601 color vs. RBG color for exporting

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DC

DC

Cinematographiliac
Using Avid Xpress Prop HD v5.5.3 with a 720p 23.976fps project. . .

Ok, a bit of confusion here. I've never run into this problem with my own Avid projects and my knowledge is a little gray in this area. I'm hoping someone could explain this thoroughly.

My friend, who I'm working on a project with, is trying to export a Quicktime movie from an Avid timeline. He was originally exporting it as 601 and the color (upon playback) was looking very washed out. I advised him to try exporting as RGB and when he did, the colors looked great.

I realize that 601 color is for broadcast and RGB is for a computer monitor. I guess what I'm trying to get at is should this Avid project be set to 601 and then exported as 601? I suppose the monitor would also have to be calibrated as 601 color with say, a Spider? Also, how does the Avid codec selector factor into this - should it be used?

What is the step-by-step configuration for setting up, working in, and exporting 601 color that will look proper on a computer monitor and television?

Just looking for the best all-around solution. I would appreciate any help with this.
 
I agree this area is a bit baffling. I tend to get this answer to the same question: "you export 601/709 or RGB depending on the final source for viewing"...which doesn't altogether help much, since I don't know what each final viewing source requires (computer screen, TV, DVD, whatever). I did finally discover that you export 601/709 to work on footage in After Effects. And I too would love to know what the best output is for a DVD on a regular TV...or plasma TV. I'm surprised someone hasn't come up with a chart for the most common configurations--you know, what is best export settings for After Effects, for DVD, for LCD, for web, etc.

Avid codec won't help you. My understanding is the Avid codec is only useful for certain applications when you want to export something and work on it in another program and then re-import it to Avid. So don't check that box.

I just burned a DVD for standard televisions using the RGB color and it looks good to me.
 
I hear ya. So far, I'm finding that RGB is solving a lot of our color issues. But 601?? Hmmm . . .
 
http://www.broadcast.harris.com/videotek/appnotes/Gamut.pdf

Not specific to Avid, but a good article about the difference in colorspaces.

A lot of your workflow in Avid is depending on what you're going to do with the video. Take DVD for example. The choice for export then is based on your MPEG-2 Encoder. Sorenson Squeeze wants a 601 colorspace so if you encode with Squeeze you export 601. Other MPEG-2 encoders expect RGB, so you export RGB.

Basically it all comes down to your IRE levels for black and white. 601 is a wider spectrum than RGB, so when you export 601 and are viewing on an RGB display it will look more washed out because you have a greater span of color displaying on a display that sees a more narrow band of color.

I think I'm rambling now and not really helping, so read that article and then come back with questions. It's a confusing subject, and I'm not claiming to be an authority on this, but maybe we can figure it out together.
 
601 is the spec for SD
709 is the spec for HD
RGB is ideal for computer display

'Your output will determine your choice' :)
 
My understanding is that internally, media in Avid is kept in the 601/709 colorspace. If you export it as 601, the data is unchanged, and the RGB values remain in the range 16-235. If you export as RGB, the data for each color gets rescaled to be in the range 0-255.

It is up to you to coordinate this with the application (your transcoder for example) that is consuming the data. Some applications let you choose, so you just make sure your choices match.

George
 
Thanks for all the info. We'll be doing some experimenting later tonight.
 
GeoMar said:
My understanding is that internally, media in Avid is kept in the 601/709 colorspace. If you export it as 601, the data is unchanged, and the RGB values remain in the range 16-235. If you export as RGB, the data for each color gets rescaled to be in the range 0-255.

It is up to you to coordinate this with the application (your transcoder for example) that is consuming the data. Some applications let you choose, so you just make sure your choices match.

George
Click to expand...

That was much more eloquent then how I tried to say it. :thumbsup:
 
sean90291 said:
Hey, DC, please let us know what the results of your comparison are.
Click to expand...

Will do. It might be a little while though. Last night we realized we have some more editing to do.
 
It is not so much an issue of how the media is stored, but how it is color corrected. 601/709 refers to the SD and HD color space which in 8bit translates to 16RGB for black and 235RGB for white. Computer monitors, film etc. can use the full RGB range of 0RGB to 255RGB (thus the RGB shorthand for the nomenclature).

When color correcting in Avid, scopes, autocolor correct, etc.. all assume the SMPTE television standard of 16-235. So when working for television broadcast deliverable, choose 601/709.

If compressing same color corrected sequence for the web, use RGB. The feature allows you to color correct once and easily deliver both TV, film, web, etc.

The confusion kicks in when third party applications render in a different color space than the one that was given to them. This can cause a shift in the gamut usually referred to as "my blacks seem washed out."

The Apple DVD Studio Pro is an encoder that assumes the material is RGB and will lift the blacks and crush the whites during the encode. This assumption leads to the washed out blacks since sending it a 16RGB black will end up making it 32RGB after the encode...

Other applications will render in RGB so the user needs to make sure the setting is correct on both the Avid and in the third party tool to ensure no shifting occurs.

If a file is rendered in RGB, selecting RGB for input while importing will change the levels from 0-255 to 16-235. Choosing 601/709 will leave the levels alone.

