[mythtv] Interlaced vs. Progressive
david.asher at caviumnetworks.com
Sun Feb 26 05:14:01 UTC 2006
I've been following the development of the Internal video player closely
because I'd love to punt xine for displaying MythVideo stuff -- esp.
with the advent of DVD menu support.
But every time I've used it on an .avi (or DVD .iso), the picture
quality has been terrible. I never bothered to look into why until
today. It turns out that it appears to be entirely attributable to the
internal player thinking progressive video is interlaced -- and applying
the deinterlacer to it. If I disable the deinterlace in TV playback
options the quality is quite good.
It appears the "culprit" is detectInterlace which simply says (for non
720 video) if the fps is <= 45 it must be interlaced. These videos all
report ~23.97fps (DVD reports 29.997fps). Of course there is the
following comment too:
// The scanning mode should be decoded from the stream, but if it
// isn't, we have to guess.
So, obviously, I need to figure out why progressive/interlaced isn't
being "decoded from the stream".
I'm happy to look into coding an improved interlace detector -- but
don't have the slightest idea where to start. Anybody willing to point
me in the right direction? Other players which do it better learn
from? I suppose I could resort to adding a key to toggle deinterlace
from the player... That's pretty icky, though.
More information about the mythtv-dev