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Re: Web Audio API spec review

From: Olli Pettay <Olli.Pettay@helsinki.fi>
Date: Mon, 21 May 2012 14:37:37 +0300
Message-ID: <4FBA2901.5080607@helsinki.fi>
To: robert@ocallahan.org
CC: Chris Wilson <cwilso@google.com>, public-audio@w3.org, Chris Rogers <crogers@google.com>, Philip Jägenstedt <philipj@opera.com>
On 05/21/2012 05:11 AM, Robert O'Callahan wrote:
> I think Olli is talking about defining Web Audio on top of MediaStreams. E.g. the spec could say that an AudioNode behaves just like a MediaStream,
> but with certain extra features.

Right, though the exact details are still unknown.
AudioNodes could basically add some utility/helper methods to MediaStream objects,
or behave as stream processors (apply some effects etc).
The API for JS should stay pretty similar.

interface AudioNode : MediaStream


> If we don't do that, then specifying all the interactions between AudioNodes and MediaStreams (and any other media-stream-like abstractions created
> later) could get a lot more difficult. For example we still have unresolved questions about maintaining synchronization in combinations of AudioNodes
> and MediaStreams. Another case is cycles in the graph. Cycles of AudioNodes are allowed; what about cycles of MediaStreams? What if someone creates a
> cycle involving both AudioNodes and MediaStreams?
> Another danger is that in the future features get added to AudioNodes and MediaStreams independently which cause problems when the frameworks are
> mingled. This danger is mitigated if they share underlying definitions.
> BTW since I realized last week that Web Audio allows cycles in the graph, I've been studying the interaction of cycles (with delay) with the features
> of MediaStreams Processing (pausing of individual streams, buffering to maintain synchronization in the presence of high-delay processing nodes,
> synchronized cueing of arbitrary streams) using formal methods. Some combinations of these features have unresolvable problems. I'll have more to say
> when I've done some more analysis.
> Rob
> --
> “You have heard that it was said, ‘Love your neighbor and hate your enemy.’ But I tell you, love your enemies and pray for those who persecute you,
> that you may be children of your Father in heaven. ... If you love those who love you, what reward will you get? Are not even the tax collectors doing
> that? And if you greet only your own people, what are you doing more than others?" [Matthew 5:43-47]
Received on Monday, 21 May 2012 11:38:52 UTC

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