Bjørn Konestabo wrote:
It's nice to know I'm not the only one. Unfortunately I haven't had
much progress. I recently tried swapping the FX5200 for
the 6800GT I have in my desktop computer, but the TV-out on that one
behaved exactly like the FX5200 in every directly observable way.
I still can't get it to have proper 25Hz refresh.
I did however find out why only the bobdeint filter results in a
really smooth looking video. Despite my modeline which gives me
perfect mapping
between framebuffer lines and tv-out lines, I still get blending
between the fields. Setting the environment variable NO_XV=1 revealed
that
XV is to blame. I got perfect "field separation" after that. I'm
guessing the video overlay window is scaled somewhat. Luckilly I'm
able to
photograph the phenomenon using my digital camera set to 1/50th of a
second, and really see if fields are blended or not, so I don't have to
rely on my eyes only.
OpenGL still ensures sync, but not using XV gives a performance
penalty which leads to unacceptable skipping. I need to fix this video
overlay
scaling issue before the filter I wanted to make becomes useful. I
also need to get MythTV to build, but that's another issue.
Is the snapshot in SVN more Fedora Core 4 friendly, or should I stay
with the 0.81 source release?
I'm quoting myself alot here because I had a little accident with my
system clock and my last mail was sent in october. As far as I can tell,
xv scaling (which seems to involve some filtering no matter what I do)
is really bad. It will blend even and odd lines quite a bit, and I don't
know
enough about v4l to do anything about it, or to know if that's at all
possible.
I've createa a video clip with static with lines in odd and even fields
I can use to detect blending between fields, and it clearly shows
xv will blend even and odd lines. So much for interlaced playback.
Turning off xv gives no blending, but horrible performance.
mplayer however has a video output mode called "gl", which uses opengl
textures for playback. It doesn't appear to blend even and odd lines,
syncs perfectly to the refresh, and is very fast.
As I understand it, video overlay (Which I'm assuming is the culprit) is
only one of the ways xv may accelerate playback. Is there a way
of tricking mythtv to be more like "mplayer -vo gl" and less like
"mplayer -vo xv"?
I've also created another videoclip using a non-realtime version of my
filter, containing interlaced fields at 720x576 50fps where only one
field is updated at each 50Hz refresh, and with it I do get perfect
temporal and spatial resolution (when played with mplayer -vo gl) on my
system.
It plays with some frame drops, but I'm wagering a filter implementation
will be less stressful than decoding a 720x576 50fps xvid stream.
--
bjornko
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