[MPlayer-users] vsync and nvidia (was: [BUG] -vf tfields=4 jumpiness -- OSD flickers madly)

[Jason Tackaberry]

On Mon, 2003-11-03 at 23:13, D Richard Felker III wrote:
> My first hint is to make absolutely sure that no scaling is going on.
> Your video mode MUST be 480-lines (so 640x480 would be a good choice)
> or you'll trash the interlacing. Also, the tvout needs to be on the
> primary head, or you'll get tearing, which will be extremely bad with
> interlacing. If you fix these two things, I think it should work
> great.

The TV is in fact the only device connected to the video card.  There's
no monitor.  I'm very satisfied with output from all my DVD rips. 
Scenes with heavy panning are quite smooth.  My complaint so far is just
with the interlaced material I'm pulling from the TV capture card.

I was running at 800x600, so I set the display to 640x480.  I was also
capturing at 720x480 which mplayer was scaling to 720x540, so I changed
the capture to 640x480 as well. I've also tried 16- and 24-bit. 
Unfortunately it hasn't improved.  With CNN's marquee, the letters are
still jagged as they scroll.  Also, many live programs like talk shows
feel a little sluggish (i.e. their motion doesn't seem natural, at least
as compared to the way they appear when I view the feed directly on my
tv).  I might be explaining this poorly. :)

One thing that may be affecting things is the overscan.  Nvidia's driver
has an overscan option.  I've tried settings between 0.0 and 1.0
(including not specifying at all) and it doesn't completely solve the
problem, however I'm noticing that the "magic disappearance of jaggies"
on the marquee text is more likely to occur for a while when using an
overscan of 0.9.  

It might be relevant to note that I'm able to affect things by
pausing/unpausing the video.  If the text is jagged, pausing/unpausing
the video a few times often will correct that.  Likewise, if it looks
okay, pausing/unpausing once is usually enough to revert the scrolling
text into ugliness. :)  Of course, I guess that's not so surprising if
the problem is vsync.

As I understand things, my TV capture card will output a 29.97fps
interlaced mpeg2, and when I play this back, the video card ought to
split each frame into two fields.  The process _should_ be lossless (at
least as far as frame rate is concerned), so I've got to be missing some
crucial element.

Cheers,
Jason.