PVR-350 and the pvr250 port - report

[Rick C. Petty]

On Wed, Oct 11, 2006 at 11:49:39PM +0200, Torfinn Ingolfsen wrote:
> 
> It was asked on this list if my PVR-350 card worked with the pvr250
> port / driver.
> Here are the results.
> 
> I can then use pvr250-setchannel like this:
> pvr250-setchannel -t -g 720x576
> pvr250-setchannel -m 4 196.25

I thought the -m option was tha channel set for if you specify a channel
(not a frequency)?  You've already set the geometry and selected the input
in the first command.  What happens if you remove the "-m 4" option?

> For some reason, pvr250-setchannel -m 4 196.25 (or some other frequency) fails some times. It goes like this; if I run the command with the frequency 196.25, it succeeds. I then change to another frequncy, which also succeds. But some times, it fails, and that might be on a frequency that was working just a minute ago.

AFAICT, whenever you set the frequency, the tuner resets itself, so it
doesn't matter whether that frequency was working previously.  As
usleepless suggested, it sounds like an AFC problem.  Maybe AFC isn't
working correctly?

> and after that I can use 'mplayer /dev/cxm0' (or gmplayer, if I want a gui).
> For some reason, mplayer fails sometimes, with "seek failed".

The seek fails because of some buffering problem between mplayer and the
device.  I've had a terrible time getting this to work.  Try this instead:

	cat /dev/cxm0 > somefile.mpg &
	mplayer somefile.mpg

and I'll bet your seek problems will disappear (until you seek past the end
of the stream, obviously).

> Also, the picture quality is very bad most of the time, with the occasional momentarily *totally* *crisp* picture.
> Lots of interference and a "blurry" picture.

This sounds like an AFC problem.  Try the setchannel with "-a on" and make
sure to do the cat & mplayer separately.

> Whether this has something to do with my cabling or with the PVR-350 itself, I cannot tell. But I don't see such bad quality on the recordings from my KnoppMyth backend, which is on the same cable via a T-junction split).

I've seen some bad Ts and cables, of varying lengths.  Generally these are
ghosting and fuzziness problems, and the tuner seems to detect the carrier
frequency.  If you have severe flickering and missing frames, that's more
indicative of a tuner-related problem, AFAIK.  Try swapping the two cables
on the downstream side of the T.

-- Rick C. Petty