interlacing, progressive, svcd stuff

[ThePanda]

Hi, I'm starting to get pissed with all this interlacing and IVTC stuff, i guess because i either don't know what i am doing well enough or the tools aren't good enough.

now i've got this tv anime dvd which i am pretty sure is 30fps because the frames all look different from each other and whatnot, so it seems like i should just have to deinterlace it right? i tried using different types of deinterlacing but it seems like none of them do it right and i still get all these jagged lines. my first question is: shouldn't a deinterlacing filter be working on more than one frame by combining the even fields from one frame to the odd frames on the next? it seems like it is just using one frame, making it look jagged.

also, i will be getting a dvd player soon which can play svcds, so i was wondering, can you just leave the interlacing on the svcd as it is on the dvd and you won't notice it because it's played on a tv, or do you still have to do the deinterlacing? i normally encode with divx and don't use vcds.

[ThePanda]

Another question: Could I encode in divx with the interlacing, then play it with a tv-out card on a tv and it would look fine? for some reason it seems like it wouldn't look right because of resizing.

[Guest]

A pure interlaced 30fps clip has 60 fields per second. Each of those fields is from a different moment in time. A frame is made from two successive fields. That is why combing occurs. Combining two fields from different frames will not help but could make it worse. You'll either just make another frame with two successive fields, or depending on field order, you may make one with fields that are three fields apart. The only time combining fields from different frames arises is when you are matching up fields derived from progressive frames, because you are looking to reassemble the fields that came from the same temporal moment.

Deinterlacing is always a major bummer. The best you can do is to try to limit it to the moving areas. The clear diagonal lines you get in anime unfortunately bring out the worst, but there simply are no really viable alternatives. So it's not that the tools aren't good enough; it's that there is no really good way to convert 60 fields per second into 30 progressive frames per second.

[trbarry]

For pure video source on anime you might want to try the GreedyHMA filter, with:

GreedyHMA(1,0,0,0,1,0,0,0) or
GreedyHMA(0,0,0,0,1,0,0,0)

depending upon whether your clip is top field first. These will make a 30 fps clip. See www.trbarry.com/Readme_GreedyHMA.txt

- Tom

[trbarry]

Another question: Could I encode in divx with the interlacing, then play it with a tv-out card on a tv and it would look fine? for some reason it seems like it wouldn't look right because of resizing.


Nobody has tested that option much but I did add an option to SimpleResize to support this. See www.trbarry.com/ReadMe_SimpleResize.txt

It has an option to do InterlacedResize(w,h) without messing it up too bad if you are going to leave it interlaced. But I'm not sure what DivX will do with it.

Gee, my last 2 posts look like I'm starting to advertise. Whatever. ;)

- Tom