Subject: Re: [linux-audio-user] offline processing
From: Chris Pickett (chris.pickett_AT_mail.mcgill.ca)
Date: Tue Feb 17 2004 - 08:23:24 EET
Erik de Castro Lopo wrote:
> On Mon, 16 Feb 2004 20:28:59 -0500
> Chris Pickett <chris.pickett_AT_mail.mcgill.ca> wrote:
>
>
>>Hi,
>>
>>I've been wondering: what is it like processing audio offline under
>>Linux? Is this something that is widely supported? I did a bunch of
>>google searches using the term "offline" but couldn't find anything
>>really useful.
>>
>>My computer is fairly weak (800 MHz laptop, no DSP card). Currently, if
>>I want to process a file (apply effects, change the sample rate, apply
>>dithering, mix it with another file,
>
>
> Programs like SoX and sndfile-src (a command line sample rate converter
> which is distributed with libsamplerate) do this.
Thanks for the answer, I've now looked at those. It seems that SoX is
limited to the built-in effects and libsamplerate / sndfile-src is just
for converting sample rates (well, you can tell me otherwise if I'm
wrong, you're the author Erik :) ...). It also seems that ecasound can
do the same, at least for native-to-ecasound things.
What about support for offline LADSPA plugin processing, e.g.
command-line through ecasound or from within a full-blown GUI thing like
Rosegarden?
Or, in general, setting up a bunch of applications to produce a final
output file with JACK, but have it all done offline?
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". But ... it's hard to find
explicit mention of offline processing because everybody is so worried
about real-time processing and low latency and all that (understandably
so), whereas I'm not likely to use this machine for live audio (okay, a
little bit of real-time-ness is nice in any setup, and I'm sure my
machine can provide the little I need to edit tracks).
Basically, I would be very happy if somebody could assure me that I
don't have to worry about running /anything/ real-time in Linux audio if
I don't want to, save for recording in and playing out through my sound
card.
Cheers,
Chris
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