What really happens with "progressive"?

[MNale]

My source material is 720x486 29.97 NTSC interlaced . I use a Decomb avs script to IVTC...

Telecide(guide=1)
Decimate(cycle=5,mode=1,threshold=50)

I see no appreciable difference in the CCE generated mpeg2 file whether I check "progressive" or not. What is the effect of using (or not using) this option on my mpeg2 files that will be used for DVD?

[wmansir]

I have done a couple of test with progressive on and off and the only difference I could find (with SVCD) was when I paused, or used the step function on my DVD player.

The source was progressive (30fps deinterlaced), and visually the results looked exactly the same, with the exact same file size. However, if I paused the SVCD on my DVD player, the video that was not encoded with progressive checked would be displayed as flickering interlaced. So instead of getting one whole frame when paused it would display the odd field from one frame and the even field from the next. This effect continued when stepping thru the frames.

When Progressive was checked in CCE the disc paused fine.

I'm sure someone here can give an exact technical answer, but as far as I can figure out it is just a flag set in the stream, and it doesn't change how CCE encodes the video.

[new_age]

Hello!

Mpeg format can be interlaced or non interlaced (in other word: progressive) so if you want to encode an interlaced source you've two choices:

1) somehow deinterlace and create a progressive mpeg file (it can be an interlaced [non progressive] also but you won't see any diff)

2) encode the interlaced source as an interlaced mpeg (non progressive) and you save a lot of time because there is no need for deinterlacing.

NA

[MNale]

Thanks for the reply... you say "encode the interlaced source as an interlaced mpeg (non progressive) and you save a lot of time because there is no need for deinterlacing".

When I do this method (CCE / MPEG2 / Non Progressive), I still see some interlace artifacts (mouse teeth / horizontal jaggies) on my NTSC monitor. Granted, it's not as bad as on a progressive scan monitor, but they are still there. When I play back the interlaced source file on NTSC, it looks fine, but the encoded MPEG2 has the artifacts. Any idea on how to eliminate this?

[new_age]

It is interesting that you see theese interlaced artifacts. If an mpeg file (mpeg1, mpeg2) is interlaced the software or the hardware player must do some kind of deinterlacing. (on tv you do not need any deinterlacing)

So what kind of mpeg player do you use? Most software based mpeg player uses a simple blend fields method I guess.

My opinion is that the real benefit of the interlaced mpeg files is watching them on tv.

NA

[Faceman101]

Progessive should only be checked if your source is progressive (while I wish that button would just make my source progressive). I think the problem you are having now has to do with your AVS script. I noticed while using that same method the same thing on my DV footage (would guess that is what you are using). Instead of using deinterlacing, I just left the footage interlaced. Try not deinterlacing, leave "top field" button selected and if your footage shows interlace lines or jerkiness in motion try Pulldown to reservse the fields.

Interlacing material should be encoded with the interlace intact b.c of like earily mentioned, you lose quality. But then you run into problems. IMO TMPGEnc does a much better job encoding interlace material than CCE (in most cases, in some it doesn't matter).

Interlacing causes more problems than it solves in new technology. Personally I hope everything goes progressive.

[MNale]

Thanks for the reply. I have since sorted out a field order problem and testing criteria (mpeg-2 on cd vs. mpeg-2 on dvd) and now have a nicely interlaced DVD playback (I am no longer using Decomb).
I wonder what the source material is for professional dvd production? I doubt that it is telecined film-to-tape transfers which would have inherent IVTC and 3:2 problems when encoding to a progressive MPEG-2. I have yet to find a way to do a reliable IVTC (or deinterlace process) that will create an acceptable progressive MPEG-2 stream, so I guess I'll have to stay interlaced and wonder how the pros do it.

[auenf]

Film (24fps) -> MPEG-2

Enf...