deinterlace

[grokwik]

When making dvd back up ( dvd9 to dvd r) with dvdrebuilder for example, I don't understand the interest in deinterlacing the movie (even if the movie is interlaced) because the dvd is to be seen on tv.... is there a good reason ?

[killingspree]

in most cases not... only reason i can think of is, if you want to display it on some kind of progressive display that doesn't like interlaced material (e.g. my beamer doesn't like interlacing at all - it completely blurs the picture, etc)

apart from that i do not think it will increase your resulting quality, so for the average user this option isn't really relevant!

kr
steVe

[grokwik]

thank you very much. So I've made the good choice in dvdrebuilder..

[influenza]

Interlaced material requires a lot more bitrate than progressive material. So for that reason you could deinterlace to make it progressive. This is useful if you're going to encode at low bitrates (eg. extras).

Besides that there is the fieldorder, which is important on interlaced video and doesn't matter on progressive video. SO deinterlacing will prevent you from getting that kind of problems (stuttery playback).

There's a tradeoff of course. If you deinterlace you'll ruin motion (or at least that's the common opinion), if you keep the video interlaced and encode at a low bitrate you'll probably get blocks.
For this reason I usually keep the extras interlaced, but encode them at half d1.

on a sidenote:
Most PAL dvd mainmovies are reported being interlaced by bitrate viewers, but are progressive. ALmost al PAL dvds have progressive main video and interlaced extras. Exceptions are TV series and concerts which sometimes have interlaced main video.

[grokwik]

Thank you for these advices !

Most PAL dvd mainmovies are reported being interlaced by bitrate viewers, but are progressive. ALmost al PAL dvds have progressive main video and interlaced extras. Exceptions are TV series and concerts which sometimes have interlaced main video.

This is interesting, I have noticed that in my last back ups : all were reported interlaced but were progressive in fact. I don't know about the extra : I'll verify.