Considerations for color correcting PAL that's going out to NTSC at DVinfo.net

Glen Elliott · December 9th, 2004, 01:16 PM

Are there any considerations to keep in mind when I color correct PAL footage which I'm going to convert to NTSC MPG2 in my final step of workflow. How different are the two color spaces? Will the meticulous color corrections hold up when rendered out to NTSC? TIA

Rob Lohman · December 10th, 2004, 03:55 AM

If possible I would monitor it in NTSC color space. If you have a
DV Deck or DV<->Analog converter and a monitor or TV that can
show NTSC you can load the PAL footage in an NTSC project and
you can watch on the monitor how it looks (color wise) and how
your corrections are looking.

Glen Elliott · December 10th, 2004, 08:03 AM

My concern with that is I'd like to edit while I'm doing color corrections going along. PAL footage in an NTSC project plays at a very low framerate.

Is there a noticable difference between the two colorspaces. I know the whole 25fps, high vertical res, and 50hz instead of 60. But what are the differences in color- if any?

Speaking of hz- the highlights or hotspots in my PAL footage looks a bit stroby on my Sony Production monitor. If I watch a clip that is under exposed are just a bit darker in general it looks fine. But anything that is under bright studio lights I see a flicker...in fact anything over a certain luminance gives off this look. Could it be because PAL uses a 10hz differencial in refresh than I'm used to viewing in NTSC?

Rob Lohman · December 11th, 2004, 05:58 AM

Yes, there are differences in the PAL and NTSC color space. I don't
know what the exact differences are, but one (if you want to be
broadcast compliant) is that PAL has no broadcast safe levels etc.
No 7.5 IRE.

Normally you don't edit and color correct at the same time, and
personally I wouldn't do that. Concentrate on the editing first
(adding a letterbox mask at this point is fine for example). Make
sure the movie works and flows correctly.

Then start to worry about color correction and other effects
you might need (fancy title screens, computer effects, audio mixes
etc.). In this case it doesn't really matter if your computer plays
only at 5 fps since you don't need to see it in real-time.

I've recently done a color correction job on an NTSC project. I'm in
PAL land so I changed the project to PAL and watched on my TV.
This footage was already edited and I just added the coloring and
was usually just manually walking through frames with my cursor
keys or playing to see the overal effect (where framerate is not
important).

When I was "done" with some work I rendered out to PAL and
NTSC files so I could check the footage on the TV (PAL) and the
original NTSC version on my laptop to make some futher adjust-
ments if needed.

In my opinion this workflow works fine and allows you to directly
see how it should look in NTSC.

Rhett Allen · December 11th, 2004, 11:09 AM

PAL is 4:2:0 and MPEG-2 is 4:2:0, NTSC is 4:1:1
I would test it, and test it, and test it again. Just because you dump it in an NTSC timeline doesn't really give you any idea what it is going to look like when compressed with MPEG-2 and played back on TV. Take a few samples and run them through the whole process. You are running this multi-generations and have a lot of changes going on
PAL (4:2:0) - NTSC (4:1:1) - MPEG-2 (4:2:0)

Glen Elliott · December 12th, 2004, 07:47 PM

I'm not running the PAL footage in an NTSC timeline. I'm editing and color correcting in an entire PAL project/timeline. It's when I'm finished the project I'll output to NTSC MPG2.

Rhett Allen · December 12th, 2004, 07:59 PM

Take a small sample clip. Run it thru the exact same steps you are planning, all the way to DVD. Now look at the footage and compare it to what you started with.
You can make some minor changes to the source file and try it again, and again, and again.

