From alsa-user-owner@alsa.jcu.cz  Wed Feb 10 04:59:58 1999
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Date: Thu, 11 Feb 1999 02:01:25 +1100
From: James Gregory <pgregory@thepla.net>
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To: alsa-user@alsa.jcu.cz
Subject: Re: recording: arecord to stdout? suggestions for real-time compression?
References: <8790e7yo7w.fsf@raven.localhost>
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I could be wrong, I don't have bladeenc on this machine, but as far as
I know, bladeenc can read stdin, I used to use it to code direct from CD's
using CD-paranoia, I didn't think that blade wrote to stdout though, not
without another switch, that could well be your problem, read the docs
about bladeenc.

Regards,

Jim.

Rob Browning wrote:

> I'm trying to set up my machine to record some things from the radio,
> and I came up with a couple of questions.  Ideally, what I'd like to
> do is (yes I know that CD quality is overkill for radio...):
>
>   arecord -m -t 1800 - | BladeEnc -b 256 - > something.mp3
>
> However, there are three problems with this:
>
>   1) arecord doesn't seem to be able to redirect it's output to
>      stdout.  Is this intentional, or is it just something no-one's
>      gotten around to?  If the latter, I'd be happy to volunteer to
>      fix it.
>
>   2) BladeEnc doesn't seem to be able to read from a pipe.  I don't
>      know if this is a limitation of the algorithm used to generate
>      mp3's (i.e. you have to see the whole file before you can
>      encode), or a limitation of the program.  Either way, since it's
>      closed-source :< (right now, though I thought I heard that was
>      changing), I couldn't fix it.
>
>   3) My machine's not quite fast enough to run BladeEnc in real time,
>      it's about 30% too slow (so close :>  I bet a good Alpha could
>      handle it easily).
>
> So, for now, I'd just like to fix arecord to write to stdout (and
> perhaps I'll fix aplay to read from stdin -- real-time filters
> anyone?) and then use some lighter weight compression program.  I know
> I could do:
>
>   arecord -m -t 1800 - | gzip -9v > something.cdq.gz
>
> which would get a little compression (so far seems like ~10%), but
> that's far from the best (even lossless) algorithm for sound.  Is
> there something better already available?
>
> (BTW, I have a SoundBlaster 128, which claims hardware Mu-Law.  I'm
>  pretty sound file format ignorant.  (Is there a "FAQ" somewhere?)  I
>  didn't know if Mu-Law would be useful -- I had heard it was only for
>  low-quality recording.  Is that true?  What about the other formats?
>
>     -p <type>     compression type (alaw, ulaw, adpcm)
>
>  Do they only apply if your hardware supports them?
>  )
>
> Thanks
>
> --
> Rob Browning <rlb@cs.utexas.edu> PGP=E80E0D04F521A094 532B97F5D64E3930
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