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

[Stefan Haflidason]

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.
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