On Tue, Aug 23, 2011 at 1:53 PM, Roger Dahl <[email protected]> wrote:
> I have two cards, a PVR 250 and an HVR 1600. In my experience, both of these
> cards are easily confused by junk in the video signals during the vblank and
> overscan. It's just bad engineering because LCD TVs have no trouble at all
> with the signals. Issues I'm seeing are poor hsync at the top of the screen,
> misinterpreted odd/even field signals and poor colors.
>
> My guess is that the tapes you're having trouble with were recorded in some
> way that is causing the VCR to output junk during the vblank and/or overscan
> periods that cause the card to lose track of the vsync signal in the video.

For what it's worth, I've seen this sort of thing before in devices.
In most cases it can be fixed by poking the register that controls the
tolerances for vsync/hsync.  Most video decoder chips I have seen have
a "vcr mode", which when enabled widens the tolerances at the cost of
overall quality.

That said, I haven't dug very closely into the docs for the Conexant
video decoder core (known as the Mako) to see how to manipulate this
functionality.

And yes, it pretty much universally is the result of the VCR putting
out a crappy/malformed signal.

Devin

-- 
Devin J. Heitmueller - Kernel Labs
http://www.kernellabs.com

_______________________________________________
ivtv-users mailing list
[email protected]
http://ivtvdriver.org/mailman/listinfo/ivtv-users

Reply via email to