[MPlayer-dev-eng] [RFC] multichannel ladspa plugin support

[Reimar Döffinger]

Hello,
a really old subject...

On Wed, Jan 24, 2007 at 02:15:26PM +0100, Ivo wrote:
> On Friday 05 January 2007 14:57, Reimar Döffinger wrote:
> > attached is a completely untested patch that might add support for that.
> > Maybe someone can check it or give me a tip how to best test it.
> > Even if for some reason it does not work like this, some of the changes
> > IMHO really deobfuscate the code a bit.
> 
> Sorry it took me so long to respond, but I was a bit behind with reading the 
> mailinglist.
> 
> The deobfuscation looks good and by the looks of it the functionality 
> remains exactly the same for 1ch and 2ch input/output. Also, with n channel 
> input and mono filters, everything looks fine. Same for n channel input and 
> m channel filters where n == m or where n !=m and (n % m) == 0. But I think 
> there might be a problem where n != m and (n % m) != 0 . For example:
> 
> 5 ch input --> 2 ch filter. This creates three filter instances. The first 
> two have both inputs connected, but the third one has only its left channel 
> connected. This might cause the filter to crash as it is one input/output 
> bufferpair short.

I think that's not the case, the old code already had to deal with this
for 2 channel filter and one channel input.
The code around line 888 just duplicates the last channel so everything
is connected - obviously this might cause the filter to not work as
expected, but well, you can't have everything *g*

> I recently re-installed my system from scratch (literally, I built LFS) and 
> I do not have any ladspa filters installed atm. Furthermore, I do not have 
> a soundcard capable of more than two channels, so it's a bit of a pain to 
> test it correctly. To test it, you can have a look at:

I don't have a useful soundcard for this stuff

> http://www.ladspa.org/  (the SDK, plus a link to CMT, which is a reasonably 
> nice collection of filters, though some are pretty broken)
> http://tap-plugins.sourceforge.net/index.html  (imho the best plugins)

None are obviously for more than two channels...
I think it can't really break anything, so applied.

Greetings,
Reimar Döffinger