[pvrusb2] HVR1900 noisy video

[Martin MAURER]

Hi Mike,

thanks for the information so far.

If I can do anything to help to debug this, just tell me. I am software
developer myself, but I don't have any knowledge about this topic.

My personal first priority would be to find a workaround to reliably
initialize the tuner correctly during startup. Currently I do:
- tune to an analog frequency
- record 5 seconds
- run a dvb scan

Yet I still get the problem with videos recorded afterwards. When I do a
dvb scan manually afterwards it somehow fixes itself. I have no idea why
the automatic approach of doing the scan would make any difference. (I
pipe the output to a file during startup, so I am definitely sure that
the dvb scan is done)

regards,
Martin

On Sun, 2011-01-23 at 20:28 -0600, Mike Isely wrote:
> On Sat, 22 Jan 2011, Martin MAURER wrote:
> 
> > Hi,
> > 
> > Investigating a little further I found that it sometimes gets better
> > when I call "/usr/bin/scan at-official" (doing an dvb scan).
> > For some reason the analog video is then perfectly fine. I will check if
> > it remains fine, but first tests show that it does.
> > 
> > Anyways, adding this to my startup script didn't help for some strange
> > reason (and yes, I checked that is executed correctly)
> > 
> > regards,
> > Martin
> 
> Martin:
> 
> In *theory* doing something to the DVB side should not affect the 
> quality of the analog side.  In reality however, the two sides share the 
> RF tuner, which might suggest that the analog side of the V4L-DVB driver 
> for that RF tuner might not be setting up the chip properly.  The 
> pvrusb2 driver, being a "bridge" driver in V4L-DVB terminology, 
> delegates handling of a lot of the hardware to other drivers within 
> the V4L-DVB subsystem.  I'd suspect a misbehavior in the tuner's driver.  
> Making matters worse however is that Hauppauge has a habit of swapping 
> out tuner sections within different manufacturing runs of the same 
> device.  So reproducing this doesn't just require another HVR-1900, but 
> an HVR-1900 with the same tuner in it...
> 
> Unfortunately I don't have any HVR-1900 to test against (I'm in the 
> USA).  So I'm kind of stuck here.
> 
> Can anyone else here with an HVR-1900 (especially if you are using PAL) 
> reproduce this behavior?
> 
>   -Mike
> 

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