VP18 - Notes on the 8 bit full level option

Marco. wrote on 8/3/2020, 11:40 AM

In Vegas Pro 18 there is a new pixel format project setting which is "8 bit (full level)" and which is the default setting now.

When 8 bit full level is selected Vegas Pro tries to conform all input media luma levels to computer RGB levels to provide proper levels for the internal preview.

That means:

Vegas Pro checks if the input video file is RGB or Y'CbCr. If it is RGB no level transformation will be applied (because RGB data is meant to be computer level).
If the input video file is Y'CbCr Vegas Pro looks for the color range meta data. If there is no such meta data, Vegas Pro assumes the color range is limited and applies a studio levels to computer levels transformation (because Y'CbCr video usually is meant to be studio levels).
If the Y'CbCr video meta data for the color range is "limited" Vegas Pro also applies a studio levels to computer levels transformation.
If the Y'CbCr video meta data for the color range is "full" no level transformation will be applied.
If the input media is a photo or grafic file format no level transformation will be applied.
If there's the need to switch the input level you can do this by opening the file property window(s) of the selected file(s) and manually set the color range option (this works both from the timeline and the Project Media window).
If you render a project with the project's pixel format set to 8 bit full level, by default Vegas Pro will apply a computer level to studio level transformation for the output file and automatically set the output file's color range meta data to "limited".
In the render window's project tab you can switch this color range output option to "full", thus no computer level to studio level transformation will be applied and the output file's color range meta data will be set to "full".
Note that not all video formats support such a color range meta data. In this case the color range usually is used as "limited" for all Y'CbCr media.

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Comments

Howard-Vigorita wrote on 5/27/2021, 1:55 PM

After a bunch of back and forths with zcam, I think I have a reasonable workaround. I don't want to lose the Vegas feature of working full range internally. But I can't have it altering the range or levels of zLog2 clips before the lut's applied. It would be nice if I could exempt this particular footage from auto-range conversion with a "Don't Tread on Me" media switch. Lacking that, my workaround is to patch the media metadata to re-mark it as full range without altering its video stream. I think this is less intrusive than applying the lut with a transcode before pulling it into Vegas. Or doing a conversion back to studio levels with a levels fx ahead of the lut fx. Or marking the project limited and putting a computer-to-studio fx on any of the other clips that need it. My preliminary of this approach looks good.

Blaine-WItherow wrote on 3/15/2022, 3:32 PM

RE: full range, Waveform setting 'Studio RGB' turned off. I don't understand the color bar test signal. With these settings, it is low. When I render it and look at it, it still is low (as observing in Vegas Pro 19). I thought it would convert it to full color levels. Obviously I am not understanding everything in this thread.

Musicvid wrote on 3/15/2022, 5:15 PM

Don't use the legacy "Studio RGB" Waveform setting with the Full Range Project Setting. They are redundant insofar as the scope display, which you do not want.
In a Full Range Project, you will set the desired full range values to read 0-255 on the waveform. The render will automatically be 16-235 (assuming a YUV delivery codec), the correct REC 709 Limited output levels for most playback and delivery. The Vegas Preview is not a Playback monitor, so if you bring the rendered REC 709 output file back into Vegas, the colors will look flat and washed out.
This article explains it all the way it was before the Full Range project settings were introduced fairly recently. It will make good backstory reading for you, and perhaps clear up some of the confusion regarding Full Range Projects as you learn. I've been at this particular issue for eleven years, since a bunch of us oldtimers started our research in 2011.
https://www.vegascreativesoftware.info/us/forum/pc-to-tv-levels-a-comedy-of-errors--107325/

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