[Tig] 720p Tape to Tape color correction doc

Thu Oct 11 11:43:52 PDT 2007

  Below is a document I sent to our colorists on how to work with this correctly but before that....
The DVC Pro deck does not step very well under daVinci or TLC control.  When trying to determine the mark, watch the burn in TC from the VTR to decide which field.  
 We've also done the conversion to 1080i and back mode and that does work....
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  As we've seen when working with HD formats, unexpected operational issues come up from time to time.  This is certainly true of the 720P HD format.  The issue with this format is the 60 frame based nature of it and integrating that format into existing 30 frame or 60 field equipment.  The format consists of 60 complete frames though on tape the timecode is presented as 30 frames with a field one and two.  You would think that it would work normally with any 30FPS based editor.  The problem with 720P is there is not an actual field identifier in the video sync signal of this format which causes a problem identifying which is the field of interest from the timecode / video relationship.  This is especially true when detecting and marking correct frames or fields when tape to tape color correcting 720P footage.  There is a method though that will make it work correctly.... 

  When you get the tape you will be color correcting;

1. Take it to a DVC Pro machine that will step in fields and look at the first few events/ cuts.  (If you don't have one that  steps in fields or can dub to D5, it will work better.)
2.  Note which field they occur on.  
3.  Route the deck you will be using into the HD daVinci input.
4. Open a daVinci session and the 720P configuration.  Once you have picture lock, DO NOT SWITCH ANYTHING INTO THE INPUT!  Explanation to follow below... see #3
5. Turn on the scene detector and play the beginning of the tape.
6. Once the daVinci detects the first few scenes, stop and look which field is indicated in the list.  If it matches the events you checked previously at the VTR, you can proceed.  If it is on the wrong field, open the TLC configuration window, open the EDIT tab, and press the TOGGLE button ONLY ONCE!!  (See below #5)
7. Delete the events you have created previously and re~scene detect the beginning of the tape.  It should now be on the correct field.
8. Once you've finished detecting the tape, you MUST turn off the scene detector.
9. Open the TLC Configuration window. Open the EDIT tab and press the TOGGLE button only ONCE!  
10. You are now ready to work on the session.

Note: if while testing the scene detector you find the system is detecting the correct field, you still MUST follow the steps 8 & 9 once the tape has been scene detected.

Things NOT to do.

1. At this time the color correction timing delay for 720P is 2.  Do not change the number to try and correct the color timing. ( NOTE: this timing for Crawford System, your number will probably be 0)
2. DO NOT turn the scene detector back on once you've finished scene detecting the list and have clicked the TOGGLE button and are color correcting the tape!  The daVinci will detect the event one frame/field off and each event will have two marks!  You can step the tape and place a mark manually though you will have to pay close attention to which field the event takes place on and set the field identifier correctly. (IE, one dot for field one and the colon for field two.)  Press the F1/F2 button to place correct mark.
3. DO NOT switch ANYTHING else into the color corrector once you have established the correct timecode phase!  If you do, you will have to recheck the field dominance again as this timing becomes ambiguous once the video into the system in interrupted.
4. You will most likely have a tape with all field one marks though with 720p it certainly can have mixed fields.  With mixed field tapes, you should follow the above procedure correctly to minimize field color correction pops. You will probably not get a tape with all field two marks.  If so, something was wrong when making the tape as no one uses field two dominate editing....unless they did something weird. 
If everything is on field one, the exercise above is much easier.    
5. The toggle button changes the field dominance timing from one to the other each time it's clicked.  If you click twice, it will not have changed anything! 

David N. Warner 
V.P. of Post Engineering 
Crawford Communications
3845 Pleasantdale Road Atlanta, Georgia 30340
(d) 678.421.6814 (p) 404.876.7149 (f) 678.421.6715
(e) dnwarner at crawford.com (w) www.crawford.com

Shouldn't VITC be the order of the day? I'm sure the HDD5 has both
embedded LTC & VITC that should be readable in still mode. Does that
make a difference?
Jim DeLuca

-----Original Message-----
From: tig-bounces at tig.colorist.org [mailto:tig-bounces at tig.colorist.org]
On Behalf Of NCHAWDHRY at aol.com
Sent: Saturday, October 06, 2007 11:31 PM
To: amartinelli at ringsidecreative.com; rob at colorist.org
Cc: tig at colorist.org
Subject: Re: [Tig] [Fwd: 720p Tape to Tape color correction]

Thanks to Rob Houllhan, Cinelab for supporting the TIG.
 ====

Thank you all for your input. There really is no answer except to
convert the tape to 1080 or go through the list and check every mark to
make sure it is coming in on the correct field. Unfortunately, even as I
jog the tape, the DaVinci is not denoting whether it is a field one or
field two by way of a comma  or semicolon.

The F1/F2 button on the upper right hand side does the trick as far as
changing the marks between field one and field two.

Nadeem

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