Re: [ecasound] channel manipulation

From: Patrick Shirkey <pshirkey@email-addr-hidden>
Date: Wed Sep 26 2012 - 14:34:57 EEST

On Wed, September 26, 2012 7:30 pm, Julien Claassen wrote:
> Hello Patrick!
> Untested, but should work:

Can you help me make a little more sense of this please?

> ecasound -f:16,3,44100 -a:1,2,3 -i test.wav \
> -a:1 -chmix:1 \

mix channel 1 and 2 (stereo mixdown to mono)

> -a:2 -chmute:2 -chmove:1,2 \

mute channel 2 (right input) and move channel 1 (left) to output channel 2
- (left mono)

> -a:3 -chmute:1 -ea:-100 -chmove:2,3

mute channel 1 (left input), invert signal and move channel 2 (right
input) to output channel 3 - (right mono inverted)

> -a:all -o test-out.wav

output channels 1,2,3 to wav file.

> Will generate a 3-channel output wav, with: ch1: mono-mixdown of right
> and
> left. ch2: left channel, ch3: right channel inverted.
> I think you wanted a mix of the right inverted channel with the left?
> So in
> -a:3 use a -chcopy:3,2 at the end.


    -a:3 -chmute:1 -ea:-100 -chcopy:3,2

mute channel 1 (input), invert signal and copy channel 3 to channel 2

Is the result any different if I use this instead?

    -a:3 -chmute:1 -ea:-100 -chmix:2,3

> If you want the normal right channel as well, it will be four chains,
> in in
> chain 3, you will have:
> -a:3 -chmute:1 -ea:-100
> and in chain 4, the normal right:
> -a:4 -chmute:1 -chmove:2,3
> Though, depending on what you expect as output volumes, I'd use an
> overall
> decrease in amplitude. So at the beginning, directly after test.wav have
> something like -ea:50 .

That's my next trick. First I want to build the signal path then I will
start on the filters.

> I hope this helps. It looks a lot like you want to have this strange
> surround stereo format, that some CDs use and that I hadn't been able to
> decode once. :-)

I'm actually going a bit further than that but one step at a time :-)

Patrick Shirkey
Boost Hardware Ltd
Live Security Virtual Conference
Exclusive live event will cover all the ways today's security and 
threat landscape has changed and how IT managers can respond. Discussions 
will include endpoint security, mobile security and the latest in malware 
Ecasound-list mailing list
Received on Wed Sep 26 16:15:03 2012

This archive was generated by hypermail 2.1.8 : Wed Sep 26 2012 - 16:15:03 EEST