Subject: Re: [ecasound] delta 1010,ecasound and recording to wav
From: H. T Hind (hirh_AT_comcast.net)
Date: Wed Oct 29 2003 - 03:55:58 EET
On Wed, Oct 29, 2003 at 12:59:31AM +0200, Kai Vehmanen wrote:
> On Mon, 27 Oct 2003, H. T. Hind wrote:
>
> > I'm able to record using the above samples directly to mp3 files
> > on at least 3 channels. As someone suggested on this list,
> > encoding to mp3 on the fly chews up a lot of CPU which might
> > result in Xruns. To avoid that, I'm trying to record to a wav
> > file at a lower bitrate.
>
> The CPU load is only one source for xruns. In theory (and on well-tuned
> machines, even in practise) you can do audio processing without xruns even
> with very high CPU loads. You can get pretty far just by running ecasound
> as root and specifying "-r" (and jackd too (-R) if you are using it).
In production, I'd like the ability to record 8 channels
simultaneously , each recording to individual files.
I will try ecasound with -r option with 4 channels.
> If you still want to try lowering the CPU load, you'll get the biggest
> savings when you move from mp3 output to wav output. From there, lowering
> the quality of written wav files does not help as much. Anyways, you can
> still do it:
The lowering is reduce disk space. In the wav format ecasound
hardly takes up CPU time. The default format of 32,1,44100
generates huge files and I want to be able record 24/7 if
necessary.
> > ecasound -f:32,1,44100 -G:jack,ecasound,recv -a:1 -i jack -o
> > ~/1.wav -a:2 -i jack -o ~/2.wav -a:3 -i jack -o
> > ~/3.wav -a:4 -i jack -o ~/4.wav
> Replace -f:32,1,44100 with -f:16,1,44100 is one example.
Often this produces big gaps (silence) in the beginning of the files.
Any idea how I can fix that ?
> > Is there a way to get ecasound to start writing to another file
> > while still recording ? Ideally, I'd like to have the ecasound
> > process start recording and then write to another file(s) at a
> > configurable amount of time. Is it possible ?
>
> Hmm, so do you want to write the same material to multiple files, or do
> you want to discard the start of the recorded material, or only write
> to a file for a certain period of time? Ecasound can do all these things,
> but the syntax varies from case to case.
As the files need to be post processed and to be
converted to a streaming format, I wanted the ability to write
the files in say 1 hour chunks, so post processing can happen
alongside. I can't directly change into streaming format as I
need either wav or mp3 for post processing.
If I could downsample to wav format while still conserving disk
space, it would be idea. I can then compress the audio to rm and
delete the wav files or mp3 files.
-- hth
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