[mythtv-users] Mac Mini Video Acceleration Question (h.264)

Andrew Gallatin gallatin at cs.duke.edu
Sun Oct 11 01:49:13 UTC 2009


Scott D. Davilla [davilla at 4pi.com] wrote:
> 
> The Crystal HD handles mpeg2, h.264 and vc1 video decode. Performance 
<...>
> without having to transcode. The CPU is all display handling as the 
> decode is handled by the crystalhd.

Does this plug in at roughly the same place as VDPAU acceleration
would in MythTV (or XBMC)?  Or will it offload everything enough so
that MythTV can't screw up playback?

I'm asking because a few months ago I bought an Ion box intending to
switch to Mythtv away from a Sigma based SageTV frontend. But even
though VDPAU acceleration is in use, MythTV still manages to
incorrectly interpret the telecine flags in my local 1080i and 720p
broadcasts.  Any 24fps content looks terrible as soon as there is any
motion.  The same recording is silky smooth played on the Sigma based
SageTV HD100 (and in 7MC on the Ion).  When playing 24fps content,
MythTV is constantly complaining about the fps changing and the video
being ahead of the audio.  For example, here is a snippet of 0.22
playing back 24fps content broadcast in a 720p 60 signal:

2009-09-19 09:55:59.109 NVP(0): Video is 3.15555 frames ahead of audio,
			doubling video frame interval to slow down.
'video_output' mean = '20397.50', std. dev. = '7295.41', fps = '49.03'
'video_output' mean = '17741.75', std. dev. = '4277.02', fps = '56.36'
2009-09-19 09:56:03.614 NVP(0): 3200 progressive frames seen.
'video_output' mean = '18268.11', std. dev. = '5124.45', fps = '54.74'
2009-09-19 09:56:04.473 NVP(0): Video is 3.12797 frames ahead of audio,
			doubling video frame interval to slow down.
2009-09-19 09:56:04.510 NVP(0): Video is 3.45489 frames ahead of audio,
			doubling video frame interval to slow down.
2009-09-19 09:56:04.546 NVP(0): Video is 3.89486 frames ahead of audio,
			doubling video frame interval to slow down.
2009-09-19 09:56:04.583 NVP(0): Video is 4.19487 frames ahead of audio,
			doubling video frame interval to slow down.
2009-09-19 09:56:04.620 NVP(0): Video is 4.62968 frames ahead of audio,
			doubling video frame interval to slow down.
2009-09-19 09:56:04.657 NVP(0): Video is 4.88084 frames ahead of audio,
			doubling video frame interval to slow down.
2009-09-19 09:56:04.695 NVP(0): Video is 5.27903 frames ahead of audio,
			doubling video frame interval to slow down.
2009-09-19 09:56:04.732 NVP(0): Video is 5.5327 frames ahead of audio,
			doubling video frame interval to slow down.
2009-09-19 09:56:04.768 NVP(0): Video is 5.91776 frames ahead of audio,
			doubling video frame interval to slow down.
2009-09-19 09:56:04.805 NVP(0): Video is 6.1616 frames ahead of audio,
			doubling video frame interval to slow down.
2009-09-19 09:56:04.842 NVP(0): Video is 6.53929 frames ahead of audio,


I haven't found any linux based s/w player that will corectly handle
this content, so I'm hoping that a 100% hardware solution that's still
MythTV compatible will work.

Thanks,

Drew


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