Re: Controlling and reading a usb radio

[Vincent P. <plr...@gm...>]

Le dimanche 13 mai 2012 11:17:16, Vincent Pelletier a écrit :
> Le dimanche 13 mai 2012 06:29:44, Deron a écrit :
> > But
> > 
> > arecord -D "plughw:CARD=Radio" -f cd >audio.raw
> > 
> > Give me static. Ok, but a simple little program using hidapi appears to
> > set the freq, but all I get are "clicks" in the arecord output that
> > conincide with the attempts to change the frequency. I even tried
> > looping through all frequencies every ten seconds but no go.
> 
> FWIW, I have a similar experience with a radio part on a PCI tv card. When
> I enable FM tuner and loop the card's audio dev to speakers, I get
> static-ish noise... Until I switch the FM off, at which point I get
> perfect audio until some buffer runs out of data (ie, half a second, by
> hear).
> I suspect there is a bug in some ring buffer access, where writing would
> overwrite not-read-yet data, or where updating write pointer would
> interfere with read pointer. But I'm not sure where to look.

And I was wrong.
The solution to this problem is to use "fm -T forever on" so "fm" keeps the 
device opened - otherwise, tuner is put to sleep but sound is not muted, 
resulting in static noise.

-- 
Vincent Pelletier