Hi, I have a question on interlacing. i'm ripping a dvd useing dvd2avi converter. and i'm wondering if the output is interlaced non-interlaced. or what the field order is,upper or lower. I'm going to eventually convert it back to dvd useing canopus. and that program askes if the avi is upper lower or field, or non-interlaced. is there tool that will tell me these things? Thanx.
Hello friend,
Well, AVIs don't have these traits - they are not NTSC or PAL, and they make no concession for being converted to DVD.
Film is 24FPS.
In the world of NTSC (Canada/USA/Japan/others) DVDs are 30FPS.
Your source (DVD) could be 24FPS, 30FPS (telecine) or 30FPS (true interlace).
Most times, when backing-up DVD to AVI (I use GordianKnot) the AVI is actually superior to the DVD because it is 24FPS, Progressive, no BS. It is film and has been 'restored' to its native state, y'know?
However, while ~90% of sources will be 24FPS film, there are some telecined (converted to 30FPS via 'invented' frames; these may be restored to 24FPS with IVTC) but some that are Native NTSC 30FPS interlaced. These are truly 30FPS, and are encoded to AVI @30FPS, with only the application of a de-interlacing filter.
The big challenge for NTSC rippers is identifying the 3 types of source!
If you convert DVD to AVI, and then try to transcode to DVD again, that's not good plan (AVIs are 'lossy'). It's like making orange juice from powder, or CompactDisc from MP3...
You will not get DVD back - you will have all the quality of the small filesize, but the large filesize of DVD. (Lose-lose scenario).
Quote:program askes if the AVI is upper lower or field, or non-interlaced
Well only the person who made the AVI knows what the source was, and maybe they converted inappropriately...
But, s'pose I downloaded an AVI, I dunno anything about it or its source; it plays okay (audio is in synch :^) and I don't care, I want to make DVD for broad playback compatibility.
Canopus asks these questions, you must answer!
If your AVI is 24FPS answer non-interlaced. This covers any 24FPS, whether source was Progressive (film) or IVTC (film, repaired).
IF you have 30FPS NTSC true-interlaced (rare), I can ID this when making the AVI using GKnot, so:
If you have a 30FPS AVI, you must trust that the person making it knew what they were doing, and it really is 30FPS NTSC.
In this case (rare) it doesn't really matter; WTF tell it 'upper' field first - this is kinda default, and Canopus should work okay with it...
If it mucks up, I dunno, try 'lower' first - the point is, this is unusual; most AVIs will be (should be) 24FPS.
If you wish to learn more about this stuff visit Doom9.org
(thank gawd for The Doomer) you will learn more than you wanted!
It is somewhat complex, but I have given you good advice,
Hope this helps, let us know :^)
Regards
