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Re: DynamicsCompressorNode.reduction is read-only AudioParam ?

From: Paul Adenot <paul@paul.cx>
Date: Wed, 28 Aug 2013 19:32:05 +0200
Message-ID: <521E3415.1070903@paul.cx>
To: public-audio@w3.org
If we don't want to make connect work from an AudioParam to an
AudioParam, and because side-chaining is a specific but very useful
construct, we could simply add some way to feed in data in the
CompressorNode, as it's usually done in a side-chain setup: input
channel 0-x, sound data to be compressed, input channel (x+1)-z, sound
data that determine the compression level.

We would still make the reduction a read only float, because it would
really be a monitoring value.

I think this would address the need, be easy to implement/use, and match
the behaviour of DAWs.

Paul.

On 28/08/2013 18:37, Chris Wilson wrote:
> Incidentally, I believe the reason is related to side-chain compression;
> I'd had a conversation with Chris about this a while ago, and his take
> was that sidechain compression could be done by assigning the .value of
> a gainNode.gain to the AudioParam output of reduction.  This does not
> work (IIRC) in Blink/webkit, and AFAIK, nowhere else do you assign
> audioparam.value to an audioparam and expect it to make a
> connect()ion-like connection.
> 
> I do think we must design sidechain compression into the
> DynamicCompressor before we finish off v1, so I'd like to consider that
> together with this change.  Sidechain (ducking, de-essing, etc) is
> incredibly common.
> 
> 
> On Wed, Aug 28, 2013 at 9:29 AM, Ehsan Akhgari <ehsan.akhgari@gmail.com
> <mailto:ehsan.akhgari@gmail.com>> wrote:
> 
>     This has been discussed in
>     <http://lists.w3.org/Archives/Public/public-audio/2013AprJun/0181.html>,
>     and we agreed that it should be a readonly float.  Paul, can you
>     please make that change, if nobody objects?  I'd like us to fix
>     Gecko based on that as soon as possible if we change the spec here.
> 
>     --
>     Ehsan
>     <http://ehsanakhgari.org/>
> 
> 
>     On Tue, Aug 27, 2013 at 10:30 AM, s p <sebpiq@gmail.com
>     <mailto:sebpiq@gmail.com>> wrote:
> 
>         Hi,
> 
>         DynamicsCompressorNode.reduction is specified to be a monitor
>         value, so read-only, but the interface says it's an AudioParam
>         (https://dvcs.w3.org/hg/audio/raw-file/tip/webaudio/specification.html#DynamicsCompressorNode-section).
>         So my question is what is the point in having a read-only
>         AudioParam?
> 
>         Sebastien Piquemal
> 
> 
> 
Received on Wednesday, 28 August 2013 19:13:52 UTC

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