[LAD] Multi-Channel channel order

[Fons Adriaensen]

On Fri, Aug 14, 2009 at 12:36:36PM -0400, David Robillard wrote:

> Is there any existing 'standard' for the order of channels for
> higher-than-stereo multi-channel streams?
> 
> ...
> 
> For example, for discrete non-interleaved 5.1 (using a full channel for
> the .1) we have 6 channels: left, center, right, rear left, rear right,
> LFE (see http://lv2plug.in/ns/dev/port-groups#FivePointOneGroup)
> 
> What order should these be passed in?  Any existing practices?

For 5.1 there are several orders in use. Same for AMB, in 
particular higher order.

But: either it doesn't matter (e.g. for EQ), and where it does
matter a 'general' multichannel plugin (i.e. an essentially mono
one that knows about the multichannel port extension and can
replicate its internals) probably can't do the job anyway, and
you need a dedicated plugin.

That would be the case for e.g. an AMB compressor that would
apply the same gain to all channels, but derive it only from
one of them (W).  

What is important is that a dedicated 5.1 plugin should be 
compatible to a 'general' one that has 'anonymous' or just
numbered channels, and configured for 6 channels.

Also, e.g. an EQ that can be set to six channels should
work as well *any* 6-ch format. Which means that in that
case channel names are not a property of the plugin, but
of the host.

For a dedicated 5.1 or AMB plugin that would be different.

This suggest that there would some form of trying to match
a port defined by the host to that provided by the plugin.
If they are identical, all is OK, but that would not be
the only case, some other combinations have to work as well.

Ciao,

-- 
FA

Io lo dico sempre: l'Italia è troppo stretta e lunga.