content/media/webaudio/ChannelSplitterNode.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim:set ts=2 sw=2 sts=2 et cindent: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "mozilla/dom/ChannelSplitterNode.h"
   8 #include "mozilla/dom/ChannelSplitterNodeBinding.h"
   9 #include "AudioNodeEngine.h"
  10 #include "AudioNodeStream.h"
  11 #include "mozilla/PodOperations.h"
  12
  13 namespace mozilla {
  14 namespace dom {
  15
  16 NS_IMPL_ISUPPORTS_INHERITED0(ChannelSplitterNode, AudioNode)
  17
  18 class ChannelSplitterNodeEngine : public AudioNodeEngine
  19 {
  20 public:
  21   ChannelSplitterNodeEngine(ChannelSplitterNode* aNode)
  22     : AudioNodeEngine(aNode)
  23   {
  24     MOZ_ASSERT(NS_IsMainThread());
  25   }
  26
  27   virtual void ProduceAudioBlocksOnPorts(AudioNodeStream* aStream,
  28                                          const OutputChunks& aInput,
  29                                          OutputChunks& aOutput,
  30                                          bool* aFinished) MOZ_OVERRIDE
  31   {
  32     MOZ_ASSERT(aInput.Length() == 1, "Should only have one input port");
  33
  34     aOutput.SetLength(OutputCount());
  35     for (uint16_t i = 0; i < OutputCount(); ++i) {
  36       if (i < aInput[0].mChannelData.Length()) {
  37         // Split out existing channels
  38         AllocateAudioBlock(1, &aOutput[i]);
  39         AudioBlockCopyChannelWithScale(
  40             static_cast<const float*>(aInput[0].mChannelData[i]),
  41             aInput[0].mVolume,
  42             static_cast<float*>(const_cast<void*>(aOutput[i].mChannelData[0])));
  43       } else {
  44         // Pad with silent channels if needed
  45         aOutput[i].SetNull(WEBAUDIO_BLOCK_SIZE);
  46       }
  47     }
  48   }
  49 };
  50
  51 ChannelSplitterNode::ChannelSplitterNode(AudioContext* aContext,
  52                                          uint16_t aOutputCount)
  53   : AudioNode(aContext,
  54               2,
  55               ChannelCountMode::Max,
  56               ChannelInterpretation::Speakers)
  57   , mOutputCount(aOutputCount)
  58 {
  59   mStream = aContext->Graph()->CreateAudioNodeStream(new ChannelSplitterNodeEngine(this),
  60                                                      MediaStreamGraph::INTERNAL_STREAM);
  61 }
  62
  63 JSObject*
  64 ChannelSplitterNode::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aScope)
  65 {
  66   return ChannelSplitterNodeBinding::Wrap(aCx, aScope, this);
  67 }
  68
  69 }
  70 }
  71