[mythtv-users] black screen during playback

HP-mini blm-ubunet at slingshot.co.nz
Sat Jan 26 01:31:12 UTC 2013


On Fri, 2013-01-25 at 17:03 -0500, Joey Morris wrote:
> Joey Morris <rjmorris at nc.rr.com> wrote on Thu, Aug 23, 2012 at 10:27:30PM -0400:
> > Joey Morris <rjmorris at nc.rr.com> wrote on Wed, Aug 22, 2012 at 09:40:15PM -0400:
> > > I recently upgraded a combined backend/frontend and two frontends from
> > > 0.24 to 0.25.2. Several months ago, while I was on 0.24, one of my
> > > frontends suddenly stopped displaying video when using a VDPAU
> > > profile, instead giving me just audio with a black screen. It worked
> > > fine once I switched to a CPU-only profile. I mentioned it in
> > > http://www.gossamer-threads.com/lists/mythtv/users/514994, but I never
> > > resolved the problem, so I just stuck with the CPU-only profile.
> > > 
> > > I hoped the problem would resolve itself in 0.25.2, but it's actually
> > > worse. Now I get audio but no video even on the CPU-only profile. I
> > > tried VDPAU Normal, one of the OpenGL profiles, and Slim. All produce
> > > audio and a black screen. One difference is that the OSD is displayed
> > > when using VDPAU Normal but not when using Slim (I don't remember what
> > > happened with OpenGL.) The video plays fine in VLC.
> > > 
> > > I've tried the following with no changes:
> > >   - swapped in a different video card
> > >   - connected via VGA instead of HDMI
> > >   - copied the file to the local drive, added it to the video gallery,
> > >     and played it from there
> > > 
> > > I captured logs with -v playback while using the VDPAU Normal profile
> > > and the Slim profile. I would be very grateful if someone could review
> > > these to see if anything looks amiss. I'm happy to provide other
> > > information or logs if needed.
> > > 
> > >   VDPAU Normal: http://pastebin.com/KvZE1bZY
> > >   Slim: http://pastebin.com/r7hzd5G3
> > > 
> > > I also captured the log on my working frontend running the VDPAU
> > > Normal profile and compared it to the one above. The only difference
> > > that seemed like it might be significant is the lack of "Video is
> > > d.ddddd frames behind audio" messages on the working machine, so I'm
> > > not optimistic that these logs I've posted will reveal the problem.
> > > 
> > > This is on Mythbuntu 11.04 with an NVidia 210 card.
> > 
> > Tonight I tried using the onboard graphics instead of the 210 card. My
> > CPU is the i3-540, which is a Clarkdale. This time I did get video
> > using the Slim (and Normal) profile. I didn't get video using the
> > OpenGL Normal profile, however.
> > 
> > At least I have one usable configuration now, but I'd really rather
> > have VDPAU working. Does anyone have any ideas?
> > 
> > Since both of my 210s work on my other frontend and neither work on
> > this one, I don't think the card is to blame. I'm beginning to suspect
> > it might be a motherboard problem. But before I start buying new
> > hardware, I think I'll first see if I can get VAAPI going on this
> > system. Maybe that will be good enough that I can live without VDPAU.
> > If not, I'll try a reinstall from scratch.
> 
> I'm responding to this rather old email to report that I finally
> solved the problem, in case it helps someone searching the archives in
> the future.
> 
> I tried everything I could think of to isolate the problem:
> systematically swapping out every piece of hardware in the system,
> reinstalling the OS, upgrading Myth to 0.26, and deleting the playback
> profiles so Myth would regenerate the default ones. I still had the
> problem of the black screen during video playback using VDPAU. Nothing
> in the logs pointed to a problem.
> 
> Finally it occurred to me that a common denominator between all these
> configurations was the hostname, which Myth uses to pull in settings
> from the database. I gave the system a new hostname, and my video with
> VDPAU returned! I have no idea which setting in the database was
> causing the problem.
> 
> The lesson for me in this exercise was that to get a truly clean slate
> with a Mythfrontend re-install, you have to use a new hostname.
> Otherwise you'll pick up all the settings from your previous install.
> _______________________________________________

In recent months there have been at least 3 reports of the same symptoms
& solution on ubuntu forums (mythbuntu).
The difference is all 3 users were/are using ION IGP/chipsets.

There must be some residual dB settings not cleaned out by upgrade.





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