h"
 #ifdef MOZILLA_INTERNAL_API
 #include "mozilla/TimeStamp.h"
 #endif
 namespace mozilla {
 template<typename T>
 class SharedChannelArrayBuffer : public ThreadSharedObject {
 public:
   SharedChannelArrayBuffer(nsTArray<nsTArray<T> >* aBuffers)
   {
     mBuffers.SwapElements(*aBuffers);
   }
   virtual size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const MOZ_OVERRIDE
   {
     size_t amount = 0;
     amount += mBuffers.SizeOfExcludingThis(aMallocSizeOf);
     for (size_t i = 0; i < mBuffers.Length(); i++) {
       amount += mBuffers[i].SizeOfExcludingThis(aMallocSizeOf);
     }
     return amount;
   }
   virtual size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const MOZ_OVERRIDE
   {
     return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
   }
   nsTArray<nsTArray<T> > mBuffers;
 };
 class AudioStream;
 class AudioMixer;
 /**
  * For auto-arrays etc, guess this as the common number of channels.
  */
 const int GUESS_AUDIO_CHANNELS = 2;
 // We ensure that the graph advances in steps that are multiples of the Web
 // Audio block size
 const uint32_t WEBAUDIO_BLOCK_SIZE_BITS = 7;
 const uint32_t WEBAUDIO_BLOCK_SIZE = 1 << WEBAUDIO_BLOCK_SIZE_BITS;
 void InterleaveAndConvertBuffer(const void** aSourceChannels,
                                 AudioSampleFormat aSourceFormat,
                                 int32_t aLength, float aVolume,
                                 int32_t aChannels,
                                 AudioDataValue* aOutput);
 /**
  * Given an array of input channels (aChannelData), downmix to aOutputChannels,
  * interleave the channel data. A total of aOutputChannels*aDuration
  * interleaved samples will be copied to a channel buffer in aOutput.
  */
 void DownmixAndInterleave(const nsTArray<const void*>& aChannelData,
                           AudioSampleFormat aSourceFormat, int32_t aDuration,
                           float aVolume, uint32_t aOutputChannels,
                           AudioDataValue* aOutput);
 /**
  * An AudioChunk represents a multi-channel buffer of audio samples.
  * It references an underlying ThreadSharedObject which manages the lifetime
  * of the buffer. An AudioChunk maintains its own duration and channel data
  * pointers so it can represent a subinterval of a buffer without copying.
  * An AudioChunk can store its individual channels anywhere; it maintains
  * separate pointers to each channel's buffer.
  */
 struct AudioChunk {
   typedef mozilla::AudioSampleFormat SampleFormat;
   // Generic methods
   void SliceTo(TrackTicks aStart, TrackTicks aEnd)
   {
     NS_ASSERTION(aStart >= 0 && aStart < aEnd && aEnd <= mDuration,
                  "Slice out of bounds");
     if (mBuffer) {
       MOZ_ASSERT(aStart < INT32_MAX, "Can't slice beyond 32-bit sample lengths");
       for (uint32_t channel = 0; channel < mChannelData.Length(); ++channel) {
         mChannelData[channel] = AddAudioSampleOffset(mChannelData[channel],
             mBufferFormat, int32_t(aStart));
       }
     }
     mDuration = aEnd - aStart;
   }
   TrackTicks GetDuration() const { return mDuration; }
   bool CanCombineWithFollowing(const AudioChunk& aOther) const
   {
     if (aOther.mBuffer != mBuffer) {
       return false;
     }
     if (mBuffer) {
       NS_ASSERTION(aOther.mBufferFormat == mBufferFormat,
                    "Wrong metadata about buffer");
       NS_ASSERTION(aOther.mChannelData.Length() == mChannelData.Length(),
                    "Mismatched channel count");
       if (mDuration > INT32_MAX) {
         return false;
       }
       for (uint32_t channel = 0; channel < mChannelData.Length(); ++channel) {
         if (aOther.mChannelData[channel] != AddAudioSampleOffset(mChannelData[channel],
             mBufferFormat, int32_t(mDuration))) {
           return false;
         }
       }
     }
     return true;
   }
   bool IsNull() const { return mBuffer == nullptr; }
   void SetNull(TrackTicks aDuration)
   {
     mBuffer = nullptr;
     mChannelData.Clear();
     mDuration = aDuration;
     mVolume = 1.0f;
     mBufferFormat = AUDIO_FORMAT_SILENCE;
   }
   int ChannelCount() const { return mChannelData.Length(); }
   size_t SizeOfExcludingThisIfUnshared(MallocSizeOf aMallocSizeOf) const
   {
     return SizeOfExcludingThis(aMallocSizeOf, true);
   }
   size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf, bool aUnshared) const
   {
     size_t amount = 0;
     // Possibly owned:
     // - mBuffer - Can hold data that is also in the decoded audio queue. If it
     //             is not shared, or unshared == false it gets counted.
     if (mBuffer && (!aUnshared || !mBuffer->IsShared())) {
       amount += mBuffer->SizeOfIncludingThis(aMallocSizeOf);
     }
     // Memory in the array is owned by mBuffer.
     amount += mChannelData.SizeOfExcludingThis(aMallocSizeOf);
     return amount;
   }
   TrackTicks mDuration; // in frames within the buffer
   nsRefPtr<ThreadSharedObject> mBuffer; // the buffer object whose lifetime is managed; null means data is all zeroes
   nsTArray<const void*> mChannelData; // one pointer per channel; empty if and only if mBuffer is null
