[linux-audio-dev] recording, sample rate problem

Turos László Zsolt laci at integrasoft.ro
Tue Mar 18 05:45:00 UTC 2003


Nick Bailey wrote:
> 
> Turos Laszlo wrote:
> 
> >Hi
> >
> >I'm trying to write a soundrecorder application under linux.
> >I have Redhat 7.2 with kernel 2.4.
> >Playing sound on my soundcard works fine,but
> >I'm having problems recording.
> >I was using GNOME Sound recorder 1.2.3 to record sound but it seems
> >that it can only record sound at a 48000 Hz sampling rate,but playing back
> >the recorded sound it is a noise.
> >
> >I wrote a little program myself and I reached the same conclusion that I
> >can not set other sampling rate than 48000.
> >My soundcard under Windows records good sound with other sampling
> >rates.
> >
> >
> You don't know that. You mean "A file with other sampling rates can be
> produced under Windows", right?
Well I used under windows the windows multimedia API(Mmsystem.h).I don't
know if it uses software conversion to produce other sampling rates.Does
it use?
I used the waveInOpen function(under windows of course ) to set the
desired sample rate and open the device.

> 
> >I have my soundcard on my VIA motherboard.
> >
> I don't know this hardware, but you could try using 48k sampling rate
> and converting to different sample rates when saving. Using sox down a
> pipe works pretty well for this (other less hacky solutions exist :). It
> seams a bit strange you can't record at least 44100 and 32000 as well,
> though. What other sampling rates did you try?
I tried all other well-known sample rate 8000,16000,44100 etc.

For example if I want 8000 Hz I should consider from every 6 byte only
the LSB byte
to obtain 8000Hz from 48000 Hz?(if the channel number is the same)
Should this software conversion work?

> 
> >In my harware Browser looks like this:
> >Manufacturer: VIA Technologies
> >Driver:                via82cxxx_audio
> >
> >Can anybody give me a hint?
> >
> >Best regards
> >Laci
> >
> >
> --
> Dr Nick Bailey                              n.j.bailey at elec.gla.ac.uk
> Centre for Music Technology                 http://cmt.gla.ac.uk/
> Dept of Electronics and Electrical Eng      http://www.elec.gla.ac.uk/
> The University of Glasgow                   http://www.gla.ac.uk
> 
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