Sound help for compleat novice

Arne Wörner arne_woerner at yahoo.com
Mon May 24 12:22:19 PDT 2004


> The sound works just fine when playing CDs or MP3 files, but how does one
> record?  Not knowing any better, I plugged the audio source into the
> mic input, and just did a "cat /dev/audio".
>
> What I seemed to end up with was a raw .AU file, which few programs can
> recognise (I tried SoX and Audacity).  If I copy it back to /dev/audio, I
> hear the original, but I have a feeling that I'm missing something.
>
> So, is there a "better" way?  I'd be looking to produce MP3 or WAV.
>
I like esound's esdrec (after a `mixer =rec cd` or so).
Then I pipe the output into vorbis-tools's oggenc:
  rtprio 10 /usr/local/bin/esdrec -r 44100 | rtprio 11 ./rdau | \
        rtprio 30 /usr/local/bin/oggenc -R 44100 --resample 16000 \
                -M 20 -C 2 -q -1 -Q - > au.ogg &
(I developed rdau, which tracks and corrects the bytes per second, because it
felt like esdrec produces slightly more or less than 44100 samples per second
if you look at it over several hour (e. g. when one records tv movies)).

vorbis-tools's ogg format is quite space-efficient (just like mp3), I think.

The package "nas" should be able to convert raw audio data to wav audio data.

-Arne



	
		
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