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Re: limiting channel count through channelCount and channelCountMode limitations, in PannerNode et al.

From: Karl Tomlinson <karlt+public-audio@karlt.net>
Date: Mon, 16 Sep 2013 16:59:43 +1200
To: public-audio@w3.org
Message-ID: <87six5xsxs.fsf@karlt.net>
On Fri, 23 Aug 2013 13:25:04 +1200, Karl Tomlinson wrote:

> Some AudioNodes have limitations on the number of input channels,
> but the computedNumberOfChannels calculation in [1] currently
> doesn't necessarily consider these limitations.
>
> The input channel limitation is clearly spelled out for
> PannerNode, for example: "The audio stream from the input will be
> either mono or stereo, depending on the connection(s) to the
> input."
>
> Would it make sense to spec that an exception is thrown if a
> PannerNode's channelCount is set > 2?

> For channelCount to be effective in limiting the number of input
> channels, channelCountMode cannot be "max".
> Would it make sense to spec that an exception is thrown if a
> PannerNode's channelCountMode is set to "max"?

> [2] implies that a similar situation applies to ConvolverNode,
> and, looking at [3], I wonder whether a similar situation applies
> in ScriptProcessorNode?  See also [4].

> [1] https://dvcs.w3.org/hg/audio/raw-file/tip/webaudio/specification.html#UpMix
> [2]
> https://dvcs.w3.org/hg/audio/raw-file/tip/webaudio/specification.html#Convolution-reverb-effect
> [3] https://www.w3.org/Bugs/Public/show_bug.cgi?id=17534
> [4] http://lists.w3.org/Archives/Public/public-audio/2013JanMar/0136.html

PannerNode and ConvolverNode in Gecko now throw NOT_SUPPORTED_ERR
if an attempt is made to set channelCount to a value > 2 or
channelCountMode to "max".

ScriptProcessorNode throws NOT_SUPPORTED_ERR if an attempt is made
to change channelCount from numberOfInputChannels or to change
channelCountMode from "explicit".
Received on Monday, 16 September 2013 05:00:58 UTC

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