[mythtv-users] VDPAU field report

Yeechang Lee ylee at pobox.com
Sat Jan 31 05:32:32 UTC 2009


An early report on VDPAU through Jean-Yves Avenard's patch for 0.21
follows. I am using the ATrpms 180.22 drivers and an Asus 8400GS with
512MB
(<URL:http://www.newegg.com/Product/Product.aspx?Item=N82E16814121235>
with my more than three years-old frontend running CentOS 5.2. I only
have MPEG-2 recordings from ATSC and FireWire, with the exception of a
few old MPEG-4 files from mythtranscode. Most of the tests were
conducted with a 1080i ATSC recording from CBS
(2051_20090125213600.mpg).

1. Playback with the Advanced 1x deinterlacer is perfect, with no skips
at all in the mythfrontend log output (except maybe during OSD fading)
(<URL:http://pastebin.com/f1e3299c6>); Advanced 2x exhibits the
occasional brief skip that's hardly visible in the actual
playback. CPU usage is 2-5%, with occasional jumps to
>10%. But . . .

The above holds only for the first playback. Once exiting, all
subsequent playbacks until telinit 3/rmmod nvidia/telinit 5 skip
continuously, regardless of Advanced/Temporal 1x/2x
(<URL:http://pastebin.com/d3303f5dd>). Bob 2x is relatively
OK. Switching between RTC and OpenGL vertical sync does not change
this behavior.

2. A more serious issue is that I can reliably hang the frontend by,
during playback, bringing up Program Finder, Program Guide, or
Upcoming Recordings. Ctrl-Alt-Backspace does not work and any SSH
session into the frontend hangs too. Magic SysRq does work,
fortunately.

3. A third, minor, peculiarity is that VDPAU output does not seem to
be affected by my specified gamma settings, whether in xorg.conf or in
nvidia-settings, so the video is far too dark for my tastes. I'm
probably missing something obvious here. Possibly related to this is
that the OSD font using VDPAU is much smaller than without. (Both the
gamma font issues correct themselves once I switch back to xv-blit
without restarting mythfrontend, so it's not that I accidentally
deleted xorg.conf or something.)

Because of issue 2, I've reverted to xv-blit output for the time
being. (One interesting change here is that with the 8400GS I must use
OpenGL vertical sync to avoid stutter with Bob; RTC does not suffice,
as it did with a 6200TC, or 7300LE [even with 180.22]. I hope I won't
run into the issue I describe at
<URL:http://www.gossamer-threads.com/lists/mythtv/users/366583#366583>.)

PS - I did make one change to Jean-Yves' patch, raising
MIN_OUTPUT_SURFACES to 6 and MAX_OUTPUT_SURFACES to 8 to see if that
helped with issues 2. It did not. The output logs are from
post-change.

-- 
Frontend:		P4 3.0GHz, 1.5TB software RAID 5 array
Backend:		Quad-core Xeon 1.6GHz, 6.6TB sw RAID 6
Video inputs:		Four high-definition over FireWire/OTA
Accessories:		47" 1080p LCD, 5.1 digital, and MX-600


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