[linux-audio-dev] Radio Scanner Recorder

Guillaume Filion gfk at logidac.com
Tue Aug 30 15:31:50 UTC 2005

Guillaume Filion a écrit :
>>I'm a in the process of making a police/EMS/fire radio recorder. ...
>>However, I started thinking and found that it would be better to have a 
>>different file for each segment. For example, if there is
>>- 45 seconds of speech, followed by
>>- 3 minutes of silence,  followed by
>>- 2 minutes of speech
>>I would get two files, one 45 seconds long and one 2 minutes long.
>>Does such a program allready exists, and if not, what would be the 
>>best/easiest way of doing it?

Hi and thanks for your responses,

I started playing with batchrec last night with good results. The source 
code is clean and compiled on the first try (on debian).

I tried it on an old 200 MHz PC with 32 MB ram. I made a small perl 
script that runs every 5 minutes from a cron job. The script runs at low 
priority (with nice) and does some post processing on the wav files and 
recompresses them to 16 KHz 24 Kbps Mono MP3 files.

 From time to time, I get a "Input/Output Error" from batchrec, I guess 
this is because of the low system ressources. It might be a good idea to 
do the post processing on another PC.

I'm not really familiar with jack, I took a look at the documentation 
but I would have to invest more time to get something out of it. For 
now, batchrec does the job pretty well. One thing that I would like to 
do would be to use a low pass filter because my scanner seems to emit 
some low frequency sounds that are louder than some parts of the 
conversations. If I understand jack correctly, it would allow me to plug 
a low pass filter in front of the recording program easily.

Anyway, I've made a big step in this project with batchrec, thanks a 
lot! I'll keep you updated.

Guillaume Filion, ing. jr
Logidac Tech., Beaumont, Québec, Canada - http://logidac.com/
PGP Key and more: http://guillaume.filion.org/

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