We have installed a new machine (changing from Mac to PC windows 7), and new avid version 8.6.5.

We have started a new project, a film feature shot in an Alexa Mini, in Arriraw. The DIT, which is an excellent professional, is going to transcode on set, and is giving us DNx36 mxfs.

The import process is ok. Well, we cannot import the mxf directly. We must link them and then consolidate. But the image is ok.

The problem start when we export, because even with the “Keep levels as” option ticked, the image gets expanded to full RGB. And that is a problem because the image is already a full RGB so it gets too expanded. We have solved the problem, applying a Source settings lut (full RGB to video levels) to compensate for the “compulsory export lut”.

Anyone has seen something similar? Are we doing something wrong?We have done many tests and cannot find a clue. Besides, We have been plagued with inconsistent QuickTime behavior, which makes the same archive display differently in each machine (and I am not talking about the aspect of the image, but changes in the RGB values of the pixels). 

Thanks for any suggestion.

When you export are you using Same as Source or choosing the custom option?

Custom. they are h264 quicktimes archives. 

My understanding is the the 'Keep as Legal range' doesnt change anything because Avid assumes all the media is legal in the first place (ie in Rec709 terms within the 16-235 range), So I would say you are doing the right thing. 

However, if you were to set it to 'Scale from legal to full' it still doesnt actually change the values of the files, just sets a 'flag' somewhere in the metadata that tells other apps downstream (players, encoders etc.) whether or not to expand the range. I think that this flag is not always recognised by some apps.

I use Squeeze fairly often, but still find it confusing deciding whether or not to check that color levels export box - the output from squeeze frequently looks different depending on which player I'm using to preview; VLC, Windows Media or Quicktime.

I suspect the H264 export you are doing is taking what it believes to be a colour-legal file (although actually RGB/full swing) and it is the app applying the range expansion, not the Avid export.

Look at the settings of the export (H264) codec to see if there is an option to specify.

MattB

Once you move away from Same As Source all bets are of. Its then down to the QT backend to decide how to handle things.

yes keep as Legal shouldn't change anything it basically passes across levels as they are. But they could of course be full range within MC if ingested or graded like that.

Thank you both. 

I wll make some tests with same as source, just for the sake of curiosity. We do not have sorenson now, and so that is why we chose the direct from avid route.