[mythtv-users] VDPAU on older pre-G98 8400 GS

[Frank Merrill]

On Mon, Jan 4, 2010 at 8:59 PM, Eric Sharkey <eric at lisaneric.org> wrote:
> Is anyone successfully using VDPAU on the older 8400 GS cards?  I have
> one frontend with a newer G98 8400 GS and it seems to be working just
> fine with VDPAU, but on my main frontend/backend system it's got the
> G86 core and enabling VDPAU gives extremely stuttery playback with
> lots of audio dropouts, even with deinterlacing disabled.  The same
> recording plays acceptably with xv-blit.  (The other thing which is
> different is that the motherboard has only a PCI Express x4 slot, not
> an x16.)
>

The G86 core only supports feature set A, so, it really depends upon
what it is your trying to play.
What is the format of content?
Feature set A:  Complete acceleration for H.264, Partial acceleration
for MPEG-1, MPEG-2, VC-1/WMV9

A change to vdpaubuffersize may also help (or may not) depending upon
the content.
Output resolution may also be a factor.

As far as the PCIe X4 slot, that would still be ok as long as an x16
card can physically be inserted in it, as that is part of the PCIe
spec, to allow the card to use the available lanes.  The bandwidth on
an X4 slot is still better than on a PCI slot, so that isn't likely to
be an issue.

As a somewhat similar example, I actually have 2 8400GS cards with G98
cores, but they only have 256MB of memory.
Really not enough, but if I use it with a display that has an actual
pixel count of 1024x768, and no deinterlacing, it works fine.
Myth scales the content, and it actually looks very, very good on that
particular old 42" plasma.
I had to adjust the vdpaubuffersize down from the default of 17 to 12,
or else VDPAU would fail to play the content.
It plays 720p content just fine in MPEG2 or H264 (scaled of course).
I actually got two of those cards for $15 each on eBay (they were
advertised as having only 128MB, but they have 256).  They are great
for situations where the actual display has no more than 1024x768
pixels, and I have a few of those.
I think in testing I was able to take it up to 1152x864, but it was
pointless, since the display would have had to scale that down anyway.

Not sure any of that is any help, but good luck!

Frank