Whites crushed on render
 

Hi,

I'm looking for practical advice for a problem I have.

On Vegas preview window everything looks good (see image Before-render.jpg) and after I render it to mp4 file via Mainconcept templates it comes out with highlights crushed (after-render.jpg). Can you help me achieve the look that I see in my preview window (Before-render.jpg)?

I havent messed with any RGB conversions. Only done a lot of color correction with color curves in Vegas 8. Original files are MXF files from EX1 camera.

Thank you!

Sami

Oh yea?

http://glennchan.info/articles/vegas...or/v8color.htm

Sorry but I should have clarified that practical means step by step advice. I dont understand Glenns tables and the jargon.

Sami

We need one more bit of critical info.

Can you paste a screenshot of your project properties window? The one you get when you click File -> Properties.

dump vegas. you'll never get what you want without a lot of effort.

Bill...
I've been using Vegas for years....
And after more jumping around with levels and color space on my last project, I'm really starting to believe you...

I really hope Sony is listening. This really needs addressing.

Here you go. Thanks!

I'm curious. How do other programs handle this? I've used Canopus and Premiere Pro, and I never seem to recall having any issues. But to be honest, in working with Vegas Pro 8 in 32 bit mode, I've never had a problem rendering to DVD, mpeg4, or mpeg2.

But here's the thing. I do all my work in Vegas in 32 bit and Studio RGB. When I render to things that want studio RGB everything is perfect. When I render to things that want Computer RGB, they don't seem to spread the gamut, they just fit my signal inside the bigger color space, and everything works as intended.

I know this seems to be a big problem for folks, and maybe I am just lucky that my normal workflow makes it a non-issue.

Is Computer RGB for things on the web and computer screen and StudioRGB for things like DVD and broadcast?

Sami

Yep, that's what I figured. You are working in an 8-bit project.

So your preview window is showing computer RGB. The full 0-255 colors. When you render to a format that is destined for broadcast, the values get clipped to what broadcast can show. On Glenn's chart that is Studio RGB or values from 16-235. A subset of the Computer RGB signals.

If you were working in Vegas with Studio RGB then you could output to any codec without the clipping. It's an ugly PITA problem. And one reason I stick to working in 32 bit mode.

Bingo. That's it exactly.

well, not exactly. There are codecs that EXPECT computer RGB and there are codecs that EXPECT studio RGB. It really makes no difference what your final distribution venue is; all that matters is what RGB range the final codec you're rendering to EXPECTS to see as input. As Sami has said, Glenn's article is way too confusing to use in day to day practical application.

Ok,

Here is what I know.

I work with Cineform based AVI files on the timeline. I work in 32 bit only. I get no color shift that I can determine going to mpeg2, mpeg4, or WMV. By keeping a constant workflow, I eliminate problems and inconsistencies that could cost me time. Before I worked in Cineform, I worked with huffyuv compressed AVI files in the same workflow with the same results.

Cineform is the ONLY codec I use consistently, because it works consistently in Studio RGB. It's very predictable and accurate. While CFHD works in YUV color space, its I/O is studio RGB. Canopus HQ is an equally dependable and color accurate intermediate.

Great minds think alike! LOL! :)

Seriously, I just started using Cineform a few weeks ago and love it, but I was getting by with exactly the same workflow using HuffYUV files. Now my projects move MUCH faster because the Cineform files are a LOT smaller.

If I apply 32bit should I put levels FX on the video output with Comp to studioRGB conversion?

Comp to Studio levels do not work with 32 bit. And I have found them unnecessary. That would probably help you with this 8-bit issue though. You really ought to spend some time absorbing Glenn Chan's page. It covers the problem fairly thoroughly though it can be a bit tricky to follow.

Clipping whites are not the only issue here. Image clarity/sharpness is also being affected. What res are you rendering to? What is your source res? What bitrates are you using within your render?

There are so many variables, that to say its this or that without knowing what the destination actually is (aside from mp4) is not going to solve the problem.
By the looks of how the whites have flushed out I'd say its a codec issue NOT a colour space issue.

When I convert my project to 32 bit without any color space conversion the whites get crushed so there must be some kinda conversion I have to do?

Here is an example:
In 8bit:
http://www.dvinfo.net/conf/attachmen...1&d=1203280538

After changing project to 32 bit:
http://www.dvinfo.net/conf/attachmen...2&d=1203280538

Perrone...

I've been around and around on this issue. No one seems to want to listen to what you're saying about Glenn Chan's page.They just continue to wonder why they're crushing the shadows or blowing out the hi-lites. It's hopeless.

Bill, you must understand that for people who havent been around this stuff for decades its not peanuts to go to a page and go, oh thats it.

Im getting a lot of information and it's all very overwhelming. For someone who already knows this stuff it must be obvious. Ive read Glenns charts a hundred times. I've been studying this issue a lot. Its just not clear to me yet. That is why Im asking people like you for help.

Now I was adviced to change my project to 32bit and was told that I shouldnt do an RGB conversion. But now the whites are clipping.

Sorry if Im trying your patience but once I get this I will be able to help others with the problems and it wont be on your shoulders anymore.

