Field order.. A or B?

[X-treme]

I've read a couple threads where some guys state that when you load your movie in TMPGenc, the field order will be automatically selected (from what the source is); however, after reading more into it, people have stated that trying top field (A) over bottom field (B) will cause choppy/distorted picture when viewing.

I have tried BOTH field order's on the same I have, and I notice NO difference. Should I? People have stated that if the wrong field order is used I will see lines across the screen?

I'm currently encoding the video with the automatic field order that was set (Top field A).

I don't want to have to REDO this entire movie, so any info would be great!

Which is suppose to be used?!

Thanks

[guns1inger]

For PAL DV (and I assume NTSC DV, but who knows with NTSC) it is lower (B) field first. The easiest way to test - select a short (2 minute) scene. Encode one as upper (A) first, and one as lower (B) first. Burn them both to a DVD +/- RW and watch them. Make sure you pick a scene with a bit of motion it.

[lgh529]

It depends on what the source is. If the source is Top field first, then thats what you should encode at, and vice versa. DV is generally Bottom Field first, so thats what I encode with since 95% of what I do is DV related.

It probably wont' make much difference until you have an action scene, a crossfade, or some other faster motion clip, then you will see how terrible it is to get wrong.

[mazinz]

a long time ago someone posted an easy tip on how to figure out if the material you have is top or bottom source. It went like this--

open tmpg, input your clip, etc.

1. click setting, and go to the advanced tab
2. select what field order you want top/bottom
3. on the filters below select the deinterlace filter
4. once on this make sure enable filter is checked
5. next select the filter "even-odd field (field adpation)"

6. now hit the scroll bar and watch the clip. if you selected the top field (step 2) and the picture looks fine, chances are you have the correct field. If the picture plays somewhat broken/choppy change the field and try it again. One of the fields will play fine while the other is choppy. Whichever plays fine is the field your clip is

[X-treme]

I still haven't found the difference.

I used both top and bottom field with the same movie, and I do NOT notice any difference. If there is any choppy sections, I notice them at the same parts and same time.


Mazinz, your last couple steps I could not perform. I could not find where in tmpegenc they are?

'4. once on this make sure enable filter is checked
5. next select the filter "even-odd field (field adpation)"

6. now hit the scroll bar and watch the clip. if you selected the top field (step 2) and the picture looks fine, chances are you have the correct field. If the picture plays somewhat broken/choppy change the field and try it again. One of the fields will play fine while the other is choppy. Whichever plays fine is the field your clip is'

I have no idea where to find those.

Any other help?

[lenti_75]

there is difference....
i encoded dv file changing thr field order...and the video was jerky.

usually, the interlaced video is bottom first.....

strange

[mazinz]

those options are all in the same screen in tmpg where it shows what field order and picture size your clip is.

On the bottom right of tmpg (when you first open the program) is a button called settings. Clicking on that will bring up new tabs. Click on the tab called advanced. This is where you can change the field order and such. At the bottom of this screen you wlll notice quite a few options you can do (such as color correction, deinterlace, noise filters, etc). double click
on the deinterlace line and it will open a new window. It is in that window where you make sure the little "enable filter" box is checked and it also has a scroll down bar and this is where you can pick whatever deinterlace filter you need

[X-treme]

mazinz, Thanks.

I tried it for both top and bottom, and both appear to be jerky.

Not sure what else I can do for this one particular movie..?

[Abond]

Using such a program like ReStream you can change the field order without reencoding in couple of minutes. The problem is that the jerkiness can have other origin, not the field order, especialy if your clip is progressive. Therefore more info about the clip is needed.

[X-treme]

I've just tried another divx and the same problem occurs.

I do believe it's the field order anymore.

What info (gspot) do you need to determine what could be the problem behind the jerky video? It occurs every 10seconds or so.

[Abond]

I do believe it's the field order anymore.

I assume you don't believe, because otherwise the sentence have no sense
If the movies are divx, then they are 100% progressive (AFAIK) and the field order doesn't matter. What you can do is to look at the configuration of divx codec and to disable EVERY post-processing and quality settings. Try it again.
BTW do you have the same jerks when you play the file or only if you encode it in TMPG? I am asking because by default divx codec encode with a key frame every 10 sec (every 250 frames) - then your jerks are at key frame, but what it means I still don't know .
Good luck.

[X-treme]

*Do = Don't*

Abond, the divx file plays normal before encoding. It's only after I encode the file that it will jerk.

I'm not sure where, or what to disable when you said 'EVERY post-processing and quality settings'. Where can I find these?

As for the divx codecs, the video is xvid. Is that what you wanted to know?

Thanks for your help!

[Abond]

Aha, xvid. Well divx and xvid are different things, at least xvid is divx written backwards
What I wanted to say is the following: I imagine the sequence of events so that the avi is decoded to uncompressed format by the codec and frames are then encoded by tmpg - so between the avi and TMPG encoding engine codec works for decompressing. If postprocessing is on it can lead to unpredictable results for the encoder (TMPG). Now I don't know xvid codec - never used it.
Well, did you try to frameserve the avi from VirtualDub to TMPG?