"Thorsten Froehlich" <tho### [at] trfde> wrote in message
> The terms "odd" and "even" are the correct technical terms which are used
in
> all technical literature and all (professional) software.  In fact I have
> never seen "upper" or "lower" been used before anywhere, and they don't
really
> make sense either when dealing with something that is counted...

I am very surprised that you have never seen "upper" or lower" used
anywhere.

Premiere has a project setting for "upper or lower field first" which it is
very important to get right.. Also a quick search on the web will throw up
numerous technical pages which refer to "upper" and lower"  fields, such as
this on google which includes technical pages from the Adobe site:

http://www.google.com/search?hl=en&q=upper+lower+field+video

There's also a good explanation of why "odd" and "even" are ambiguous on the
oft-linked-to Lurkers Guide to Video. There's a small section entitled
"Thoroughly Ambiguous: Avoid The Terms Even and Odd" half way down this
page:

http://www.lurkertech.com/lg/dominance.html

I accept that many specs assume that the reader appreciates that line
numbering starts from 1, but this is not universal.

> "upper" or "lower" ... don't really make sense either when dealing with
something
> that is counted...

But that is the problem. It depends what number you start counting the lines
from - 0 or 1. If you start from 0 then the top line is part of the even
field, but if you start from 1 it is part of the odd field. Some specs may
say that line numbers (or field numbers) start from 1, but there are a lot
of sources including Pov-Ray which start numbering from 0. Consequently if a
program only tells you that its output has the odd frame temporally before
the even field you don't know for certain whether the field containing the
top line is the earlier or later - and you need to know this. Once you have
imported this clip into Premiere you don't have to count lines, but you must
know whether the field which includes the top line (the upper field) is
temporally earlier than the other (lower) field otherwise your finished
project may playback on interlaced devices with jitter.

Colin







Never? The project settings of Premiere require you to set "upper" or
"lower" field first.



>
>     Thorsten
>
>
> A few references:
>
> * Bt848/848A/849A Single-Chip Video Capture for PCI Data Sheet
>   Brooktree Corporation
>
> * AD724 RGB to NTSC/PAL Encoder Data Sheet
>   Analog Devices, Inc.
>
> * LM1881 Video Sync Separator Data Sheet
>   National Semiconductor Corporation
>
> * QuickTime 5 API Reference
>   Apple Computer, Inc.
>
> * Media Composer 1000 User Manual
>   Avid Technology, Inc.
>
>
>
> ____________________________________________________
> Thorsten Froehlich, Duisburg, Germany
> e-mail: tho### [at] trfde
>
> Visit POV-Ray on the web: http://mac.povray.org

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