Tmpgenc color space?

[Gerald Webb]

Hi all,
Ive got a Cineform 1080p file i'm trying to downsize and convert to mpeg2 for DVD.
1st time using Tmpgenc rather than my old method of Vegas- Virt dub- then back to Vegas for mpg2 encode.
All going well except my lovely First light color grade which is 16-235, is getting smacked down brutally by Tmpgenc which produces a blackened over saturated DVD file (it does do it quick though :)
Does anyone know a way to maintain the sRGB color space through Tmpgenc?

[Phil Lee]

Hi

I think this is because the Canopus codec doesn't want studio levels.

Try putting a Studio to Computer RGB filter on the video output to the Canopus codec, that hopefully should work as that will expand the range to 0-255, and then TMPGEnc when applying it's equivalent of the opposite filter, i.e. computer to video levels will then bring it back again and all will be well with the world.

Regards

Phil

[Gerald Webb]

Little confused Phil,
I'm using Cineform, or are you saying that Tmpgenc uses a Canopus codec?
Do you mean,
Re export from Vegas with an sRGB to cRGB filter on, thus making the clip 0-255 coming out of Vegas?
But, Can you encode a Cineform clip 0-255? I thought it was 16-235 by default.
Or am I better to export to Lagarith therefore it becomes 0-255
Argh! So much testing to do, so little time. Lol
My kingdom for a foolproof workflow .

[Phil Lee]

Hi

Sorry I did mean Cineform!

Yes try a studio to computer level filter on it.

Regards

Phil

[Roy Feldman]

What version of Cineform do you have? I let Cineform do the resizing by exporting to Cineform (usually a smart render) then putting it through HDLink and resizing there, taking Tmpgenc out of the mix altogether, works only with neo and above.

[Mervin Langley]

Interesting. I just tried that. but you still have to create the DVD compliant file with Tmpgenc right? Or are you doing something different?

[Gerald Webb]

Yeah, HD Link will do it, but Virtual dub or Tmpgenc will do it nicer :)

Been mucking around with this and Googling for a day now, finally getting somewhere,
Tried the sRGB to cRGB global filter out of Vegas, twas no good, just made it darker again out of Tmpgenc.
Found a hint on another forum which led me the right way,
In First Light, you can manipulate your source image in your authoring preview window, so,
Had scopes going in First light (which shows on your vid in the authoring program),
and,
had the Histogram on in Tmpgenc as well,
It was then easy to see what was going on with the levels.
Ended up having, as an example, one clip was set to-
Exposure= 1
Contrast= 1.122
Saturation= 1.030
Gain= 0.652
Gamma= 1
Lift = 0.16

By compressing the RGB parade, what this gives you is (in the Vegas preview) a very washed out soft looking horrible video.
but in reality it drags back all of the detail that is lost to clipping at both ends of the spectrum.
When dropped into Tmpgenc or Virtual dub, all of the highlights that were clipped come back, all of the detail in your blacks that was lost is now back also.
It was quite eye opening, one scene that had bubbles floating through the air, previously were just whitish, now have all different shades of colors in the bubbles that were clipped before.
I feel like re grading everything Ive done, lol.

[Phil Lee]

Hi

I think gamma is normally 2 something for most video, the different gamma level is probably what is throwing things out. If all gamma is 1, then setting the project properties to 32bit (full range) and set gamma at 1 (the default for full range) might also resolve it without tweaking elsewhere.

Regards

Phil

[Marc Salvatore]

Gerald,

Which version of TMPEG and Sony Vegas are you using? I've been using TMPEG Xpress 4 to convert my Cineform HD masters to MPEG-2 DVD successfully for a while now. Also how are you color correcting in Vegas? Are you using a calibrated monitor or just the preview window in Vegas? That could be your problem. The DVD could just be reflecting what your footage is really corrected to based on an inaccurate monitor.

Regards, Marc

[Gerald Webb]

Hey Mark,
64 Vegas 10 and Tmpgenc 5.
Re the monitor, Ive been using my second LCD as an external preview monitor with Vegas Color Management set to srgb.
I think Phil was onto something when he said that Tmpgenc expects 0-255 and its not getting it, how to fix it, I dont know.
My way described in the above post works really well but in the end I shouldnt have to change my image when going between software.
Cineform yuv is 16-235, and Tmpgenc is 0-255, its easy to see when you look at the 2 RGB parades at the same time, flatline black in the Cineform clip is shown no where near the bottom line on the RGB parade in Tmpgenc. Its a level line roughly where 16 would be. Its the same at the top end as well.
I have my work around for now :)

[Mervin Langley]

FirstLight uses 0-255.

