Rocketcine-X Avid AAF/MXF Color Level Problem

[Anthony Young]

Trying to use the AAF/MXF export from Rocketcine-X. Process works great import AAF finds MXF material but colors are mapped wrong.

If I use the Rocketcine-X export to Quicktime with the DNX codec and choose 709 the colors are mapped wrong on input to the Avid. If I choose RGB they are correct.

Import settings on the the Avid are set to 709 (16-235) and the material fast imports.

Avid Symphony 4.03

This doesn't seem right.

What have I got wrong?

[MichaelP]

what have you set for output gamma in ROCKETCINE-X?

Michael

[Anthony Young]

I assume you are asking for the settings for Color Space and Gamma/Tone Space, they are both set to REC709.

Am I missing another gamma setting?

[Job ter Burg]

If I use the Rocketcine-X export to Quicktime with the DNX codec and choose 709 the colors are mapped wrong on input to the Avid. If I choose RGB they are correct.

Maybe I've misunderstood, but I thought that those QT settings for the Avid codec were asking you what the input values were. So if you choose RGB as input values, it should correct them to 709, if you choose 709 as input values, it will leave the levels untouched.
Just a thought...

[Anthony Young]

Job ter Burg thanks for the input.

When I import the AAF into the Avid and select any of the 3 options for "File Pixel to Video Mapping" it makes no difference the colors are mapped wrong and RocketCine-X doesn't give you an option on export. (or so I believe)

For Quicktime export out of RocketCine_X you have an option to set color levels to 709 or RGB. On import Avid gives 3 options for "File Pixel to Video Mapping" basically RGB, Dither, and 709. So I tested 4 options here are the results.

1. RGB export - RGB option import - no fast import/colors correct
2. RGB export - 709 option import - fast import/colors correct
3. 709 export - RGB option import - no fast import/colors correct
4. 709 export - 709 option import - fast import/colors incorrect

So:

I get fast import anytime I choose 709 makes sense.

1. Avid expects RGB receives RGB should convert to 709 ok
2. Avid expects 709 receives RGB should be no conversion but colors are correct why?
3. Avid expects RGB but recieves 709 should convert to 709 but colors are correct why?
4. Avid expects 709 receives 709 should be no conversion colors are wrong why?

I only understand what is happening in number 1.

Trying to understand

Thanks

A Young

[Job ter Burg]

For Quicktime export out of RocketCine_X you have an option to set color levels to 709 or RGB.

Yes, but what are you setting there? Source or destination? I think that setting is to determine _source_. So if your source is RGB, it should list RGB. Your destination will then be 709, but you cannot choose that seperately.

2. Avid expects 709 receives RGB should be no conversion but colors are correct why?

That's the weird thing about the nomenclature. If you select 709 you are not really making anything 709, you are telling the Avid to not touch the levels upon import. So, supposing that on export you told the compressor that the source was RGB, it might have created a 709 conversion of those RGB originals. When you bring it into the Avid, and tell the Avid it is 709, the Avid will leave the levels untouched.

3. Avid expects RGB but recieves 709 should convert to 709 but colors are correct why?

Well, if the source was actually RGB, and you told the compressor that the source was 709, then the compressor would not touch the levels. When you tell the Avid it is RGB, it will change the levels to 709.

4. Avid expects 709 receives 709 should be no conversion colors are wrong why?

Again, if you accept my assumption that the compressor setting in Quicktime is to determine the _source_ color levels, then all this makes sense. You tell the compressor to not touch the levels (which are RGB, but you tell it that it is 709), then you tell the Avid to not touch the levels (you tell it they're already 709), then you end up with the same RGB levels as the originals, which means they are off in Avid.

Again, I am assuming this, not having worked with Redcine nor Rocketcine yet, just knowing that this is how it works if I create a DNxHD QT file in for instance Quicktime Pro. I export, and tell the export settings the color levels of the original. If you assume that this is also the case in your examples, then all these level results make sense.

[Anthony Young]

Job ter Burg

I had wrongly assumed that referred to destination.

