A color level bug

Red Prince wrote on 5/16/2017, 9:27 PM

This was pointing out by someone at a different forum, but it is a bug that has been bugging me as well (no pun intended), so I shall mention it here.

The author of the original post used a JPEG file, but I have converted it to PNG to make it non-lossy for my own tests:

This file shows 256 levels of gray, numbered from 0 to 255. Opening it in an image viewer and checking the values of individual pixels with ColorPix confirms that the number listed at every level correctly marks the gray level.

Now, open the file in Vegas Pro (I tested it on v. 14 build 252) in the 32-bit format linear (see image below)

It changes the gray values despite asking for a straight 32-bit format with the gamma of 1.000. If you then click on the Save Preview (Best Full), this is what you get:

There, the gray levels are all wrong. For example, 53 has become 37, 37, 37 and 156 has become 145, 145, 145. This makes no sense, and appears to be a bug.

P.S. Please don’t tell me to submit a bug report. I’m old enough not to be bothered with things like that anymore. Let someone young do it and get the credit.

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Comments

Musicvid wrote on 10/16/2017, 9:38 AM

That's an interesting change in the post-Sony era.

Still, Vegas will map, not interpolate color information, as your histo indicated.

The gamma anomoly in float projects, which is present since Vegas 2, can be avoided completely by importing 8 bit media into 8 bit projects, and invoking appropriate downstream leveling.

Grading 8 bit source in a rich environment, as many seem inclined to do, seems to me a bit like putting mascara on a pig.

Adis-a wrote on 10/16/2017, 8:42 PM

Yes, it's "salvage what you can" kind of project.

Thanks, Musicvid!