[MPlayer-users] Scaling interlaced video for DVD playback

Neil Radisch nradisch at panix.com
Fri Nov 14 12:28:15 CET 2003


> The resulting video is still interlaced, but with more thick lines, which
I
> think is ok given the rescale operation.

No it's not ok. The "thick lines" means you've altered the interlace and
it will not display properly.

In order to compress interlaced material you either have to use an encoder
that really understands interlace, or fake it.

As for the first option, I don't believe any of the opensource encoders
under linux truly support interlace, but I may be wrong here.

As for faking it, you might have to write your own compress app. I'm not
sure what mencoder's capabilities are as I've never use it. But regardless
you
either need to

1) Seperate out the fields. Take the source and seperate it into two fields.
Compress
    the fields independently. On playback, decode the fields then weave them
back together
    as a frame. You'll need to write your own compress and playback app for
this.
2) Fake the width. Someone (Billy Biggs?) suggested this to me. Feed the
interlaced frame
    into the decoder, but tell the decoder that the frame is twice as wide
and half as high as
    it really is. This stops the encoder from "smearing" the interlace and
screwing up the motion.

Neil




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