diff -r 000000000000 -r 6474c204b198 content/media/AudioSegment.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/content/media/AudioSegment.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,294 @@
+/* -*- 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_ */