Rec.709 colorspace, AE, Cineform & HD/DV output at DVinfo.net

Stephen Armour · January 23rd, 2008, 02:37 PM

A open question for any knowledgeable persons in this area:

What is the best COLOR workflow/practise to use with CF'ed (V1 HDV>1920) input, and productions done in PP3, AE, Flash, Encore, etc.?

The reason for asking is that PP CS3 does not have "color management", while AE CS3 does. How should we treat Rec. 709 when shuffling files between the two programs, especially in light of the fact that the final output will be used for DVD (Rec. 601), Bluray (Rec 709) and for the web.

It seems if we output with 709 turned on in AE, every generation has darker luminance. If you pull the output back into AE, it's even darker when you next render!

Our brains are getting hot trying to understand this.

Light, light, light! We need light from someone with a true grasp of the issues, please.

David Newman · January 23rd, 2008, 02:58 PM

Turn off color management in AE, things work better.

Glenn Chan · January 23rd, 2008, 03:40 PM

Rec. 601 and 709 have different transfer functions.

Life is easier if you pretend that they are the same and do nothing to try to convert between the two. This is usually what's done in HD<-->SD conversions (including the high-end). To do it right would take a lot more effort and potentially introduce problems, whereas if you do it "wrong" no one will notice. And if no one notices then it doesn't really matter.

Sergio Sanchez · January 23rd, 2008, 06:02 PM

The color managment in AE works best if you use it as a display lut only. The best thing tough is to calibrate the monitor using a ICC profile that match your needs. In this case use a Rec709 ICC profile.

When working in AE with cineform files, it is not convenient to use the color managment in the project preferences, it is beter to use the profile converter.
for previewing or even output a video with it if your project need it.

The thing with the color managment is that it tryies to transform the gamut of the monitor to match the one in the video. So it is displayed "correctly".
But truth is that it is not perfect, the gamut is only an interpretation of the program, and each program can have its own interpretation.

I agree with the David, the best thing is to leave it a it is. By default it will use the ICC profile that your monitor uses. So if you balance your monitor acording to rec709 specs. It will display your footage in 709 all the time.

Bill Ravens · January 23rd, 2008, 06:48 PM

What Glenn says is true...BUT.....it's not really the smoke and mirrors that Glenn loves to imply it is. Glenn, please don't take offense, none meant. You know more than I'll ever know but what Glenn said is "Rec. 601 and 709 have different transfer functions". This is true, but, it's a confusing way of saying that it's really simple to convert for REC601 to REC 709. Vegas makes the process easy, simply by applying the "Convert from studio RGB to Computer RGB" FX. I don't know what PP# does for this function. Don't pretend they're the same...they most definitely are not.

And it makes the difference whether you blow out the whites and muddy the blacks, or not.

David Newman · January 23rd, 2008, 07:02 PM

"Convert from studio RGB to Computer RGB" does not convert from 709 to 601. The white and black are in fact the same for 709 or 601. They both have the same (very very close) gamma curves. The difference is the RGB to YUV colorspace transforms. If you rendering in RGB, then 601 vs 709 issues are gone. i.e. If you render RGB to a SD MPEG encoder, it will internally, automatically convert the RGB values into 601 YUV values. The only time 601 to 709 issues come up is in direct YUV conversions. That will not happen in AE or Vegas, as they are both RGB only tools.

Bill Ravens · January 23rd, 2008, 07:11 PM

Quite right, David!! Once I go thru NEO HD, the intermediate file is in R'G'B', and the process is vey simple. I am a wee bit surprised that Neo doesn't feed out a progressive file. It still converts to "upper fielf first, interlaced. I use HDLINK as an integral part of my workflow. Now, if only Vegas would I/O 10 bit.

David Newman · January 23rd, 2008, 07:43 PM

It is a progressive file, Vegas just reports it wrong.

Bill Ravens · January 23rd, 2008, 07:44 PM

LOL...aha!

Sorry, I guess I'm out of context. I just took delivery of my EX1. I'm stunned. This is a very amazing camera, and I'm just scratching the surface. CFHD is working well. Thanx.

Stephen Armour · January 23rd, 2008, 08:20 PM

Quote:

Originally Posted by David Newman

Turn off color management in AE, things work better.

Ok, I'm relieved...I thought I was the only one confused.

After reading this:
http://www.theasc.com/magazine/april...um2/page6.html

it really seems like the bottom line is still calibrating a monitor and in the final run, just basically trusting your eyes, and .... as you observed...turning off the management in AE. Okay. Makes sense. It really looked bad anyway!

But we should still turn on the "use BT.709 YUV" in CF settings, right?

My how confusing! No matter how you stack it up, video production is still one third magic, mixed with one part skill, and one part luck. And to think I did my first video production in 1984...

Check our our new "Creation" trailer on http://www.lightinaction.org - done with a V1, CFHD and some nice music/transitions, from DigitalJuice.

Oh, BTW, the color correction was done in AE, with the management turned OFF.