So users need to a quick test within the pipeline of all the tools being used.


Michael
 
This thread has been helpful... but im still having problems with this... mostly with inconsistencies going between avid, quicktime, and After effects. Here is a post i reciently posted on the Avid Forums with what i was finding:

Hello,

I've searched all around and still can't figure this out. Im working in DVCPRO HD. What do i want to render this out as for editing in After Effects? If i render it out as DVCPRO HD codec with RGB color space it looks good in quicktime but importing into AE it is too dark! If i render out in 601 it is washed out in QuickTime but looks ok in AE until i export it again into Avid... then it is washed out. Anyone have any suggestions on proper workflow for this? Also what should the export color space setting be from Avid when i export for DVD?

Thanks!

Update: I can;t seem to get Avid to change the color space of imported files. I exported out of AVID at 601 then reimported that clip with an import seting of RGB- in avid the the blacks were now too high. I tried importing at 601- still too high... it seems liek avid is not applying the conversion on import... any suggestions?

Update 2- Exported out of Avid with RGB. Reimported into avid- looks perfect... i tried importing at 601 and rgb and there was no difference- it looked good both times. BUT if import this RGB export in AE it is really Dark.
 
http://forums.creativecow.net/readthread/45/762709/762709?&archive=T

http://www.avid.com/exchange/forums/thread/187045.aspx

_________________


Avid’s filmmaker techniques for video

— tboyer on January 20, 2006

Avid’s Michael Phillips and Matthew Feury kicked things off this morning with a tutorial on useful techniques for integrating film-based techniques with the Xpress Pro HD workflow; attendees participated hands-on via HP xw4300 Pentium D workstations. Challenges include synching audio to video correctly and dealing with different color spaces (RGB vs. 601).

avidcolor.jpg

Avid Xpress Pro HD’s ColorMatch makes primary color correction easy.

Phillips described a particularly helpful workflow for making primary color correction a snap. It requires a bit of work up front but pays off in post. The key is using a Macbeth chart (about $60-80 retail), which shows a range of true colors and grayscale values. Shoot this in every location and lighting condition in your project (under a key light) and then import a digital version into Xpress Pro. Then use Xpress’s ColorMatch feature to match the chart within the footage to the digital version of the chart. Click on a grayscale value in the footage (”bad”), then click the corresponding value in the Macbeth chart (”good”), and click Match Color. Repeat for each value, and you’ve got a pretty good primary color correction for your scene.

Phillips and Feury also discussed challenges of using a double system for audio and video for both film and video shoots. One technique is using a Horita timecode generator to synch your solid-state audio recorder to your camcorder. Finally, the two showed off Avid’s pan and scan capabilities for outputting 16:9 material as 4:3.
 
A lot of people have problems with this and Avid, in their usual tradition, do a terrible job of explaining it in their manuals.

I recently color graded a short indie film and I spoke with one of the top colorist in the business about color space issues, so I thought I would share what I learned in simple, direct terms. Forgive me if any of this is redundant from other posts...

In 8 bit RGB, 0 is black and 255 is white. If an RGB project that has been color corrected to 0 black, 255 white is imported back into Avid as 601/709 then it will contain superblack (0 IRE) and superwhite (107 IRE).

Superblack and superwhite are there purely for luma keying purposes as they are outside the broadcast / DVD colorspaces.

If you import an RGB file as RGB then your blackest black will become 7.5 IRE and your whitest white will become 100 IRE, which is the full legal gamut.

It's usually easier to do graphics / comp work in RGB space, but the best workflow will depend on the other apps and video hardware you're using. If you are making color decisions for graphics, grades or comps from an external monitor, you need to find out if the video display hardware you're using is converting to 601/709 space for the client monitor output. Generally most do and you should be doing all your work outside Avid as RGB and reimport the results as RGB (the exception being if you plan on using superblack / superwhite to do luma keying inside Avid, in which case you would reimport as 601/709).

It doesn't matter what colorspace you're working in externally as long as you remember what space you're in. If you export as RGB, color correct to 7.5 / 100 IRE and then reimport as RGB, the image will look very washed out in Avid.

My workflow is to export as RGB, do all work in the 0-255 range (0 IRE-100 IRE) and then reimport as RGB. This assures that the gamut in Avid is legal and that I'm using the full range of tonal values.

If you export as 601/709, you should not let blacks go below 16 (7.5 IRE) or whites go above 235 (100 IRE), the exception being if you plan to key with superblack/superwhite in which case you would allow the colors in the area you wish to luma key to go out of range. You would then reimport your work as 601/709.

In this scenario all your blacks at 16 (7.5 IRE) and all your whites at 235 (100 IRE) would be in range in Avid and anything above or below would be the superkey areas.

I hope I didn't over-explain this, but it seems a lot of people are having problems with it,, so I just wanted to be as clear as possible. I hope some of you find this helpful.
 
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I'm wondering if you export from After Effects using something like the DNxHD codec, then it is automatically re-setting the RGB range of the After Effects project to 601 (16-235), making it entirely legal and compatible with Avid's color range..
 
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