Re: AFX to DS-correct field order?

["Agustin Goya" <ds.forum(at)boltown.com.ar>]

This is whhat Ryan Answered a few days agoin this forum , it can't be better explained.

 

Boltown

Dominance refers to where video editing systems (the DS) consider 
frames to start on tape - between field 1 and field 2, or between field
2 and field 1 of the next frame.

Order refers to which lines come before the other lines in time in an 
interlaced frame that has already been captured from tape into our 
computers.

Even the DS Editing Guide gets it wrong and uses these words 
interchangeably when they shouldn't be.

To answer your questions:

PAL is f1 dominant, right?

No. The FIELD ORDER of PAL is field 1, upper field, first.

Why would the DS preset for PAL suggest 'even'?

The DS preset is telling you the FIELD DOMINANCE of the DS, not the 
FIELD ORDER. See below.


NTSC - from the DS Editing Guide
Field 1 (upper) contains ODD lines
Field 2 (lower) contains EVEN lines

720 x 486 NTSC - FIELD ORDER of lower field, F2, first

         1st field in field order                       2nd field in 
field order
   lower, F2, even line numbers [2,486]            upper, F1, odd 
line numbers [1,485]

The first field in the NTSC field order is the lower field, field 
number 2, containing all EVEN numbered scan lines.
The first picture scan line (line 1) is contained in the UPPER field 
- which corresponds back to NTSC FIELD 1. Therefore, DS sets its 
FIELD DOMINANCE to ODD (1 = ODD).


PAL - from the DS Editing Guide
Field 1 (upper) contains EVEN lines
Field 2 (lower) contains ODD lines

720 x 576 PAL - FIELD ORDER of upper field, F1, first

         1st field in field order                       2nd field in 
field order
   upper, F1, even line numbers [2,576]            lower, F2, odd 
line numbers [1,575]

The first field in the PAL field order is the upper field, field 
number 1, containing all EVEN numbered scan lines.
The first picture scan line (line 1) is contained in the LOWER field 
- which corresponds back to PAL FIELD 2. Therefore, DS sets its FIELD 
DOMINANCE to EVEN (2 = EVEN).

Some common field orders for other formats:

640 x 480     NTSC          upper field first
640 x 480i    ATSC          upper field first
720 x 480     DV NTSC       lower field first
720 x 576     DV PAL        lower field first
720 x 576     non-DV PAL    upper field first
768 x 576     PAL           upper field first
1920 x 1080i                upper field first

Cheers,

Ryan

----- Original Message -----

From: <wollinger(at)teleimage.com.br>

To: <DS(at)Softimage.COM>

Sent: Thursday, October 13, 2005 8:14 PM

Subject: Re: AFX to DS-correct field order?

> NTSC is lower field first in after effects
> 
> Citando 
philc <ds(at)mbaproductions.com>:
> 
>> Hello..
>> 
>> I have searched some of the 
earlier threads but can't seem to find a 
>> concise answer to my 
question...so here goes.
>> 
>> AFX artist is preparing motion 
graphics for our Nitris DS. The DS 
>> project is 1080i...what settings 
should the AFX artist use for exporting 
>> and what settings should I 
use on the DS when importing? Field 
>> order/dominance, codec, etc. 
Also what settings to use if project is SD 
>> 720x486?
>> 
>> Thanks...we have a lot of conflicting info coming from all sides 
here 
>> and need a solid "this is how you need to do it"!
>> 
>> -- 
>> Phil Coulloudon
>> Senior Editor / 
Compositor
>> Martin Brinkerhoff Associates
>> 
949.660.9396
>> 
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> 
> 
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