COW Tutorials: After Effects Working with Broadcast-Safe Colors

[Andrew Kramer]

Nice tutorial Aharon, Good safe method, works very well.

You make my tutorials look cheap ; )

_______________

Client: Well, lets move on we can fix that in post
Editor: This is post.
Client: oh.

[Pascal Desfoux]

Hi Aaron,

Does your values works with PAL?
Thanks for your energy !
Pascal

[Jochen Hirschfeld]

Hi Aharon,

thanks for doing these nice tutorials. I check them out quite often. Today I watched the one on broadcast safe colors.
Sounds great. Only one question:

How do you treat the resulting movie? Do you import it as RGB or as 601?
AVID e.g. allows you to import footage either with RGB or 601 luma setting.

Thanks for your time, Jochen.

[Annaël Beauchemin]

[VanHagen] “How do you treat the resulting movie? Do you import it as RGB or as 601?
AVID e.g. allows you to import footage either with RGB or 601 luma settin”

That’s what i’m wondering too… if the editing software interprets the resulting file correctly (most do), then RGB 255 is set to YCrCb 235 and RGB 0 to YCrCb 16. The RGB colorspace can be seen as a subset of YCrCb.

But it’s still possible to get chroma unsafe value when going from RGB to YCrCb…

[Aharon Rabinowitz]

Like I said, the method isn’t perfect, but I’ve handed this off to editors who have treated this the same way they treat any other footage – which is usually as RGB.

I have never had anyone report an issue – that 235 cap has not failed me yet…

though depending on the tape transfer itself that stuff can get messed up anyway – We once received a master and a copy where the maser was within scope, and the copy was so far out of scope it was like listening to bees nest when it buzzed. Something was wrong with the 2nd VTR which somehow boosted the color. Only proves, no matter how hard you try, someone, somewhere can mess things up.

But again, if you do it this way, and import the way you normaly import footage, you should have no problem.

Regretibly, I’ve done very little work in PAL. I’m hoping some of our non-america based AE artists or editors can weigh in here.

—————————————-
Aharon Rabinowitz
aharon(AT)yahoo(DOT)com
http://www.allbetsareoff.com
—————————————-
Creative Cow Master Series DVD
particleIllusion Fusion Volume 1
available @ http://www.pIllusionFusion.com

[Sam Moulton]

isn’t it true that some codecs expand the video range to the full 255 and when capturing video then compress it back to 235 when you go back to tape? seems like I heard that somewhere.

[Aharon Rabinowitz]

That’s news to me – which is cool because i like learning new things.

If I understand you correctly, then that means that you wouldn’t need to worry about safe color. Any idea what codec that is – perhaps a propriatary codec for certain video systems – I’ve never heard that before, but i wouldn’t be surprised, though I can think of a designer or 2 that would get all in a huff because it downgrades all the colors on export… (the same way my tutorial does)

When you say codecs, are we talking lossless or lossy? There’s a huge difference. Compressed lossy codecs tend to blow out colors a lot – the opposite of what you described.

—————————————-
Aharon Rabinowitz
aharon(AT)yahoo(DOT)com
http://www.allbetsareoff.com
—————————————-
Creative Cow Master Series DVD
particleIllusion Fusion Volume 1
available @ http://www.pIllusionFusion.com

[Andrew Kramer]

Okay here’s a short explaination,
If you compositing in AE with just avid 601 video, render the final video to tha avid 601(yuv) codec and then import to avid using the 601 conversion. Now if you only have RGB Graphics (pretty much anything else besides video you know is 601 or YUV) Render final video to an RGB Codec and then import into avid set as RGB. Now if you have both 601 and RGB Video, this Levels adjustment will work to correct the RGB parts to be safe within the 601 or YUV format (but you must cap only the parts you know to be RGB adding this levels adjustment to 601 footage will result in excess data loss). Then you would render to the 601 and import using the 601 to avid.

Now a side note:
Essentially if you use this Levels Cap effect on your RGB motion graphics or RGB whatever, this cap would keep the color in the 601 or YUV colospace so essentially you could render from after effects in the avid 601 codec import as the avid 601 and so long as everything was limited properly you will be good.

Now if your working at RGB you can render to RGB import to avid as RGB, are there still unsafe colors? possibly.

Here I made sort of a RGB to YUV calculator inside of Excel for those of you who want to check values basically it is an equation that converts
RGB number values to YUV number Values.

https://www.videocopilot.net/RGB.zip

Basically it takes the RGB and uses this calculation.
Y = 0.299R + 0.587G + 0.114B
U = − 0.147R − 0.289G + 0.436B
V = 0.615R − 0.515G − 0.100B

As they say its better to be safe than sorry. no pun intended.
But another analogy also comes to mind maybe not as well known…

When you cut the mold off of the end of a good piece of cheese you better believe that you’ll be throwing away some cheese that is still good, but you’d rather be safe than sorry. Now replace cheese with video and mold with dynamic range.

Alright this took some time so I think it’s only fair that I let you know that a self narrated After Effects training dvd is coming soon, it will have tons of tips and tricks and effects and 50 percent funnier jokes.

Okay i’m out.

Andrew

[Sam Moulton]

i did some work on a canopus dv system a while ago and there was an option to expand or not to expand. Don’t know much about it, but it seemed to work great. we just left everything as it was and when the tape was checked on a scope it was just fine. no fouled up color anywhere.

some time ago i also read that matrox does this. I’m basically a mac user and not much of a pro so I don’t know much about codecs other than dv and i’m experimenting with sony hdv also in fc.

[Andrew Kramer]

“Now if your working at RGB you can render to RGB import to avid as RGB, are there still unsafe colors? possibly.”
Meaning if you don’t use the cap levels effect. Just to clarify.

Andrew