   float mVolume; // volume multiplier to apply (1.0f if mBuffer is nonnull)
   SampleFormat mBufferFormat; // format of frames in mBuffer (only meaningful if mBuffer is nonnull)
 #ifdef MOZILLA_INTERNAL_API
   mozilla::TimeStamp mTimeStamp;           // time at which this has been fetched from the MediaEngine
 #endif
 };
 /**
  * A list of audio samples consisting of a sequence of slices of SharedBuffers.
  * The audio rate is determined by the track, not stored in this class.
  */
 class AudioSegment : public MediaSegmentBase<AudioSegment, AudioChunk> {
 public:
   typedef mozilla::AudioSampleFormat SampleFormat;
   AudioSegment() : MediaSegmentBase<AudioSegment, AudioChunk>(AUDIO) {}
   // Resample the whole segment in place.
   template<typename T>
   void Resample(SpeexResamplerState* aResampler, uint32_t aInRate, uint32_t aOutRate)
   {
     mDuration = 0;
     for (ChunkIterator ci(*this); !ci.IsEnded(); ci.Next()) {
       nsAutoTArray<nsTArray<T>, GUESS_AUDIO_CHANNELS> output;
       nsAutoTArray<const T*, GUESS_AUDIO_CHANNELS> bufferPtrs;
       AudioChunk& c = *ci;
       // If this chunk is null, don't bother resampling, just alter its duration
       if (c.IsNull()) {
         c.mDuration = (c.mDuration * aOutRate) / aInRate;
         mDuration += c.mDuration;
         continue;
       }
       uint32_t channels = c.mChannelData.Length();
       output.SetLength(channels);
       bufferPtrs.SetLength(channels);
       uint32_t inFrames = c.mDuration;
       // Round up to allocate; the last frame may not be used.
       NS_ASSERTION((UINT32_MAX - aInRate + 1) / c.mDuration >= aOutRate,
                    "Dropping samples");
       uint32_t outSize = (c.mDuration * aOutRate + aInRate - 1) / aInRate;
       for (uint32_t i = 0; i < channels; i++) {
         const T* in = static_cast<const T*>(c.mChannelData[i]);
         T* out = output[i].AppendElements(outSize);
         uint32_t outFrames = outSize;
         dom::WebAudioUtils::SpeexResamplerProcess(aResampler, i,
                                                   in, &inFrames,
                                                   out, &outFrames);
         MOZ_ASSERT(inFrames == c.mDuration);
         bufferPtrs[i] = out;
         output[i].SetLength(outFrames);
       }
       MOZ_ASSERT(channels > 0);
       c.mDuration = output[0].Length();
       c.mBuffer = new mozilla::SharedChannelArrayBuffer<T>(&output);
       for (uint32_t i = 0; i < channels; i++) {
         c.mChannelData[i] = bufferPtrs[i];
       }
       mDuration += c.mDuration;
     }
   }
   void ResampleChunks(SpeexResamplerState* aResampler);
   void AppendFrames(already_AddRefed<ThreadSharedObject> aBuffer,
                     const nsTArray<const float*>& aChannelData,
                     int32_t aDuration)
   {
     AudioChunk* chunk = AppendChunk(aDuration);
     chunk->mBuffer = aBuffer;
     for (uint32_t channel = 0; channel < aChannelData.Length(); ++channel) {
       chunk->mChannelData.AppendElement(aChannelData[channel]);
     }
     chunk->mVolume = 1.0f;
     chunk->mBufferFormat = AUDIO_FORMAT_FLOAT32;
 #ifdef MOZILLA_INTERNAL_API
     chunk->mTimeStamp = TimeStamp::Now();
 #endif
   }
   void AppendFrames(already_AddRefed<ThreadSharedObject> aBuffer,
                     const nsTArray<const int16_t*>& aChannelData,
                     int32_t aDuration)
   {
     AudioChunk* chunk = AppendChunk(aDuration);
     chunk->mBuffer = aBuffer;
     for (uint32_t channel = 0; channel < aChannelData.Length(); ++channel) {
       chunk->mChannelData.AppendElement(aChannelData[channel]);
     }
     chunk->mVolume = 1.0f;
     chunk->mBufferFormat = AUDIO_FORMAT_S16;
 #ifdef MOZILLA_INTERNAL_API
     chunk->mTimeStamp = TimeStamp::Now();
 #endif
   }
   // Consumes aChunk, and returns a pointer to the persistent copy of aChunk
   // in the segment.
   AudioChunk* AppendAndConsumeChunk(AudioChunk* aChunk)
   {
     AudioChunk* chunk = AppendChunk(aChunk->mDuration);
     chunk->mBuffer = aChunk->mBuffer.forget();
     chunk->mChannelData.SwapElements(aChunk->mChannelData);
     chunk->mVolume = aChunk->mVolume;
     chunk->mBufferFormat = aChunk->mBufferFormat;
 #ifdef MOZILLA_INTERNAL_API
     chunk->mTimeStamp = TimeStamp::Now();
 #endif
     return chunk;
   }
   void ApplyVolume(float aVolume);
   void WriteTo(uint64_t aID, AudioStream* aOutput, AudioMixer* aMixer = nullptr);
   int ChannelCount() {
     NS_WARN_IF_FALSE(!mChunks.IsEmpty(),
         "Cannot query channel count on a AudioSegment with no chunks.");
     // Find the first chunk that has non-zero channels. A chunk that hs zero
     // channels is just silence and we can simply discard it.
     for (ChunkIterator ci(*this); !ci.IsEnded(); ci.Next()) {
       if (ci->ChannelCount()) {
         return ci->ChannelCount();
       }
     }
     return 0;
   }
   static Type StaticType() { return AUDIO; }
   virtual size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const MOZ_OVERRIDE
   {
     return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
   }
 };
 }
 #endif /* MOZILLA_AUDIOSEGMENT_H_ */

The Tor Browser / annotate

content/media/AudioSegment.h@44a2da4a2ab2 (annotated)

content/media/AudioSegment.h