Regarding Top Field or Bottom Field

[dinkob]

I found some threads in the forum that have this discussion but it seems there is no solution found yet as to what IS the final FIELD order on the encoded mpeg-2 - soon to be DVD.

Someone suggested that input avi should be put into Tmpgenc Wizard to do it's judging field order process.

However, in my experience it hasn't been right all the time (I have cut small portion and it was the opposite of what the big final mpeg was).

So it occurs to me that THE field order might depend on the length of the source file; most likely AVI.

In shorter captures less than 6 mins, in my recent encodes it tends to be almost always TOP field - field A, whereas above that it tends to be Bottom Field - field B.

It's not always TRUE, but in my case it LEANS toward that method. I always encode twice regardless (Thanks to that Copy Option In CCE Basic, best 60 bucks I ever spent).

If you were to take something that is OK with Bottom Field, cut out a small portion of it and try it again with Bottom Field - it could turn out to be wrong.

B.T.W has this been discussed some more in the case I missed it, couldn't find it?

[adam]

For interlaced sources, the mpeg2 can have top or bottom field first, it doesn't matter you just have to select the same field order as your source. Length of the avi should not have anything to do with field order. A capture card should always capture with the same field order unless it gives you the option of choosing field order. Anyway, it is very easy to judge field order in TMPGenc, and no not with the wizard.

Load your source and go to the advanced tab. Enable the deinterlace filter and double click on it. Set it to even/odd field (field) Now click on the slider and scroll through your movie frame by frame. If it jumps then your field order is incorrect. Go back to the advanced tab and change it. Check both ways to find which is smoothest, and then use that field order. Don't forget to disable the deinterlace filter when your done.

[lordsmurf]

I would use GSPOT, new version, personally.

[dinkob]

I had just tried that method in tmpgenc.

It looks good so far, however, when applied to the whole file it "stated" the opposite of what it was in CCE which I already completed.

In tmpgenc on quite a long capture it was top field (which denies what I said) and even when I cut out the file with "source range" option it was still showing top field.

CCE encoded mpeg-2 file that I played in my DVD player (again, smaller portion of the whole file) was the bottom field. (I always mark two files with added AF, and BF before the extension and burn them to DVD - hence I can be 100% sure that it was bottom field).

I guess I gotta keep doing it the way I did. Use that copy button and just change that output top field stream first box.

That way I know one out of two will be right for sure, while I have a cup of coffee or something.

EDIT: I tried downloading new GSpot and the site is down but I will check it when I can and if it's downloadable.

[SaSi]

Another way that may help identifying field order in the source AVI is the following:

load VirtualDUB, enable hw acceleration, load the avi, play it back.

Try the two options (Field A and Field B) for playback. One of them will give horrible picture. The best picture is given when selecting the correct field order.

Regarding the MPEG file, Restream can definetly give you a correct answer on how the file is encoded. (whether it was encoded with the correct field order is something else).

Your comment on field order being dependent on AVI length is interesting. I have made a couple of huge (8+hours) captures to AVI using MainConcept's capture feature. I extracted a part from the beginning and another from the 6 hours mark or so.

I noticed that the first one was TTF (as I had set it to be) but the second one was BFF. Noticed this after encoding to MPEG2, authoring and trying it on TV. Changing the Field order flag with restream of course corrected the problem.

My guess is that while capturing, a droped frame (or field???) can cause field order re-arrangement (of course this would be a bug) and after the dropped frame (or field) field order is changed. Obviously, in short captures dropped frames or fields are more unlikely. In long ones, anything can happen.

Just a guess.

[lordsmurf]

Interlace bugs usually end up with vertical jitter, not repairable.

[adam]

dinkob, make sure you realize how CCE works. CCE always assumes your footage is top field, and always creates top field footage. So if your footage is top field, the default settings are correct. If your footage is bottom field then you have to enable the top field first option. This then crops the first scan line changing your field order so that CCE can export top field first.

I think this may explain some, but probably not all, of these discrepancies. If it was encoded in CCE then it is NOT top field first any longer, no matter what your source was.

[dinkob]

dinkob, make sure you realize how CCE works. CCE always assumes your footage is top field, and always creates top field footage. So if your footage is top field, the default settings are correct. If your footage is bottom field then you have to enable the top field first option. This then crops the first scan line changing your field order so that CCE can export top field first.

I think this may explain some, but probably not all, of these discrepancies. If it was encoded in CCE then it is NOT top field first any longer, no matter what your source was.

AhA yes, thank you.

Sigh should have read that manual more precisely.

I'll think in reverse when I use CCE.

My guess is that while capturing, a droped frame (or field???) can cause field order re-arrangement (of course this would be a bug) and after the dropped frame (or field) field order is changed. Obviously, in short captures dropped frames or fields are more unlikely. In long ones, anything can happen.

Yeah had that issue too. Then I usually go about splitting the avi file or do the two cce encodes; up to that point and after that point.

[Phoebos]

ULead DVD Factory has a testing feature (deciding top or bottom field order) but is gives OPOSSITE result with TMPGEnc Plus!!!!!!?????

Which is true and which fault?

[lordsmurf]

ULead DVD Factory has a testing feature (deciding top or bottom field order) but is gives OPOSSITE result with TMPGEnc Plus!!!!!!?????

Which is true and which fault?

Ulead uses a backwards definition.

[TaranScorp]

Where in Gspot does it tell you what the fied order is?
I looked at the GUI for five minutes and could't figure out where

[lordsmurf]

Where in Gspot does it tell you what the fied order is?
I looked at the GUI for five minutes and could't figure out where

Use new version, says TFF or BFF (if IL) on the right side in video info. It may be PROG if progressive.

[TaranScorp]

I downloaded the latest release and all the little boxes in the video section are grayed out. I can see the letters for TFF,BFF and Prog, Inter but they are all grayed out.
I'm running Win2000

[BSR]

I toyed with it before and think the TFF and BFF only works with mpeg2 independent streams, not avi's(DV is what I tested).