Sami

Sami..

I agree. This is a very frustrating issue, even for myself. And Chan's white papers are also very confusing. So much so that I've abandoned Vegas. They've done their users a great disservice with version 8. The nearest I've been able to come to a conclusion is quite the contrary to what you've been told. I was told to stay in 8-bit. Sothere you have it...no one really knows. Some codecs will convert the output, regardless of what bit depth you start with.

ok ok ok! So, I decided to ditch rendering to Mainconcept mp4. im now rendering with WMV and everything looks good. Im doing it from 8bit project.

Render looks good in Windows media player. Looks good upped to Vimeo and all these look like it looks in the Vegas preview window.

So thanks for your help. To recap my problem was that I was rendering with a codec that changes the RGB and creates problems.

Thanks again. And Bill, I just shot a music video today using your picture profile settings :) Ill put it in the EX1 footage section once I finish editing. I find your PP works like a miracle in a sunny weather outdoors.

Sami

yeah. I've had good luck with WMV and the Cineform codec, as I wrote above. rendering to the mainconcept codec is very problemmatic. This can be a real issue if you want to render to a DVD. I've been using TmpGenc or Procoder for my mpeg2/DVD renders; and, that seems to work very well.

Hi Sami,

I think I may be able to offer a concise answer for you here as I have struggled with your exact problem, and it is very confusing.

Do this test:

Take a very short EX1 clip and add it to a Vegas timeline with your properties set to 8 bit, and with NO studio to Computer RGB conversion done. Then render it out to a file using Mainconcept settings here http://eugenia.gnomefiles.org/2007/1...-for-vimeo-hd/.

Next, change the settings to 32 bit (or do a Studio to Computer RGB conversion). Render the same clip using the same settings.

If your results mirror mine, the end files will look the same.

What this essentially tells you is that Mainconcept render is essentially doing a studio to Computer RGB conversion only on files that have not already been converted. So, if you have already brought up your whites in Vegas, this will blow them through the roof.

I hope that helps!

Ok, step-by-step, here is what I would do.

1- Drop your clips into a 8-bit timeline. (The instructions below won't work for 32-bit.)

2- (Optional) Map the superwhites into legal range.
Add Levels filter
output start = 0.006
output end = 0.920

3-
If rendering to the main concept MPEG2 or MPEG4 encoder:
Do nothing for step 3.

If rendering to WMV (the normal way via file-> render as, not WME):
Apply a second Levels filter. Use the "studio RGB to computer RGB" preset.

4- View those files outside of Vegas. e.g. View any WMV files in Windows Media Player.

------------

Here is what's happening:
A- Most cameras, the EX1 included, will record illegal values which are also referred to as "superwhites". These are values that are above white level and usually will end up clipped. For these values to get clipped is normal.
It's arguably a bad way of designing cameras.

In any case, you can map the superwhites into legal range to avoid this. This is what step 2 does.

B- In Vegas, you need to manually wrangle your color space conversions sometimes. (Arguably, this is bad design / not easy to use especially since you need to know what conversion you need to perform.)

In any case, this is what step 3 does.

C- Vegas 32-bit mode adds two additional layers of complexity (compositing gamma, and codecs behaving differently)... we avoid this in step 1 by going with a 8-bit project.

D- Vegas previews and scopes may not be accurate/appropriate. This is what step 4 addresses.

If you:
A- Start a 32-bit Vegas project.
B- Render from there to a MPEG4 (or MPEG2) format using the main concept encoder.
C- Bring that clip into a 8-bit Vegas project, or change the Vegas project to 8-bit.

You'll see the clipping that the original poster is seeing. This happens because the superwhites are getting clipped off (superwhites are the values above legal maximum white).

Regarding the comments about my article being confusing:

1- I'd be interested if there was a simpler way of explaining this stuff.

2- It's kind of complicated because you have to pay attention or be aware of at least six/seven different things (maybe more):
A- The video preview may not be correct.
B- The scopes may not be correct.
C- The behaviour of the codecs of all your source material. studio or computer RGB
D- The behaviour of the codec you're rendering to.
E- That the behaviour of some codecs changes depending on 8-bit or 32-bit mode.
F- Compositing gamma (affects whether the studio<-->computer RGB conversion presets do what they say)
G- Cameras record superwhites / illegal values above white.

On top of that, hopefully your monitoring is correct (and there's a number of potential screw ups there).

Would it make more sense if I pointed out those seven things upfront??

3- The goal of my article was that you could figure out the right steps for any situation, not just particular situations.

The instructions in my first post of this thread only covers a particular situation and doesn't apply to other cases. There are many different ways of getting the color wrong- that includes Cineform (e.g. render from Cineform to MPEG2; you'll see different results in a 8-bit versus 32-bit Vegas project). So you need a way of figuring out how to get the right levels in any situation.

Thank you very very much Glenn for the detailed advice.

I took the MXF file to Vegas 8bit timeline.
I added levels effect and added Comp RGB to Studio RGB.
(Whites look gray on Vegas preview window)
Rendered as mainconcept MPEG4.
(Whites look as they should be!)

