Upper Field/Lower Field

rrrrob wrote on 3/19/2009, 9:22 AM
Can any one tell me if NTSC DVD video is typically encoded in upper field first (UFF) format?

My understanding is that you should encode/render video and DVDs in UFF format when creating a DVD for television display, but I am wondering if there is a way to determine the format (upper or lower field first) of a video I am importing for use in Vegas Video.

Initially, I thought Vegas automatically analyzed the video for proper pixel aspect and field order, and assigned those properties for you, so that when you clicked on the clip properties, the info already there was identical to what the video was to begin with, but I have discovered that is not the case, as often the pixel aspect is wrong, so I assume the field-order is not necessarily correct either.

Are all commercial DVDs encoded in UFF format?

Comments

Stasoid wrote on 3/19/2009, 11:50 AM
The field order should remain unchanged throughout the whole post-production process. Your final product, DVD must have the same field order as your raw footage. If the camera shoots in TFF(newer AVCHD camcorders), you then encode your DVD as TFF, if the camera was BFF (all miniDV) then the DVD is BFF as well.

It is a challenge though when you deal with mixed TFF and BFF footages within the same project.

Unfortunately VMS doesnt allow you to change field order when encoding MPEG2 off the timeline. It's always BFF, therefore all TFF source footages are being encoded incorrectly.

Commercial DVDs (movies) are usually non-interlaced at 23.97fps.
rrrrob wrote on 3/19/2009, 12:27 PM
most commercial dvds i have seen appear to me to be interlaced, but beyond that, I can't tell if they are UFF or LFF.

As far as I can tell, VMS does allow you to select in your project properties LFF or UFF when encoding MPEG2, so I am not sure why you say all video is encoded LFF...

I do realize I should be using the same field-order through the entire process...I am assuming that since my software (DVD2AVI) is telling me that my video source is interlaced (not progressive), that it is probably UFF since it came from a DVD that plays on a TV, but I am trying to find out if there is a way to know for sure what the field order is so that my subsequent editing, encoding and output in VMS and DVD Architect is correct.
Stasoid wrote on 3/19/2009, 1:10 PM
All those mpeg stream analyzers read field order flag which does not nesseseraly tell you correct field order. The only way to determine a field order of an unknown third party footage and to be 100% sure is to try both settings and create two DVD disks and see how they play on a standalone DVD player.

In VMS I tried to create a DVD from my UFF footage with UFF project settings but when playing that DVD disk its field order appeared to be reversed so I just assume the MPEG encoder in VMS has fixed BFF settings unlike Vegas Pro where you can change field order of the output file to whichever you like.

musicvid10 wrote on 3/19/2009, 1:24 PM
"Initially, I thought Vegas automatically analyzed the video for proper pixel aspect and field order, and assigned those properties for you,'

You have to set the Project Properties yourself. The "automatic" way to do this is to click Project Properties, then click the folder icon that says "Match Media Properties" and select the input file. Then when you click "OK" the project properties are the same as your media properties, including dimensions, PAR, and field order.

Then, when rendering, the DVD templates take care of everything for you. Just select one of the DVDA Templates, for instance, and render. Even if the template says the output field order is different than your source, don't try to second-guess it. Vegas is one of the very best programs at getting the field order right. In the very rare chance of an error, you would see it instantly in the the output.
rrrrob wrote on 3/19/2009, 8:02 PM
The "automatic" way to do this is to click Project Properties, then click the folder icon that says "Match Media Properties" and select the input file.

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OUTSTANDING--thanks for your help on that one! I just checked some media from a DVD...it comes up as Lower Field First as someone said earlier...why is this, when I THOUGHT video to be displayed on a TV screen is supposed to be encoded in UPPER field first????
musicvid10 wrote on 3/19/2009, 9:37 PM
TV doesn't care.

Either the source field order is correct or it isn't. Again, if it isn't you would know it right away.

You are way overthinking this -- let it go for now.
musicvid10 wrote on 3/20/2009, 10:27 AM
I was looking for this last night, but just found it again today -- older, but interesting, if not essential reading:

http://lurkertech.com/lg/fields/