[mythtv] New Video Decode and Presentation API

Daniel Kristjansson danielk at cuymedia.net
Wed Nov 19 01:24:31 UTC 2008


On Tue, 2008-11-18 at 19:42 -0500, Chase Douglas wrote:
> Does this API only allow for video processing output to a display  
> device? If so, does that mean it will not be useful for commercial  
> detection or even just rendering to individual frames for use in  
> commercial detection?

It looks like you can read back bits:
ftp://download.nvidia.com/XFree86/vdpau/doxygen/html/group___vdp_video_surface.html#ge3550dc62e4e4c390c1874b37f96e7c0

This is a good question. If the nvidia provided deinterlacers
aren't as nice as one might hope, it may be possible to read back
the data and feed it through the conventional software or OpenGL
deinterlacers. My hope is that built-in deints are sufficient,
I just got a 8300 in the mail today so I may be able to test that
theory soon...

Caveats:
 1/ This may be less efficient than doing the decoding in software,
    reading from video memory is not generally an optimized path.
 2/ I don't know if this call is actually supported by real hardware.
 3/ The commercial detector, transcoder, etc do not have access to
    the display hardware.
    a) There is no OS support in Linux for parcelling out GPU
       resources fairly so any implementation would be a hack.
    b) AFAIK no one is planning to implement GPU acceleration
       for any non-display connected utilities in MythTV.

-- Daniel




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