So in essense what Im seeing in Vegas preview window is NOT what comes out after render to Mainconcept.

So wow! Im getting good results now with MPEG4, excellent!

One question though, why did you point out step 2 is optional? If I dont do the RGB conversion the whites dont look proper after render. So in essence I must do it dont I?

So the way to work with this is to do do the RGB conversion just before render. This way you see what you get in the preview window.

[QUOTE=Glenn Chan;854698]Ok, step-by-step, here is what I would do.

1- Drop your clips into a 8-bit timeline. (The instructions below won't work for 32-bit.)

2- (Optional) Map the superwhites into legal range.
Add Levels filter
output start = 0.006
output end = 0.920

3-
If rendering to the main concept MPEG2 or MPEG4 encoder:
Do nothing for step 3.

If rendering to WMV (the normal way via file-> render as, not WME):
Apply a second Levels filter. Use the "studio RGB to computer RGB" preset.

4- View those files outside of Vegas. e.g. View any WMV files in Windows Media Player.

------------
Hi Glenn,

That is not what I am experiencing. Speaking only for the EX1 files, if I start as you say, with 8 bit Studio RGB and the clip originally had superwhites, do not adjust levels, and convert without Computer RGB conversion, superwhites will clip.

The same is true if I hand Mainconcept 8 bit computer RGB or 32 Bit. It will blow the superwhites, unless they are leveled down beforehand.

The easy workaround for me is to edit in 8 bit Computer or 32 bit and be sure to hand off no superwhites.

As I noted above. If I take a file in 8 bit studio, 8 bit computer or 32 bit and hand them to Mainconcept with *no* other adjustments, the end product is the same.

I don't believe I recommended this. Re-read the instructions... step 2 would be to add the Levels filter with particular settings.

It's not a RGB conversion. It's optional... try it both ways.

If you don't do step 2, then you get standard/normal levels and the superwhites will be clipped. This is the "standard" way of doing things. The clipping happens because the camera is doing something not according to standards.
You can do step 2 to gain additional highlight detail (it compensates for the camera's non-standard behaviour).
Both ways of doing things are correct.

Randy, I don't know the steps you used (it's not clear to me from reading your post). That could be why we are seeing different things???

In any case, the steps I outlined give the correct results for 8-bit Vegas projects with EX1 (or MPEG2) footage.

.......not wanting to cause an argument, but I'm a broadcast cameraman of many years with very limited technical engineering knowledge. I'm new to NLE and have been trying my hardest to learn.

Admittedly, the way Vegas works with colour correction and levels etc etc can be very very confusing (it certainly is to me), but I found Glens articles and advice easy to understand and VERY useful! It's amazing that there is someone out there generous enough to share their knowledge for free! Thanks Glen.

Since I became freelance many years ago it's hard to pester engineers and editors, especially since we all seem to be so much busier than the good ole' days!..

....just throwing that into the mix!

Thanks Stuart.

Hi Glenn,

I am actually doing nothing other than setting properties for each of the 3 options, adding a clip to the timeline, and rendering using Mainconcept. The only exception is with studio to computer, where I am applying the stock FX to the clip. I get the same results in each case.

Best, Randy

Randy, I simply don't see what you're seeing.

Adding a Levels FX to a clip with either the "studio RGB to computer RGB" or "computer RGB to studio RGB" preset will change image and the resulting rendered file compared to rendering out the clip without any FX. Adding FX will change the look of the rendered file (unless you disable the FX somehow, e.g. via the half-moon icon in the Video preview window).

So I think you're drawing erroneous conclusions from your testing or doing it the wrong way (e.g. unintentionally disabling your FX).

Hi Glenn,
It is less the 32 bit and 8 bit computer RGB that interested me. It was Studio RGB passed off to Mainconcept. The first two render as they look in Vegas, which is expected. Studio RGB, however, looks dramatically different in Vegas (as it should), but renders to look the same as the other two with Mainconcept. There is really no FX to disable in Studio or 32 bit, as I am not applying any. This is very intersting if we are getting such a different result. You are testing with EX1 files?

Thanks,
Randy

Randy, I don't think I understand what your steps are.

What are you referring to here when you say "studio RGB"?

What is the clip?
What effects are applied to it?
What are the project settings and compositing gamma?

And what are you referring to when you say "computer RGB"?

I've tested with a EX1 MXF file I've downloaded.

Here are some pics from mainconcept mp4's renders.

1. Vegas timeline (8bit project, no FX)
2. no FX render (Whites clip very hard)
3. Glenn suggested levels (Whites are slightly whiter and blacks slightly blacker than on the timeline)
4. Computer to Studio RGB with levels FX added (Looks exactly the same as on the Vegas timeline)

Jpegs are done by opening mp4's in photoshop and saving as jpegs. Vegas timeline is a screen crab.

Please take a look at the pics and tell me your opinion. I think this is a very interesting topic and Im very close to understanding the procedure and hopefully making amazing videos that look the way I want :)

Again thank you for all your help!

Sami

PS. If anyone wants I can provide this EX1 MXF file for testing.