Confused about a progressive PAL DVD with supposedly bottom field first

[Matthew]

Bitrate viewer reports the following (on a vob from the middle of the movie).

DCT precision: 10
Pic. structure: Field
Field topfirst: No
DCT type: Field
Quantscale: Nonlinear
Scan type: Alternate
Frame type: Interlaced

Darim easy changer also reports bottom field first.

Now by itself the DVD being reported as interlaced means pretty much zero, as this is rather common in region 4 DVDs even when the DVDs are progressive (although from memory usually such DVDs would be zig zag rather than alternate, however Memento also had interlaced/alternate combination despite being progressive).

Using DVD2AVI it is clear that the video is not interlaced as there are no lines when advancing frame by frame.

I encoded 4 samples using CCE, all with upper field first unchecked.
-Interlaced/alternate, top field first
-Interlaced/alternate, bottom field first (achieved with pulldown)
-Progressive/zigzag, top field first
-Progressive/zigzag, bottom field first (achieved with pulldown)

The sample involves 2 people walking and all samples appear okay on the tv, as far as I can tell. No jerkiness etc.

Anyway, I'm confused about the field order. Specifically, I thought progressive material was always top field first.

Any advice/explanations appreciated :)

[auenf]

for Progressive, it doesnt actually matter if its tff or bff, but for CCE it does.

http://forum.doom9.org/showthread.php?s=&threadid=42434

read Tsui's post.

Enf...

[Matthew]

Thanks for the reply.

Well I've already gone ahead and encoded it as progressive (with upper field first unchecked...as always...I know from past reading that box should never be checked) and didn't switch the field order with pulldown. Burned on an RW and it seems to play fine.

Talk about a botched encode on the original DVD...I think it's CBR as well (albeit ~8 Mbit).

Oh well I guess that's the end of the matter. Although it still would be nice to know why field order doesn't matter for progressive video streams. Then again I probably couldn't understand it :p