[pvrusb2] pvrusb2-mci-20070114 radio support - stereo?

Mike Isely isely at isely.net
Fri Jan 19 00:54:22 CST 2007

On Thu, 18 Jan 2007, Rick Macdonald wrote:

> I just did a test and I could change the volume with ctl_volume, so things
> are working in that respect. I found ctl_audio_mode and ctl_mpeg_audio_mode.
> Both cur_vals were Stereo. I can set them to Mono and they report Mono,
> but switching them back and forth didn't get me stereo.
> I think I'll load the Windows software somewhere and see if I can get Stereo
> from the USB2 on a Windows machine. I could also boot this Linux box into
> the WinXP MCE that came with it. With two 250 GB drives, I left the 
> factory installed
> Windows there but haven't ever actually run it. It would be interesting 
> to see
> if the PVR-150 is indeed mono as I suspect (just because of the specs on 
> their website).

OK, I tried a couple things.

First, I have 3 PVR USB2 devices here of various ages.  So I looked at 
the packaging.  The newest two devices have the same box, while the 
oldest device was packaged in a box with different artwork on it (same 
size box however).  On that old box, I found one spot where it says 
this: "125 channel cable ready TV tuner and FM stereo radio receiver".  
However on the other two boxes the best I could find just had "FM radio 

I listened briefly to FM radio (using mplayer) on a model 29032 device 
(one of the newer ones).  You're right.  It's mono.

Wondering if perhaps the stereo FM capability had been lost during a 
"cost reduction" for the newer devices, I pulled my oldest device out of 
my mythtv setup and tried its FM radio.  (This was the device that 
arrived in the packaging that said "FM stereo radio receiver".)  Result? 
Same as before: mono audio for the FM radio.

This could very well be a bug in the V4L chip-level driver for the 
demodulator.  Or it could be that the FM radio simply doesn't work in 
stereo (which would be rather astounding).  There are a few other leads 
to chase here.  I'm going to try this same experiment under Windows.  
If someone would like to try that first, I'd welcome hearing about the 
result.  Before I can try this under Windows, I've got to reinstall the 
WinTV package and drivers under Windows.  I haven't had to run this 
under Windows for quite a while and have since replaced all the hardware 
and reinstalled the operating system.  (For me the half-life of a stable 
Windows installation seems to be about 6 months.  Stupid P.O.S.)


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