[mythtv-users] Consistent flicker with ivtv-fb + PVR-350 decoding

[Stefan Haflidason]

On 3/5/06, Stefan Haflidason <styrmis at googlemail.com> wrote:
>
> On 3/4/06, Stefan Haflidason <styrmis at googlemail.com> wrote:
> >
> > On 3/4/06, Al McIntosh < junkmail at allanmcintosh.com> wrote:
> > >
> > > Stefan Haflidason wrote:
> > >
> > > > On 3/4/06, *Al McIntosh* <junkmail at allanmcintosh.com
> > > > <mailto: junkmail at allanmcintosh.com >> wrote:
> > > >
> > > >     Stefán Hafliðason wrote:
> > > >
> > > >     >Hi all,
> > > >     >
> > > >     >I'm using mythtv 0.19 with a PVR-350. Recently, I think since I
> > > >     upgraded
> > > >     >to 0.19, I have been getting a constant flickering when
> > > watching
> > > >     live tv
> > > >     >through the tuner or s-video inputs. The flickering might be
> > > better
> > > >     >described as a fairly regular flash of black.
> > > >     >
> > > >     >I am also getting the following errors many times in
> > > >     /var/log/messages:
> > > >     >
> > > >     >ivtv0 warning: prep_user_dma: SG_length 400 page_count 400
> > > still
> > > >     full?
> > > >     >ivtv0-osd warning: ivtvfb_prep_dec_dma_to_device, Error with
> > > >     >get_user_pages: 1638400 bytes, 400 pages returned
> > > >     >ivtv0-osd warning: Error: prep osd dma to device rc=-5
> > > >     >ivtv0-osd warning: DMA xfer from b7318008 of 1638400 bytes
> > > failed
> > > >     with
> > > >     >(-5) offset = 0x0, total 1638400
> > > >     >
> > > >     >I am currently running:
> > > >     >
> > > >     >kernel 2.6.10-r9 (Gentoo),
> > > >     >PVR-350,
> > > >     >ivtv 0.4.2 - I have just tried 0.4.0, no difference
> > > >     >
> > > >     >The flickering only occurs when using the PVR-350's decoder to
> > > watch
> > > >     >something on either input (currently static on the tuner
> > > (limited
> > > >     access
> > > >     >to aerial) and tv-out from another computer on the s-video
> > > input).
> > > >     >Watching a previous recording (with no flicker) works fine.
> > > >     >
> > > >     >Thanks,
> > > >     >
> > > >     >Stefan.
> > > >     >
> > > >     >
> > > >     >
> > > >     >
> > > >     >
> > > >
> > > >     You may consider taking this topic over to ivtv mailing lists.
> > > >
> > > >
> > > > Will do; apologies for the mis-posting.
> > >
> > >
> > > I don't think apologies are required. Was thinking for your sake you
> > > may
> > > get better results. :)
> > > _______________________________________________
> > > mythtv-users mailing list
> > > mythtv-users at mythtv.org
> > > http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
> > >
> >
> > At the time it seemed like a very silly mistake to be blaming myth for
> > that problem. However, after seeing this thread on the ivtv-devel list (
> > http://www.gossamer-threads.com/lists/ivtv/devel/24487?page=last ) it
> > looks like I might be back here again soon :-) as they point the finger at
> > myth's use of overlays.
> >
> > From memory this problem did not occur with 0.18 (whereas in the linked
> > thread 0.18.1 was causing this problem for that person).
> >
> > Anyone else finding black flashes when using both the encoder and
> > decoder simultaneously on a 350 with 0.19?
> >
> >
> >
> Have there been any major changes to the way items such as the osd and the
> guide are rendered to the framebuffer when using the tv-out of a PVR-350?
>
> Regarding the flickering, it does not occur when running:
>
> dd if=/dev/video of=/dev/video16 bs=64k
>
> The picture is flicker-free, with no ivtv0-osd dma errors in dmesg. The
> only time that the flickering occurs is when viewing live tv on the tv-out
> of the 350.
>
> So, my question is really re-cast to: What does myth do differently when
> watching live tv on the tv out, compared to when it is simply sending a
> recording to the tv out (despite utilising the card's encoder). Are there
> any options I can play with?
>
> Failing that, are there any people who are successfully using a PVR 350
> with 0.19? If a couple such people could post here that would be helpful.
>
>
>
>
I found the source of the problem. On the 1st of March I enabled Appearance
-> Use GUI size for TV playback.

With this option on:

- Flickering.

With it off:

- Transition from menu to watching TV is jerky.
- The guide, when overlayed, is up and to the left (where the menu would be
without the offsetting) and so is partly off the screen.

If anyone has any tips on how to get the frontend to be in the right place,
and for the TV and guide to be in the right place I'd appreciate hearing
them. Otherwise, I'll get back to experimentation and hopefully work it out.
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