[mythtv-users] VDPAU CreateOutputSurface error

[David Watkins]

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
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