[mythtv-users] Request for help making live TV useable

Mark Lord mythtv at rtr.ca
Sat Apr 23 15:33:31 UTC 2011

On 11-04-23 11:21 AM, Bob Shanteau wrote:
> "Normal VDPAU" has 2 match criteria, so I set "vdpaubuffersize=50" on 
> each, and everything looked OK during a quick check of an old episode of 
> 60 Minutes in HDTV.

HDTV in Canada and the USA uses MPEG2 encoding,
which does not use more than a tiny handful of buffers.

Setting "vdpaubuffersize=nn" to a custom (large) value is most
useful for h.264 content, particularly hi-resolution stuff.

I just checked here, and got my numbers wrong earlier.
So for the record, before I updated my source tree with the patches
to automatically set the Right Values(tm), here's what I used to use:

Zotac HD-ID11 Ion2:  Advanced 2X playback, with vdpaubuffersize=42.
Zotac GT240 fanless PCIe in Core2duo box:  Adv.2X, vdpaubuffersize=36.

Those settings seemed to handle anything I threw at them for playback,
and both boxes were identical in performance.

Except.. the Ion2 gets jerky when "high quality scaling" is also enabled,
whereas the more powerful box has no such issue.


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