[MPlayer-users] scaling and deinterlacing, telecine

[Carl Eugen Hoyos]

Matyas Sustik <mplayer.list <at> sustik.com> writes:

> 1. I read a comment saying that if you encode for TV then you may leave
> the movie interlaced.  What does it exactly mean to encode for TV?  I have
> a 1080p LCD HDTV which I am driving with a computer.  The refresh rate is
> 50Hz.  Does the above comment refer to my situation?  Should I prefer
> interlaced or noninterlaced videos (I can decide whether I deinterlace
> when I encode it so why would or wouldn't I do it?)

Your LCD screen is progressive, so you usually prefer de-interlaced
recordings. Note that I think you should only use a deinterlacer if the
material is actually interlaced (you can only find out this visually!), and
not telecined or whatever exists in NTSC country.

[...]

> 3. A film (24fps orig) was shown OTA in 1080i.  I cannot recognize the
> interlacing patterns for certain.  It looks like PPIIIIPPIIII which does
> not resemble any documented pattern I found.  I was so curious as to what
> the broadcaster did to this source that I asked it in email.  Here is
> what I got:
> 
> "Also, ALL programs on the HD channel are 1080i (interlaced).
> Programs that are not true HD are upconverted to 1080i with a high
> quality Snell and Wilcox upconverter."

If the original source was progressive (as most movies are), I don't think
what the upconverter produces is interlaced from your point of you (that is
what I see every day with SD MPEG2 via DVB. If somebody thinks upconverters
that are able to produce PAFF streams make a difference, please correct me).
If the original content was interlaced (like life broadcast often is), then
you will get much better quality (IMO) if you use a deinterlacer. yadif is
by far the best deinterlacer for MPlayer quality-wise.

Carl Eugen

PS: PPIIIIPPIIII reminds me a bit of the PAFF streams I tested so often: So
maybe what you see was really interlaced by the upconverter: Then I
recommend yadif.