Pixel Format, Videoscope Studio RGB and the Level FX

karma17 wrote on 7/10/2024, 1:49 PM

Just got myself a little confused today and wanted to double check on a couple of things. Some of my questions came after reading this article on Superwhites.

https://mattdavis.pro/2012/07/12/dealing-with-109-whites-the-footage-that-goes-to-11/

1. If editing 8-bit video, and the waveform monitor is set to Studio RGB, does the Pixel format also need to be appropriately set to to 8-bit legacy video? I ask because I notice a difference in the videoscope display based on the Pixel Format settings.

2. If the video scope is set to Studio RGB, does this mean that 0% on the waveform monitor represents a code value of 16 and 100% is a code value of 235?

3. And last, if an 8-bit video is intended for broadcast on You Tube or Vimeo, is it necessary to use the Levels FX to adjust Computer RGB to Studio RGB?

I was going to say that I'm asking this for a friend, but it is just for my own info.

Thanks!!!!

Comments

john_dennis wrote on 7/10/2024, 2:52 PM

Please state Vegas Pro version. Levels handling changed in Vegas Pro 18.

mark-y wrote on 7/10/2024, 4:59 PM
  1. In Vegas Pro 18 and higher, the pixel format should normally be set at 8 Bit Full Range, regardless of Y'cBcR or RGB video source media.
  2. Do not use the Studio RGB Waveform Display with Full Range Project Format. It is an erroneous, or nonsense combination.
  3. No, not in VP18+ with the Project Properties set at 8 Bit Full Range.

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.

  • https://www.vegascreativesoftware.info/us/forum/vp18-notes-on-the-8-bit-full-level-option--122749/
  • 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.

 

karma17 wrote on 7/10/2024, 5:53 PM

Thanks for all this clarification. Extremely helpful!! Using V21, so I'm in the 18+ club.It really sounds like Vegas does a lot of the decision making under the hood now. Really nice to know. This wasn't the same vibe I got out of reading the Help documentation. Thanks again.

karma17 wrote on 7/10/2024, 6:17 PM

I just wanted to make sure I am not a purveyor of bad information. So in the above example, which was shot in Sony AVC, it would be YCbCr, recognized by Vegas, and Vegas auto-leveled it, so to speak, and that is why it shows already at 100% in the waveform monitor without me having to do anything else to it other than making sure the correct settings are applied.

Am I correct in saying that?

Thanks again!!

mark-y wrote on 7/10/2024, 7:19 PM

Yes, that is correct, and even more than previously, it's best to not overthink the project settings; there are now 11,468,800 ways to get it wrong, approximately, and still only one way to get it right!

💩😈👹💀👻👽😵😨😱👺😪😡😖😫😣👿

karma17 wrote on 7/10/2024, 9:25 PM

Thank you mark_y. I really appreciate the help. Actually, I was doing a tutorial on the difference between Cine 1 and 2 and was going to tie it into Vegas and looking at the scopes, but before I knew it (and after reading the Help docs) I found myself in the weeds. So again, much thanks. It makes sense for now.

RogerS wrote on 7/10/2024, 10:30 PM

To see the difference in scopes between the two use 8-bit legacy.

In 8-bit full you can also change the color range to full for Cine 1 to see the clipped highlights (though that will mess up the shadows- need to convert those back to studio range with a levels Fx). 16-255 is why I don't use Sony Cine 1- a little bit more dynamic range but at the cost of workflow headaches.

Howard-Vigorita wrote on 7/10/2024, 10:31 PM

.... And last, if an 8-bit video is intended for broadcast on You Tube or Vimeo, is it necessary to use the Levels FX to adjust Computer RGB to Studio RGB?

@karma17 Not sure about Vimeo but YouTube assumes all uploads are rendered limited-range (studio levels) and remaps the range to full-range upon upload, whether it needs it or not. So the crucial thing is to let Vegas render limited-range, which is the default in all its render templates. Setting the Vegas project to 8-bit full-range looks just like what YouTube does to a limited-range render after you upload it.

The only time you might want to use the range fx is if you set your project to limited-range but want the Vegas preview to look like YouTube full-range. But you need to disable that range-fx in Vegas before you do the limited-range render. Otherwise it'll end up with a double-dose when YouTube does it again. Since limited-range is no longer the Vegas project default, I've gotten away from setting projects to limited range and messing with the Vegas level fx or extensions like SeMW.