January 23rd, 2008, 02:37 PM	#1
Stephen Armour Major Player Join Date: Dec 2005 Location: Natal, RN, Brasil Posts: 900	Rec.709 colorspace, AE, Cineform & HD/DV output A open question for any knowledgeable persons in this area: What is the best COLOR workflow/practise to use with CF'ed (V1 HDV>1920) input, and productions done in PP3, AE, Flash, Encore, etc.? The reason for asking is that PP CS3 does not have "color management", while AE CS3 does. How should we treat Rec. 709 when shuffling files between the two programs, especially in light of the fact that the final output will be used for DVD (Rec. 601), Bluray (Rec 709) and for the web. It seems if we output with 709 turned on in AE, every generation has darker luminance. If you pull the output back into AE, it's even darker when you next render! Our brains are getting hot trying to understand this. Light, light, light! We need light from someone with a true grasp of the issues, please. __________________ http://lightinaction.org "All in the view of the LION"

January 23rd, 2008, 02:58 PM	#2
David Newman CTO, CineForm Inc. Join Date: Jul 2003 Location: Cardiff-by-the-Sea, California Posts: 8,095	Turn off color management in AE, things work better. __________________ David Newman -- web: www.gopro.com blog: cineform.blogspot.com -- twitter: twitter.com/David_Newman

January 23rd, 2008, 07:02 PM	#6
David Newman CTO, CineForm Inc. Join Date: Jul 2003 Location: Cardiff-by-the-Sea, California Posts: 8,095	"Convert from studio RGB to Computer RGB" does not convert from 709 to 601. The white and black are in fact the same for 709 or 601. They both have the same (very very close) gamma curves. The difference is the RGB to YUV colorspace transforms. If you rendering in RGB, then 601 vs 709 issues are gone. i.e. If you render RGB to a SD MPEG encoder, it will internally, automatically convert the RGB values into 601 YUV values. The only time 601 to 709 issues come up is in direct YUV conversions. That will not happen in AE or Vegas, as they are both RGB only tools. __________________ David Newman -- web: www.gopro.com blog: cineform.blogspot.com -- twitter: twitter.com/David_Newman

January 23rd, 2008, 07:43 PM	#8
David Newman CTO, CineForm Inc. Join Date: Jul 2003 Location: Cardiff-by-the-Sea, California Posts: 8,095	It is a progressive file, Vegas just reports it wrong. __________________ David Newman -- web: www.gopro.com blog: cineform.blogspot.com -- twitter: twitter.com/David_Newman

January 23rd, 2008, 03:40 PM	#3
Glenn Chan Inner Circle Join Date: Jun 2003 Location: Toronto, Canada Posts: 4,750	Rec. 601 and 709 have different transfer functions. Life is easier if you pretend that they are the same and do nothing to try to convert between the two. This is usually what's done in HD<-->SD conversions (including the high-end). To do it right would take a lot more effort and potentially introduce problems, whereas if you do it "wrong" no one will notice. And if no one notices then it doesn't really matter.

January 23rd, 2008, 06:02 PM	#4
Sergio Sanchez Regular Crew Join Date: Feb 2007 Location: Mexico Posts: 176	The color managment in AE works best if you use it as a display lut only. The best thing tough is to calibrate the monitor using a ICC profile that match your needs. In this case use a Rec709 ICC profile. When working in AE with cineform files, it is not convenient to use the color managment in the project preferences, it is beter to use the profile converter. for previewing or even output a video with it if your project need it. The thing with the color managment is that it tryies to transform the gamut of the monitor to match the one in the video. So it is displayed "correctly". But truth is that it is not perfect, the gamut is only an interpretation of the program, and each program can have its own interpretation. I agree with the David, the best thing is to leave it a it is. By default it will use the ICC profile that your monitor uses. So if you balance your monitor acording to rec709 specs. It will display your footage in 709 all the time.

January 23rd, 2008, 06:48 PM	#5
Bill Ravens Join Date: Nov 2001 Location: santa fe, nm Posts: 3,264 Images: 10	What Glenn says is true...BUT.....it's not really the smoke and mirrors that Glenn loves to imply it is. Glenn, please don't take offense, none meant. You know more than I'll ever know but what Glenn said is "Rec. 601 and 709 have different transfer functions". This is true, but, it's a confusing way of saying that it's really simple to convert for REC601 to REC 709. Vegas makes the process easy, simply by applying the "Convert from studio RGB to Computer RGB" FX. I don't know what PP# does for this function. Don't pretend they're the same...they most definitely are not. And it makes the difference whether you blow out the whites and muddy the blacks, or not.

January 23rd, 2008, 07:11 PM	#7
Bill Ravens Join Date: Nov 2001 Location: santa fe, nm Posts: 3,264 Images: 10	Quite right, David!! Once I go thru NEO HD, the intermediate file is in R'G'B', and the process is vey simple. I am a wee bit surprised that Neo doesn't feed out a progressive file. It still converts to "upper fielf first, interlaced. I use HDLINK as an integral part of my workflow. Now, if only Vegas would I/O 10 bit.

January 23rd, 2008, 07:44 PM	#9
Bill Ravens Join Date: Nov 2001 Location: santa fe, nm Posts: 3,264 Images: 10	LOL...aha! Sorry, I guess I'm out of context. I just took delivery of my EX1. I'm stunned. This is a very amazing camera, and I'm just scratching the surface. CFHD is working well. Thanx.