So if I follow your logic as it refers to color levels:

Import a 709 file and tell Avid it is 709 my result is a 709 file
Import a RGB file and tell Avid it is a RGB my result is a 709 file
Import a RGB file and tell Avid it is a 709 my result is a RGB file
Import a 709 file and tell Avid it is a RGB my result is a 709 file (I'm assuming the Avid is smart enough to not convert if values already exist.)

This also makes me assume that RocketCine-X is incorrectly creating MXF's using the RGB color levels.

For now I'll set the color level of the source file in RocketCine-X to RGB and import into the Avid with 709 as the source file selection.

Still looking for more input on the AAF/MXF color levels.

Thanks

A Young

[Job ter Burg]

Import a 709 file and tell Avid it is a RGB my result is a 709 file (I'm assuming the Avid is smart enough to not convert if values already exist.)

No, if you import a file that has 709 levels and tell Avid it is RGB, then it will raise blacks and lower whites of the file you are importing. When you tell Avid that the import file is RGB, it will remap 0 to 16 and 255 to 235. Whatever used to be 16 will now be somewhere around 30 and whatever used to be 235 will now be around 220.

This also makes me assume that RocketCine-X is incorrectly creating MXF's using the RGB color levels.

That's not the impression I get from your story. The source file for R3D is full swing rather than 16-235. By telling the compressor that the source is RGB, it will remap to 709 (16-235) during compression.

[Anthony Young]

No, if you import a file that has 709 levels and tell Avid it is RGB, then it will raise blacks and lower whites of the file you are importing. When you tell Avid that the import file is RGB, it will remap 0 to 16 and 255 to 235. Whatever used to be 16 will now be somewhere around 30 and whatever used to be 235 will now be around 220.

That was my original thought but I exported 2 files from RocketCine-X with the 2 different settings RGB/709 imported them to Avid with the 2 settings RGB/709 resulting in 4 clips. 3 clips appear to match the HD SDI output of the Rocket card. I assumed 2 would be good 2 would be bad. I will export and import again when I get into the office.

That's not the impression I get from your story. The source file for R3D is full swing rather than 16-235. By telling the compressor that the source is RGB, it will remap to 709 (16-235) during compression.

In exporting the MXF from RocketCine-X I don't have the option of setting the source file color setting. Importing the AAF into Avid the options to set File to Pixel Mapping (RGB/Dither/709) have no effect. The resulting file out of the Avid does not match the Rocket Card output blacks on the Avid are lower.

Here's where I get confused again.

Avid works in 709 colors so I would assume that RocketCine-X would be trying to create an MXF with 709 colors. If so the compressor has these options.

1. Starts with a RGB level file thinks it is a RGB level file and converts it to 709 resulting in a file that is correct.

2. Starts with a 709 level file thinks it is a 709 level file and doesn't convert the colors resulting in a file that is correct.

3. Starts with a RGB level file thinks it is a 709 level file doesn't convert the colors resulting in a file that is incorrect (0-255).

4. Starts with a 709 level file thinks it is a RGB level file converts it to a 709 resulting in a file that is incorrect.

My guess is they are not doing 1 or 2 because the resulting file is not correct.

Would it be #3 that is used resulting in lower blacks?

What happens in the conversion from 709 to RGB, because does Avid offers a dither option I am assuming they merge certain colors, and how is black and white remapped?

Sorry to ramble and thanks for your help and patience.

A Young

[MichaelP]

The settings for RGB and 709 are based on the user knowing what the color space of the incoming file is. If you check 709, then nothing gets changed during the import process as it assumes you are giving it a correct 709 color space file (ex: 16-235). But you can lie to it and the source file can be 0-255 and since it does not get modified, the resulting file will be 0-255 after the import.

If selecting RGB, the import process will always result in a 16-235 color space. What I need to conform is whether a proper 16-235 import with the RGB settings does a lift of the blacks -

On export, a properly color corrected 16-235 sequence can be exported as 709 or RGB where 16-235 gets mapped to 0-255. This is handy for some MPEG2 compressros that expect 0-255.

Michael