The 1:1 mapping of Vegas Pro has always been one of my top features as it makes it simple for me, except of the meta data handling of some cases ...

@wwjd "thanks for all this. Are the levels changes noted above, listed in your graph in some way? I'm not seeing it."

I may have over-complicated this explanation re: the render quality tables.

To do a levels comparison required from a single source file to multiple output codecs files would take a bit of time. But I had already all of those files available from having previously done a Render Quality Comparison table, so I simply re-purposed the source and multiple output files at hand and used those files for the "Levels" test.

So when I did the Levels test I found one codec that appears to be "error by design", i.e. The Xavc-L codec when used to render out to UHD, from UHD source.

I used the methology as earlier suggested to you by @Musicvid, simply put the rendered output clip either above or below the source clip in VP and toggle/select either one or the other while viewing the Histogram, and observe if there are any changes of significance.

The "Levels" result did tie in with an anomaly I had observed previously with my Render Quality testing vis a vis Xavc-L, but that's the only connection with the Render quality table, other than using its files for testing.

The 2 screenshots below demonstrate what happens to the Histogram, using Xavc-L. The source file screenshot is on the left, the Xavc-L rendered output file screenshot is on the right.

I used an 8 bit 25fps UHD .mp4 clip as source this time to eliminate any confusion, I had previously used the original 10 bit 422 source file, but frankly its not necessary, the results are the same.

When I tested all of the other codecs listed in the Render Quality Comparison table the deviation between the 2 histograms was insignificant..

When I say Error By Design, I'm thinking of those long posts by Musicvid and others who extolled the virtues of VP not hand holding, but this appears to be so.

It may not have shown up previously because … It doesn't happen rendering out using FHD. In rendering out to UHD a lot of users would have already decided to output to 16-235, which it appears to be attempting, so it mostly went un-noticed. My 2 cents worth.

My interpretation of @Marco. test:

Vegas Pro is not part of the problem with changes in levels. The concept that appears to cause many people grief is that they think Vegas Pro should be part of the solution rather than be neutral.

"The concept that appears to cause many people grief is that they think Vegas Pro should be part of the solution rather than be neutral.“

Well said, imho.

WMV still uses RGB output space, I believe.

According to a Microsoft info the Windows Media 9 series is YUY2.

But WMV is strange in many ways (e.g. a WMV rendered file will never have correctly quantized frames). I only included WMV in this test because I remembered it's been the only Vegas Pro HD video output which did not match the 1:1 output mapping in all the time I used Vegas Pro. And I think something similar applies to a certain flavor of SD MPEG-2 output (which I did not include in my test – HD only).

@JN-
I tried to repro your result when rendering to XAVC-L but my results differ from yours. Again my rendered video is mapped 1:1, so a 0-255 source will maintain its level range (actually i will lose value 0 and 255 which are the only forbidden video data values, XAVC is very strict).

Assumed you still use a 8 bit project, any chance to share your exact render properties?

@Marco. Can I take it that you are only testing in UHD? I find no issue with FHD, as previously mentioned.

Also, the test UHD clip has to start at lower than 16 and has to end greater than 235. If its already 16-235 then its left as is.

"I find no issue with FHD, as previously mentioned."

I oversaw this, sorry. I only tested HD. Will check UHD later.

@Marco.

Ok, make sure also that your test clip(s) is wider than studio.

@JN-
I tested again with the full range grey scale and UHD. I now have a clear repro of what you showed above.

I then did some further tests and I found when rendering to UHD XAVC-L there is no mapping from full range to limited range but it is a simple data clipping to the section of limited range (with all data beyond being lost).
This is something never ever happened to any other of the Vegas Pro render types and I wonder why this happens. In the sense of how Vegas Pro uses to treat levels it looks like a bug to me.

@Marco. Yes, glad you can concur with my results. Perhaps you can query it with MagiDerek?

I wasn’t expecting any of the codecs to do this. As I previously mentioned, this does clear up an issue I had when comparing this codecs render quality with all of the others, this one wasn’t “behaving” like the others.

So, sometimes when looking for one thing you find something else.

Thanks for taking the time to confirm.

@JN-

This is something never ever happened to any other of the Vegas Pro render types and I wonder why this happens. In the sense of how Vegas Pro uses to treat levels it looks like a bug to me.

Nope. They're just all crazy, and need to learn levels better. No bugs exist, only features. :D :D :D

@wwjd Well said, imho. 😂

"Perhaps you can query it with MagiDerek?"

It's been reported now.

@Marco. Excellent, thanks Marco. A really unexpected outcome. Maybe the OP got more than he expected when starting this “final” thread on levels. Alls well that ends well.

WMV still uses RGB output space, I believe.

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According to a Microsoft info the Windows Media 9 series is YUY2.

Yes, RGB (0-255), YUY2 (4:2:2)

I used (for fun), but never once RENDERED out of almost all the other editors. When they render, do they all give you what you see in preview? I'm full aware editors SHOULD understand levels... but, shouldn't Vegas ALSO default to just give you what you see in preview? Would that solve this levels question from ever popping up in this forum again?

isn't that what preview is for?

I used (for fun), but never once RENDERED out of almost all the other editors. When they render, do they all give you what you see in preview? I'm full aware editors SHOULD understand levels... but, shouldn't Vegas ALSO default to just give you what you see in preview? Would that solve this levels question from ever popping up in this forum again?

isn't that what preview is for?

Is Vegas doing anything else besides giving you what you see in it's preview window? 🙂

Totally different question is why your media player isn't set up the same as Vegas. 😉

 

Is Vegas doing anything else besides giving you what you see in it's preview window? 🙂

Totally different question is why your media player isn't set up the same as Vegas. 😉

I am not having the issue, just asking on behalf of the masses that keep posting the question. :)

But, yes, its probably their PLAYER causing the issue

I think it's not even the players causing an issue but just a lack of awareness how levels work combined with a mixture of existing, missing, correctly and incorrectly use of meta data. And for the very case of AVC rendering actually Vegas Pro is setting wrong luma range meta data which then irritates some players/decoders.

Credits: @john_dennis @Marco. @Grazie @NickHope

Added: High/Low clipping indicators.

Download : https://drive.google.com/file/d/1m2pgPanYf6CGugJ_wBCsijvDO6xjOC3O/view?usp=sharing