[Marc Salvatore]

They may have changed something with TMPEG 5. (might be an option in the settings?) Do you have a copy of ver. 4? I have no problems using TMPEG 4 to convert my Vegas Cineform masters to DVD (confirmed this last night). Also make sure your scope settings in Vegas are set to (7.5 IRE: OFF / Studio RGB: ON) This will affect the waveform monitor and if not set properly you will see false black levels on your waveform monitor.

I am currently using a Blackmagic Intensity card to send my signal from Vegas to the component inputs of a Sony professional SD monitor. I have it calibrated to NTSC color bars. I make my CC adjustments mostly in Firstlight (also using the Blackmagic card preview) and keep an eye on my picture and RGB waveform. I then double check it in Vegas on the waveform to make sure my black levels are good as I find the Firstlight scopes a bit small even at full size. I render a master to Cineform and bring it into TMPEG without any filters applied to downconvert to DVD. Final product looks good and reflects what I saw during color correction.

The exception I have found with Vegas and Cineform is when using interfacing with Adobe products. If you render a Cineform file out of Vegas where Vegas has to recompress (even if it's with a null effect) then Vegas will screw up the color space for After Effects and Premiere. The file will look fine in Vegas and even in TMPEG 4 (not sure about 5). But in AE and PR the black levels will jump 7.5IRE.

NOTE 1: In Premiere the waveform scope will show the same black levels on the Vegas rendered Cineform file as it did in Vegas but the file will be noticably lighter. In AE if you have the "Test Gear" scope plugin from Sythentic Aperture it will reflect the 7.5 IRE level jump.

NOTE 2: This does not happen if you smart render a Cineform file out of Vegas that was originally converted in HD Link and bring it into AE or PR. This is a major bug but workable if you limit yourself to smart renders or work in Vegas only.

[Marc Salvatore]

Gerald,

If you can upload a sample of the file you edited in Vegas (before TMPEG conversion) I'd be happy to look at it on my scopes. Make sure it has some black in it.

Marc

[Gerald Webb]

Mervan, noted, thanks. I was thrown by the difference in the scopes.
Marc,
So if I converted all my clips in to Cineform in Vegas , not HD Link......
Does that mean that after cutting and then forcing a full render out of Vegas by adding a convolution kernal as suggested by Cineform to create a completely new Cineform file, Im getting two shifts in levels?

How would you suggest workflow for a multi camera shoot?
On two jobs now, I tried just converting the folders of raw files through HD Link and failed dismally, Vegas just kept crashing, only way I got it sorted was to sync the source files in Vegas and render out each cam to Cineform on its own track, thus having 7 large Cineform files rather than about 35.
Would I be better to do this in another NLE, Is Vegas the problem or Adobe?

Im getting some good results now but I'm kind of getting the feeling that it shouldnt be this hard with so many "gotchas" to find and overcome.
I might take you up on that offer Marc, Ill upload a short clip. Ill send a link.
cheers

[Marc Salvatore]

Gerald, I have not heard about adding the convolution kernal but the rule of thumb is that if you render any Cineform files in Vegas (other than smart rendering where no compression is applied) then do not use those files in After Effects or Premiere because your black levels will jump. As far TMPEG 4 I do not have a problem with the black levels jumping when rendering a file to Cineform from Vegas. Don't know if this is a problem in TMPEG 5. I've filed a ticket about the issue with Sony but I'm not holding my breath.

I have had problems as well converting long files in HDLink. It does not appear to be up to the task and when it happens I also convert in Vegas. As long as you stay in Vegas throughout the workflow and stay away from Adobe it should be ok save your TMPEG problem which I am not experiencing using TMPEG 4.

On the other note I'm still wondering if this could be a calibration issue where you may color correcting based on your secondary preview in Vegas which may not be accurate and when you play your DVD it reflects the inaccuracy. I guess one way to test it would be to convert the same Cineform HD file in Vegas to DVD and see if it looks dramatically different than the TMPEG result.