DVD Field Order

Marco. wrote on 3/9/2005, 12:13 PM
Anybody knows why most commercial DVDs contain Upper Field First MPEG?

Some people say it is because Upper Field DVDs have better compatibility on standalone DVD players. I doubt. I think it is maybe because the master tapes they use contain Upper Field First and they simply try to contain this. Though - movies are progressive ...

All the Vegas DVD render templates use Lower Field First. I think this is because Vegas is primarly used with DV which has to be Lower Field First. But if this would really mean less compatibility with players ...!??

So I still wonder what's the reason for prefering Upper Field for DVDs in many cases.

Marco

Comments

riredale wrote on 3/9/2005, 12:46 PM
It's pretty obvious when field order is incorrect. It's also true that there is some confusion in the industry as to which field is the "upper," or "top," field, so perhaps it's just a question of definitions.

It might also be that the DVDs you refer to represent a film source (i.e. a progressively-scanned source). I wonder if the concept of field order is relevant for film sources--I really don't have the experience to know the answer.
B_JM wrote on 3/9/2005, 1:44 PM
a dvd can be either TFF or BFF

adding pulldown can yield TFF or BFF (from film source)

other pulldown (2:3:3:2) and staggered frame methods can still be any field order.
Also - a new thing is re-writing timecode to change effectively a 25fps to 22fps and adding a different pulldown (other combinations also) - this is done for pal conversions and also pal to pal time compression conversions ... the field order almost becomes meaningless ..

You can mix field order on a dvd - you can add mpeg with different field order together .



PAL dvd's are 'suggested' to be only TFF

NTSC - doesnt mater.

Cunhambebe wrote on 3/9/2005, 1:50 PM
Thanks for the input, BJ_M. I didn't know that. I always encode as BFF (Bottom Field First) because most the job here is NTSC. Didn;t know PAL should always be encoded as TFF (Top or Upper Field First) Thanks again for the input!
johnmeyer wrote on 3/9/2005, 2:17 PM
Some additional reading on the subject:

Upper or Lower field order..please help

[Edit} B_JM thinks that some of the information in the above link is incorrect, so I guess you should not take it as gospel.

Marco. wrote on 3/9/2005, 2:25 PM
Thanks for all the input!
Brian, you said PAL dvd's are 'suggested' to be only TFF. But why is it so? Is this kind of "official" suggestion, kind of standard? And - if so - why is the Vegas render template for PAL DVDs set to LFF then?

Marco
B_JM wrote on 3/9/2005, 6:50 PM
the Vegas render template for PAL DVDs is to LFF because the input with vegas is often dv ..

sonic foundry did the right thing and made the default a "safe" option in this case ..

and to be clear - a BFF PAL dvd is perfectly compliant in all respects ..

so why the suggestion of TFF for PAL? to be honest - i have no clue ... but in many conferences and spec examples and hardware chip guru late night slam sessions - as well as just reading - it has been brought up many times that PAL players (some anyway) play smoother or something with TFF (may be 2:2 pulldown also issue) ..

B_JM wrote on 3/9/2005, 6:53 PM
johnmeyer - that doom9 link should be removed from your post as it has some incorrect info


as well - it is a bit confusing for just answering the question and kinda goes off on a tangent ..

regards,

brian


johnmeyer wrote on 3/9/2005, 9:17 PM
that doom9 link should be removed from your post as it has some incorrect info

I added an edit to the original post with your warning.
rdolishny wrote on 3/10/2005, 5:26 AM
Are you suggesting if it's on the internet it's NOT true?

http://www.gullible.info

- R