[mythtv-users] VDPAU CreateOutputSurface error

[Stephen Worthington]

On Thu, 20 Aug 2020 11:23:39 +0100, you wrote:

>Dear All,
>
>After a hard disk failure I'm trying to rebuild a frontend/backend on an
>old Zotac Ion motherboard.
>
>It had been running Mythtv V25 and Fedora 16 on 2GB RAM with no problem,
>making multiple HD recordings from DVB-T while playing HD at the same time.
>
>I installed lubuntu 20.04 over the weekend and Mythtv 31 from the repo
>which instantly revealed that 2GB RAM no longer cut the mustard.  (100% of
>CPU dedicated to kswapd)
>
>I scrounged 2x2GB of RAM and with 4GB I no longer see any swapping with
>reasonable CPU and Memory loadings shown by 'top' .
>
>In fact after a couple of hours things were looking good.  I  had
>recording and nice smooth HD video playback -  albeit without sound
>because I hadn't configured that yet.
>
>I ran the frontend setup wizard, got sound working and both video test
>samples (SD and HD) played fine with sound and picture.
>
>However, after exiting the setup wizard my recordings don't play anymore.
>They play with sound but a black screen.
>
>Interestingly, cancelling the playback and immediately starting it again
>sometimes produced the video, which then played perfectly with the sound.
>(CPU at about 70%)
>
>Playback log from a failed startup is attached.  Lines of interest appear
>to be:
>
>*...*
>
>*E CoreContext decoders/mythvdpauhelper.cpp:381 (CreateOutputSurface)
>VDPAUHelp: Error at decoders/mythvdpauhelper.cpp:381 (#25, A catch-all
>error, used when no other error code applies.)*
>.....
>
>*E CoreContext opengl/mythvdpauinterop.cpp:196 (InitVDPAU) VDPAUInterop:
>Failed to register VdpOutputSurface. Will retry.*
>
>*E CoreContext decoders/mythvdpauhelper.cpp:474 (MixerRender) VDPAUHelp:
>Error at decoders/mythvdpauhelper.cpp:474 (#3, An invalid handle value was
>provided.)*
>...
>
>zotac ion with 4GB Ram
>LUbuntu 20.04
>MythTV v31 from repo
>nVidia driver 340.108
>Playback profile vdpau with both deinterlacers at basic.
>
>I've since tried LUBUNTU 18.04 with Mythtv v29 (compiled by me) which
>suffers from the same problem in the log although this time the video
>either plays with sound and video or it just immediately bounces back to
>the frontend.  (Note the success:fail ratio is about 1:40)
>
>I've attached the playback log and if anyone can see anything useful in
>there I'd be grateful.
>
>Also, if anyone is successfully running a frontend on similar hardware
>please can you tell me your configuration  (OS version, Myth version,
>nVidia driver, setup tweaks etc...)
>
>I realise I can't assume 10 year old hardware will work but this doesn't
>quite feel like a hardware issue - and I don't want to throw the board away
>unless I have to.  It's tantalising that occasionally it does work!
>
>I'm running out of ideas though.  I'm thinking to try:
> - a different distro
> - a 32 bit OS (I think I was running 32-bits before)
> - a different nVidia driver version.
>
>I do have a suspicion that the sound setup might be causing the problem.
>As I said, while I was setting up my tuner cards and channels I hadn't
>configured a sound device, and I didn't notice any playback issues then.
>It was only when I got audio playback working that the problems appeared
>(The ion sound driver is nVidia too). This could all be coincidence of
>course and I don't know how to investigate further anyway.
>
>Any help very welcome
>
>Regards,
>
>D

MythTV v31 has new rendering code, so you may need to adjust your
settings for that to work well.  Take a look at the release notes.

I am still on v30, so I am not familiar with what the log output for
playing a v31 recording looks like.  But the thing that struck me in
your log was that it did not seem to be using VDPAU to render the
recordings.  Instead it seems to be using opengl-hw.  Maybe it would
work better if VDPAU was doing the rendering also, so it was offloaded
onto the GPU.