[pvrusb2] HVR-1950 - bad video quality

[stan schultz]

So,  Let's back up a bit..  Remember, I can get WinTV to provide good
reception.  That implies that the WinTV guys are setting at least one
parameter on the card differently than pvrusb2.  So,  If that's the case,
can I initialize the device with wintv and then plug it in to the linux box
and not have the parameters mucked with?  Then I can read them with the
/sys/classes interface and see what's different.  Will that work, or does
the driver initialize everything when the device is plugged in?

Stan

On Thu, Apr 2, 2009 at 11:13 PM, Mike Isely <isely at isely.net> wrote:

> On Thu, 2 Apr 2009, stan schultz wrote:
>
> > So I got the camcorder out, plugged it into the composit input and the
> > picture from it looks great.  As you said, that points at the tuner.  A
> > couple searches showed there is all kinds of discussion about bad uscable
> > table entries in mythtv. But I couldn't find anything truely useful.  I
> > tried modifying the values in
> /sys/class/pvrusb2/*/ctl_frequency/cur_value,
> > but didn't really see a positive difference ever.
> >
> > Any Ideas?
>
> Well I only do over-the-air here, no cable, so I don't have a good basis
> for comparison with your situation.  So I don't know how good / bad
> MythTV is going to be when tuning cable.  Obviously the pvrusb2 driver &
> hardware is not going to "care" where the signal is coming from so long
> as the signal is coded following the standard it is configured for and
> that it knows the right center frequency to tune for it.
>
> In your shoes I might consider trying something that can instead
> directly scan all the possible frequencies itself.  I think a long time
> ago I did this once with xawtv - the scantv part of the app IIRC can be
> told to creep through the frequency spectrum with very small increments,
> much higher granualarity than what would normally be required.  This
> might allow you to have a fighting chance at least to figure out the
> right frequencies.
>
> If the issue is not so much the correct frequency table but just finding
> the right channels in the table, then you should try an app that can
> simply do a scan.  Again, xawtv can do this.  (And so can MythTV.)  If
> you try xawtv, please be aware of its caveats - the largest of which is
> that I don't think it's in active development anymore.  The pvrusb2
> driver's usage web page has additional important details about setting
> up and using xawtv:
>
> http://www.isely.net/pvrusb2/usage.html#V4L
>
> Obviously you still want to use MythTV, but if you can get another app
> to tune the hardware properly then you can at least rest assured that
> the hardware and the driver are correct - then you can focus your
> attention on getting MythTV to behave correctly.
>
> Here's another wild idea:
>
> http://home.arcor.de/saedelaere/index_eng.html
>
> I'm not sure if Christian (the author) is going to suddenly want a huge
> pile of attention, but he's been talking to me about this app he's been
> writing.  It's called "TV-Viewer".  Essentially it's a nice looking gui
> that builds a TV app out of other building blocks.  I tried his 0.8b1
> version a few days ago and it looks very slick.  I only mention it here
> because it's capable of doing a channel scan.  You might want to give it
> a spin...
>
>  -Mike
>
>
> --
>
> Mike Isely
> isely @ pobox (dot) com
> PGP: 03 54 43 4D 75 E5 CC 92 71 16 01 E2 B5 F5 C1 E8
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