Why should one deinterlace?

[Twin]

Ok, search function is currently being down so I start a thread instead.
So, why should one deinterlace?
Will the picture be better? Will the filesize grow? Does it require higher bitrate stay at the same quality?
Please help me out here =P

[Twin]

And what is the best way to deinterlace if you use DVD2SVCD (PAL)
?

[poopyhead]

de-interlacing will actually make the movie worse (by a little bit...i can't tel myself..but i'm pretty sure it gets worse quality)

however, you de-interlace when you used FORCED FILM in dvd2avi, yet your dvd rip has horizontal lines in it...de-interlace feature gets rid of these...at a price of course (slightly lower quality)

[kinneera]

It depends on the source. If you have a film source, it is preferable to perform an inverse telecine or use force film in DVD2AVI as the movie was originally filmed with progressive frames.

For broadcast and camcorder sources, you may need to deinterlace if you want to encode to MPEG1 (which doesn't support interlacing) or if you have some other reason for needing progressive frames.

[SatStorm]

First of all, my knowledge is limited to Pal.

With earlier versions of TMPGenc, de-interlacing helped in general. With the current versions, you don't need that.

In general, De-Interlace helps with standard VCD creation.
VCD is 352 X 288, progressive. If you capture a VHS tape with 352 X 576 resolution (ideal) or 704 (720) X 576 resolution (most cards support this resolution), then your source is interlace, with a few odd/even fields missing, depending the contition of your VHS tape. The encoder creates new frames from the combination of those fields. For VCD, which is 352 X 288 (240) resolution, you get in general better results if you de-interlace a source of that type. The encoder encode one field, and when a field is missing, it use it pair (odd or field, doesn't matter).
Field missing has nothing to do with Frame Drops during capturing . It is a different thing!

For DV most of the times you don't need to do de-interlace. Only on extreme situations, related with the bad contition of the DV source.
For DVD I found it useless, but other users may have different opinion.

With mpeg 2 at any resolution/format, you don't have to do interlace anymore.

[poopyhead]

wut i meant guys, was that for a DVD source that's FILM, progressive one would use FORCED FILM in dvd2avi..

however, because not all DVD sources are 100% FILM (i.e. maybe 95% FILM, 5% NTSC) there are still little bit NTSC, interlaced in the source..

however, because 95% FILM is close enough to 100% FILM, that we can treat the source as pure FILM and use FORCED FILM in dvd2avi...however, that 5% NTSC comes back to haunt you with some interlaced, horizontal lines after encoding with tmpgenc. this is where deinterlace comes in. it removes those lines (blend (adaptive) or double (adaptive)) is the best deinterlace option to use IMHO.