This is needed for the doppler effect for the AudioPannerNode, since the doppler shift is applied by changing the |playbackRate| of the AudioBufferSourceNode.

Note that the doppler shift is an additional rate multiplier and its value should not be reflected through the playbackRate attribute to web content, but this plan makes sense.

This implement the |playbackRate| member of the AudioBufferSourceNode. I'm not sure about the |ConvertAudioParamToTicks| part, but it seems correct when I try, for example, to do a |sourceNode.playbackRate.linearRampToValueAtTime(2, 37.0)|.

Comment on attachment 733770 [details] [diff] [review] Implement the playbackRate property of AudioBufferSourceNode. r= Review of attachment 733770 [details] [diff] [review]: ----------------------------------------------------------------- r=me with the below fixed. ::: content/media/webaudio/AudioBufferSourceNode.cpp @@ +299,5 @@ > } > > + // WebKit treats the playbackRate as a k-rate parameter in their code, > + // despite the spec saying that it should be an a-rate parameter. We treat > + // it as k-rate. Please include a URL to the spec bug here. @@ +487,5 @@ > +AudioBufferSourceNode::SendPlaybackRateToStream(AudioNode* aNode) > +{ > + AudioBufferSourceNode* This = static_cast<AudioBufferSourceNode*>(aNode); > + AudioNodeStream* ns = static_cast<AudioNodeStream*>(This->mStream.get()); > + ns->SetTimelineParameter(AudioBufferSourceNodeEngine::PLAYBACKRATE, *This->mPlaybackRate); You can use AudioNode::SendTimelineParameterToStream like this: AudioBufferSourceNode* This = static_cast<AudioBufferSourceNode*>(aNode); SendTimelineParameterToStream(This, AudioBufferSourceNodeEngine::PLAYBACKRATE, *This->mPlaybackRate); ::: content/media/webaudio/AudioBufferSourceNode.h @@ +56,5 @@ > + } > + void SetPlaybackRate(NonNull<AudioParam> aPlaybackRate) > + { > + mPlaybackRate = aPlaybackRate.get(); > + } Drop the setter please. ::: content/media/webaudio/WebAudioUtils.cpp @@ +28,5 @@ > + GraphTime graphTime = This->mSourceStream->StreamTimeToGraphTime(streamTime); > + destinationStreamTime = This->mDestinationStream->GraphTimeToStreamTime(graphTime); > + } else { > + destinationStreamTime = This->mDestinationStream->GetCurrentPosition(); > + } You should rebase this on top of my patch in bug 857790. @@ +46,5 @@ > } > > +void > +WebAudioUtils::ConvertAudioParamToTicks(AudioParamTimeline& aParam, > + AudioNodeStream* aDest) I'm not sure why you need this override. Just pass nullptr to the source argument in the other override and get rid of this one please. ::: dom/webidl/AudioBufferSourceNode.webidl @@ +25,3 @@ > attribute AudioBuffer? buffer; > > + attribute AudioParam playbackRate; Argh, this should be a read-only attribute. I fixed the spec.

Backed out because of mochitest-1 crashes: https://hg.mozilla.org/integration/mozilla-inbound/rev/8cf0185087b2

Mass moving Web Audio bugs to the Web Audio component. Filter on duckityduck.