Need Help HD Output

ddm wrote on 10/7/2008, 12:42 PM
Ok, I'll try to keep this brief. I've got a Vegas (8c) project that I am trying to output to a file that a post house can use to create an HDCam SR HD master. The Vegas timelinet is a mixture of Cineform (3.4) avi's and stills.

I have rendered a Bluray mpeg2 file from this project and burned a Bluray and it is perfect. I am using default templates for everything.

I rendered, for the post house, an Avid dnxHD 220 quicktime movie that I figured would be something that they could deal with. For the most part, they could. I think their process was to put my rendered mov on a Final Cut timeline and render it out again to play it out to tape. That all worked, but the color space seemed to shift. From the description I got, it sounds like a computer RGB to Studio RGB shift. The footage is brighter than normal, brighter than the Bluray burn I did. I figured it was on their end, but I did just do a Standard Def render from my Vegas timeline to mpeg2 and burned a DVD from it and it, too seems a little too bright.

I've burned many standard def dvd's from this project, (from a standard def timeline with standard def cineform avi's) with perfect results, but something is happening now that I've converted everything to HD that I can't quite track. The Bluray file comes out great.

Any thoughts would be greatly welcomed.

Comments

farss wrote on 10/7/2008, 1:51 PM
The latest version of FCP can read Cineform files if they have the codec. That would seem the ideal interchange codec to use and should avoid any uncertainties.

Are you checking everything with scopes as you go?
If you've been working in 32bit then things get pretty messy, check here: http://www.glennchan.info/articles/vegas/colorspaces/colorspaces.html

Bob.
ddm wrote on 10/7/2008, 2:12 PM
I'm staying in 8 bit, original footage is all 8 bit. I was using the Vegas internal scope.

I would like to use Cineform, I asked the boys at the Post house and the only guy who'd heard of it said something to the effect that it wouldn't be high quality enough. Sounded to me like they don't have it. I might have to press the point, however.

I did notice in my quicktime render window that there is, on the Video tab, a "Compressed Depth" slider that defaults to "32 bpp color". I left it alone, not sure what that did/does.
farss wrote on 10/7/2008, 2:52 PM
You should get them to read the tests done by Pixel Harvest.
Cineform is better than SR and a lot cheaper. It's a crying shame that the better Cineform codecs don't work in Vegas.

Bob.
ddm wrote on 10/7/2008, 4:33 PM
I hear you. I usually find it a losing argument to try to tell a post house something they don't know... like the original footage is in cineform codec now, how will it be better using a dvcpro codec on top of that. Oh well. Onward and upward.
GlennChan wrote on 10/7/2008, 9:16 PM
I did notice in my quicktime render window that there is, on the Video tab, a "Compressed Depth" slider that defaults to "32 bpp color". I left it alone, not sure what that did/does.
32bpp = 32 bits per pixel, i.e. 8-bits for red, green, blue, and alpha/transparency.

2- It could be a quicktime gamma/colorspace issue. There might be a way to fix it by mucking with the metadata in the QT file... I have never done that myself because I just use workarounds (rendering to other quicktime codecs).

I can't remember what levels the DNxHD codec likes to see... I think you can set it in the DNxHD codec settings.

3- You should include color bars in the file you render... even a single frame of color bars in a 2-pop would suffice.
Do make sure that you are generating color bars that correspond to the levels in your video.

4- Scopes in Vegas may not be accurate. (I would assume that they are inaccurate, because that is the safe assumption to make.)
GlennChan wrote on 10/7/2008, 9:36 PM
What have you done with your levels by the way?

What I would do:
Apply computer RGB -> studio RGB conversions on all your stills. This will get your Cineform and stills into the same colorspace / this converts everything into studio RGB levels.

Nest your project into a new one, and apply a studio RGB -> computer RGB color corrector preset. This is assuming that your quicktime codec wants to see computer RGB levels. It's probably the case. But it might not, so they should check the color bars and your actual footage (preferably on real scopes, not FCP scopes which can be inaccurate).

ddm wrote on 10/7/2008, 10:43 PM
Thanks, Glenn. My levels have never been adjusted (color correction has been applied) but I've never applied a studio or computer rgb conversion. Most of the video footage has gone from HDV into an avid, hdv export from avid to m2t and then immediately converted to cineform. Since all of the dvd's and blurays I've created so far have been as desired, I always assumed that everything was ok. The rest of the footage is stills and various b roll that I've adjusted in Vegas to match the rest of the footage.

If I add color bars from the vegas library, what determines if it's computer rgb or studio rgb?

Thanks for the info. I appreciate it.
GlennChan wrote on 10/7/2008, 11:02 PM
The color bars are studio RGB / appropriate for studio RGB levels.

I have a chart here:
http://www.glennchan.info/articles/vegas/v8color/v8color.htm
ddm wrote on 10/8/2008, 12:17 AM
Great info, wow. thanks. Now here's my confusion... I've been working on this project for quite a while and I've been using a render to bluray and burning a bluray disk to basically color proof the edit on a bluray player on an hdtv. The bluray render and output are exactly how I want it. When I render that same timeline to the quicktime avid codec I get a render that's a little too bright (studio rgb, right?) I also got the same brightness on a standard def mpeg 2 render, which seems weird as the bluray render is main concept's mpeg compressor as well.