[mythtv-users] latest recommendation for VDPAU PCI card

Brad Templeton brad+myth at templetons.com
Wed Nov 4 08:56:42 UTC 2009

I recently put in a 8400gs pci card.  While the part number says it is a G84, vdpau
test declares it to be a G98, even though my research did not show any G98 8400gs
PCI cards on the market.

Here's what I observed, with both the 185 and 190 nvidia drivers, and ubuntu karmic.

a) It does indeed offset all the CPU as everybody says, which is good.  The older
machine was able to handle it, but barely and was getting warm sometimes.

b) As also reported, there is stuttering when the OSD appears, and especially when
it fades.  It still stutters if you turn off fading, though of course not as much.
The suttering appears regardless of the deinterlacer, in fact it appears on 720p
content and on 480i content for which there is tons of deinterlacing power.

c) In spite of reports that the 8400gs should do temporal 2x on 1080i no problem
I notice some stuttering.  And the OSD stuttering is bad enough to be unwatchable.
So I am using bob 2x for now on 1080i, and advanced 2x on SD.  Frankly, the new
deinterlacers are not noticeably sharper than the software ones so I am not too
worried about this for now, but still debating getting a 9400 or 9500 which are
the only other units you can get in PCI.

d) I know the OSD stuttering is being worked on, but I do a lot of arrow key
manipulation, so at this point I would prefer to turn off OSD when I do the 30
second skip or 8 second backwards.  I would love an option to turn it off except
if I hit i, or to toggle whether it happens or not, at least until OSD under
vdpau is recoded as I know is planned.   Is there a way to do this?

e) The vdpau decoders are more sensative to damage in the video stream due to
firewire errors or OTA noise.   Quite a bit more in some cases -- I am not sure
what fix there is for this except to push nvidia to improve the drivers.

f) If you use vdpau with mplayer, you need to set the codec manually which is a bit

g) A PCI card is so low in bandwidth that you can't do mplayer without vdpau any
more, while AGP 8x could do it fine, you had better be committed to vdpau if you
put in a PCI card.

Note the very slow get and put bits (due to pci bus I presume) but good decoding
rates.  The number for temporal 2x (66 fields/s) says it should work but it is on
the edge so it may be worth doing another card.

Intel(R) Pentium(R) 4 CPU 3.00GHz
28:08 NVIDIA(0): NVIDIA GPU GeForce 8400 GS (G98) at PCI:3:0:0 (GPU-0)

VDPAU API version : 0
VDPAU implementation : NVIDIA VDPAU Driver Shared Library  190.42  Tue Oct 20 20:55:52 PDT 2009


MPEG DECODING (1920x1080): 74 frames/s
MPEG DECODING (1280x720): 166 frames/s
H264 DECODING (1920x1080): 60 frames/s
H264 DECODING (1280x720): 108 frames/s
VC1 DECODING (1440x1080): 75 frames/s

MIXER WEAVE (1920x1080): 201 frames/s
MIXER BOB (1920x1080): 313 fields/s
MIXER TEMPORAL (1920x1080): 66 fields/s
MIXER TEMPORAL + SKIP_CHROMA (1920x1080): 90 fields/s
MIXER TEMPORAL_SPATIAL (1920x1080): 24 fields/s
MIXER TEMPORAL_SPATIAL + SKIP_CHROMA (1920x1080): 26 fields/s

MIXER TEMPORAL_SPATIAL (720x576 video to 1920x1080 display): 95 fields/s

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