December 9th, 2004, 01:16 PM	#1
Glen Elliott Wrangler Join Date: Apr 2003 Location: Philadelphia, PA Posts: 2,898	Considerations for color correcting PAL that's going out to NTSC Are there any considerations to keep in mind when I color correct PAL footage which I'm going to convert to NTSC MPG2 in my final step of workflow. How different are the two color spaces? Will the meticulous color corrections hold up when rendered out to NTSC? TIA

December 10th, 2004, 03:55 AM	#2
Rob Lohman RED Code Chef Join Date: Oct 2001 Location: Holland Posts: 12,514	If possible I would monitor it in NTSC color space. If you have a DV Deck or DV<->Analog converter and a monitor or TV that can show NTSC you can load the PAL footage in an NTSC project and you can watch on the monitor how it looks (color wise) and how your corrections are looking. __________________ Rob Lohman, visuar@iname.com DV Info Wrangler & RED Code Chef Join the DV Challenge \| Lady X Search DVinfo.net for quick answers \| Buy from the best: DVinfo.net sponsors

December 11th, 2004, 05:58 AM	#4
Rob Lohman RED Code Chef Join Date: Oct 2001 Location: Holland Posts: 12,514	Yes, there are differences in the PAL and NTSC color space. I don't know what the exact differences are, but one (if you want to be broadcast compliant) is that PAL has no broadcast safe levels etc. No 7.5 IRE. Normally you don't edit and color correct at the same time, and personally I wouldn't do that. Concentrate on the editing first (adding a letterbox mask at this point is fine for example). Make sure the movie works and flows correctly. Then start to worry about color correction and other effects you might need (fancy title screens, computer effects, audio mixes etc.). In this case it doesn't really matter if your computer plays only at 5 fps since you don't need to see it in real-time. I've recently done a color correction job on an NTSC project. I'm in PAL land so I changed the project to PAL and watched on my TV. This footage was already edited and I just added the coloring and was usually just manually walking through frames with my cursor keys or playing to see the overal effect (where framerate is not important). When I was "done" with some work I rendered out to PAL and NTSC files so I could check the footage on the TV (PAL) and the original NTSC version on my laptop to make some futher adjust- ments if needed. In my opinion this workflow works fine and allows you to directly see how it should look in NTSC. __________________ Rob Lohman, visuar@iname.com DV Info Wrangler & RED Code Chef Join the DV Challenge \| Lady X Search DVinfo.net for quick answers \| Buy from the best: DVinfo.net sponsors

December 10th, 2004, 08:03 AM	#3
Glen Elliott Wrangler Join Date: Apr 2003 Location: Philadelphia, PA Posts: 2,898	My concern with that is I'd like to edit while I'm doing color corrections going along. PAL footage in an NTSC project plays at a very low framerate. Is there a noticable difference between the two colorspaces. I know the whole 25fps, high vertical res, and 50hz instead of 60. But what are the differences in color- if any? Speaking of hz- the highlights or hotspots in my PAL footage looks a bit stroby on my Sony Production monitor. If I watch a clip that is under exposed are just a bit darker in general it looks fine. But anything that is under bright studio lights I see a flicker...in fact anything over a certain luminance gives off this look. Could it be because PAL uses a 10hz differencial in refresh than I'm used to viewing in NTSC?

December 11th, 2004, 11:09 AM	#5
Rhett Allen Major Player Join Date: Mar 2002 Location: Plano, TX Posts: 607	PAL is 4:2:0 and MPEG-2 is 4:2:0, NTSC is 4:1:1 I would test it, and test it, and test it again. Just because you dump it in an NTSC timeline doesn't really give you any idea what it is going to look like when compressed with MPEG-2 and played back on TV. Take a few samples and run them through the whole process. You are running this multi-generations and have a lot of changes going on PAL (4:2:0) - NTSC (4:1:1) - MPEG-2 (4:2:0)

December 12th, 2004, 07:47 PM	#6
Glen Elliott Wrangler Join Date: Apr 2003 Location: Philadelphia, PA Posts: 2,898	I'm not running the PAL footage in an NTSC timeline. I'm editing and color correcting in an entire PAL project/timeline. It's when I'm finished the project I'll output to NTSC MPG2.

December 12th, 2004, 07:59 PM	#7
Rhett Allen Major Player Join Date: Mar 2002 Location: Plano, TX Posts: 607	Take a small sample clip. Run it thru the exact same steps you are planning, all the way to DVD. Now look at the footage and compare it to what you started with. You can make some minor changes to the source file and try it again, and again, and again.