[MPlayer-users] Confused about deinterlacing and scaling

[Jason Tackaberry]

On Wed, 2004-07-28 at 00:36 -0700, * wrote:
> Hello, I'm about to spend 14+ days encoding some DVDs of television
> shows and it would be *fantastic* if someone could glance at my
> options and point out anything wrong (from past history I'm positive
> I must be doing at least a couple things wrong).

There are docs about this.  An encoding guide:

   http://www.mplayerhq.hu/DOCS/HTML/en/menc-feat-dvd-mpeg4.html

And dealing with pulldown and interlacing is a prerequisite:

   http://www.mplayerhq.hu/DOCS/HTML/en/menc-feat-telecine.html


> In particular I'm confused about the pp to use for deinterlacing.
> It sounds like pp=lb is best in theory but I have to say that pp=ci
> looks a lot less blurry.

The "best" deinterlacer is a topic for heated discussion, I've found. :)
Each deinterlacer artifacts in different ways, and the "best" one seems
to be more a matter of perception.  pp=lb creates ghosting, but I tend
to prefer it over the others.  I think most people agree however that
you should avoid pp=fd.

The best results I have seen are from bob deinterlacing but MPlayer
doesn't have this feature.

One option you have is not to deinterlace at all.  ffmpeg supports
interlaced video.  If you're encoding DVDs with a mixture of interlaced
and progressive or telecined video, this might end up being the best
option because the only other choice is to deinterlace the whole thing,
which really lowers the quality if a lot of it is progressive.  (Of
course, if there is no interlacing and only telecine/progressive, you
should use pullup.)

> Also I'm not clear on whether (or how) to scale after deinterlacing
> and cropping.

This is discussed in the encoding guide.  If you're deinterlacing first,
then you can scale or crop so long as your dimensions are multiples of
2.  The end result should have dimensions divisible by 16.  If you're
cropping first and the video is interlaced, make sure your vertical
dimension is a multiple of 4.

Cheers,
Jason.

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