[linux-audio-user] offline processing

Anahata anahata at treewind.co.uk
Tue Feb 17 03:46:57 EST 2004


On Tue, Feb 17, 2004 at 01:23:24AM -0500, Chris Pickett wrote:
> Erik de Castro Lopo wrote:
> What about support for offline LADSPA plugin processing, e.g. 
> command-line through ecasound or from within a full-blown GUI thing like 
> Rosegarden?
>

I'm not an expert on this, but first there are plenty of applications
that do particular jobs in non-real time - all the MP3 and Ogg Vorbis
tools, for example, and sox has already meen mentioned.

Audacity has plugin support and various effects which are applied in
non-real time. The default action of Audacity with multiple tracks (i.e.
more than a simple stereo pair) is to mix them to stereo. While it does
this in real time when you press the play button, it does the same thing
when you select "export as WAV".

In fact I'd be surprised to find any audio processing application that
can't be persuaded to run effectively as a good old-fashioned 
stdin->stdout filter.

I'm not familiar with ecasound, but I thought it could perform all of
its functions from file to file if you wanted it to.

> From what I can tell, things were built to do this from the ground up, 
> e.g. in the JACK design document there is a picture of jackd and it says 
> "ALSA backend client and clock driver".

I don't think Jack is what you need: as I understand it Jack is all
about realtime audio. I could be very wrong...

-- 
Anahata
anahata at treewind.co.uk       Tel: 01638 720444
http://www.treewind.co.uk    Mob: 07976 263827


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