Re: channel manipulation

Helloooo list members and Patrick in particular,

I've been having a lot of fun reading the chatter and trying to fix this 
problem.

On 09/28/2012 03:23 AM, Patrick Shirkey wrote:
> Afaict the channels that take a loop input are not receiving any audio at
> all. Is it possible that the loop input is only wanting a live feed?
>
> I have tried the following:
>
> +++
> Channel 5,6 are silent. Channels 1,2,3,4 have audio but I'm not sure yet
> if they are correct. I want to fix channels 5,6 first.
>
> - Tested output with these two chains to make sure I'm not being stupid:
>
> ecasound -a:1 -i test-out.wav -o alsa
> ecasound -a:1 -i test-out.wav -chmute:1 -chmute:2 -chmute:3 -chmute:4
> -ea:1000 -chmix:1 -o alsa
>
> I can see a very small waveform on channel 5,6 in audacity but there is no
> sound coming from those channels at all.
>
> converter script:
>
> ecasound -t 5 -f:s16_be,6,48000 \
> -a:1,2,3,4,5,6 -i TEST_1-2.aif \
> -a:1 -chmute:2 \
> -a:2 -chmute:1 \
> -a:3 -chmix:3  \
> -a:4 -chmix:4  \
> -a:5 -chmute:1  \
> -a:6 -chmute:2 \
> -a:5,6 -o loop,1 \
> -a:7,8 -i loop,1 \
> -a:7  -ea:200 -chmix:5 \
> -a:8  -chmix:6 \
> -a:all -o test-out.wav
Here's the good bits:

##   you don't want -a:all -o test-out.wav    - you want chain 5 and 6 
to go to the loop device (remember?)
##   you're working on 6 channel chains where you actually want to work 
on 2 channels and do the _mixdown_ to 6 channels

ecasound -t 5 -f:s16_be,2,48000 \
-a:1,2,3,4,5,6 -i TEST_1-2.aif \
-a:1 -chmute:2 \
-a:2 -chmute:1 \
-a:3 -chmix:3 -eac:400,3 \
-a:4 -chmix:4 -eac:400,4 \
-a:5 -chmute:1 \
-a:6 -chmute:2 \
-a:5,6 -o loop,1 \
-a:7,8 -i loop,1 \
-a:7 -chmix:5 -eac:800,5 \
-a:8 -chmix:6 -eac:800,6 \
-a:1,2,3,4,7,8 -f:s16_be,6,48000 -o test-out.wav

I haven't figured out -chmix's behavior, but the -eac's are there to 
counter it's lowering of the volume in this particular set-up.
This probably has its own bugs, is most likely not what you want and 
looks more like a hack than a chain setup.
Nonetheless, this seems to have some audio on channels 5 and 6, which 
you weren't getting before.

Hope this helps,

Cheers,

me





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