Cineform RAW to DPX at DVinfo.net

Agustin Goya · February 16th, 2008, 07:11 PM

Hi! I have some shots recorded with SI2k using cineform raw codec and need to convert them to DPX for grading on Scratch.
I think that CF2DPX.exe could may be a good option.
My question is:
Which format CF2DPX will export? 10bit log, 10bit lin,....?
If I use a log to lin Lut in Scratch, will the image be ok?
I do not care about RAW metadata cause color grade will be made entirely on scratch (from scratch ;-))

Am i doing right?
Will the DPX be in full quality?

Thanks in advance,
Agustin

David Newman · February 16th, 2008, 09:20 PM

I wrote a long reply but that disappeared, here is the short version.

SI is Log. CF2DPX preserves that. DPX is full quality. Scratch's Log to Linear LUT is not appropriate, likely a Cineon to Linear -- different curve. Doesn't matter, any good colorist can deal with this type of Log data. If you must convert to Linear (why?) the SI curve is
output = Log base 90 (input*89+1).

Agustin Goya · February 17th, 2008, 08:06 AM

Hi David! thanks for the info.
Should I compansate to a 2.2 gamma instead of 1.7 on scratch display lut?
Thanks again,
Agustin

David Newman · February 17th, 2008, 10:09 AM

Not necessarily. When finishing, it is only important to know what curve you are correcting to, so can't corrrectly filmout. As you are color correction you are modifying the source curve anyway, so it doesn't matter if you know accurately what the source is (in film you never really know the source curve) all the matters is the final result.

Agustin Goya · February 22nd, 2008, 10:19 PM

Hi David, I'm little confused.
I've exported to DPX usung CF2DPX and also did the adobe workflow mentioned in http://www.dvinfo.net/conf/showthread.php?t=94626 to compare results.
I think both dpx sequences (form After Effects and CF2DPX) should be equal, but they are not.
Am I mistaken?
I think that what i need is what is mentioned on the other post but with the advantages of command-line processing.

Quote:

You said:
"1) Camera has a custom log curve design optimium shadow detail through compression. See image Camera Log image.
2) Your DI suite doesn't know this curve.
3) You need to remap to a curve you DI suite knows.
4) With RAW metadata off in AE 32-bit mode, the output is photometerically linear, the SI curve has been removed for you. See image Converted to Linear.
5) Add the "Cineon Converter" filter in AE, and use the Linear to Log preset. The could also be done with the Cineon export, with the "standard" setting. One or the other not both.
6) Export to Cineon with the "Full Range". See image Remapped to Cineon Log.
7) In your DI, tell the software that you are using standard Cineon LOG 10-bit."

Is there any way to convert to standard log without After effects?
I though maybe iridas sequence publisher might be an option.

Thanks for your time.

David Newman · February 23rd, 2008, 09:45 AM

The DFX export from AE or CF2DPX will be the same if you don't apply extra curves. The only truly lossless DPX export is to not apply curves. If you are trying to take CineForm out with Cineon curves, yes they will look different. Also if use the 32-bit mode in AE, the CineForm RAW output will be linear, you don't want that for you export.

Sergio Sanchez · February 23rd, 2008, 10:20 PM

Agustin:

The reason im exporting with Cineon curves, is because tools like the Filmlight or Digital Fusion didnt recognize the files as log, if the source file is not a cineon. The same happened with the VFX guy`s the linear luts was not displaying properly with the SI log curve, so they had to export the files with the cin standard log curve applied.

In the case of the scratch i`ve done some tests with and without cineon curve applied, the same color correction. The material was transfered to film in a arrilaser so I used the arrilaser lut for scratch to calibrate the grading. The one with cineon curve applied worked better with the lut, because the ARRI LUT was set for standard LOG dpx files.

But David is right about saying that the important thing is the result, you can even work without the LUT`s and the lab will match the footage to the source you gave them. In my case the shots i delivered for the first data to film were completely linear and the footage looked very good, it was exactly the same as in my unbalanced LCD monitor, just with film grain. But in the first case i was using the After Effect color managment LUT`s to simulate the film out put, they are very accurate by the way.

The last works that i`ve been doing I`ve been using the standard cineon curves with gamma 1.0, that way I know that the LUT`s of the film printers, and film stocks are working 100%.

February 16th, 2008, 07:11 PM	#1
Agustin Goya New Boot Join Date: Feb 2008 Location: Argentina Posts: 6	Cineform RAW to DPX Hi! I have some shots recorded with SI2k using cineform raw codec and need to convert them to DPX for grading on Scratch. I think that CF2DPX.exe could may be a good option. My question is: Which format CF2DPX will export? 10bit log, 10bit lin,....? If I use a log to lin Lut in Scratch, will the image be ok? I do not care about RAW metadata cause color grade will be made entirely on scratch (from scratch ;-)) Am i doing right? Will the DPX be in full quality? Thanks in advance, Agustin

February 16th, 2008, 09:20 PM	#2
David Newman CTO, CineForm Inc. Join Date: Jul 2003 Location: Cardiff-by-the-Sea, California Posts: 8,095	I wrote a long reply but that disappeared, here is the short version. SI is Log. CF2DPX preserves that. DPX is full quality. Scratch's Log to Linear LUT is not appropriate, likely a Cineon to Linear -- different curve. Doesn't matter, any good colorist can deal with this type of Log data. If you must convert to Linear (why?) the SI curve is output = Log base 90 (input*89+1). __________________ David Newman -- web: www.gopro.com blog: cineform.blogspot.com -- twitter: twitter.com/David_Newman

February 17th, 2008, 10:09 AM	#4
David Newman CTO, CineForm Inc. Join Date: Jul 2003 Location: Cardiff-by-the-Sea, California Posts: 8,095	Not necessarily. When finishing, it is only important to know what curve you are correcting to, so can't corrrectly filmout. As you are color correction you are modifying the source curve anyway, so it doesn't matter if you know accurately what the source is (in film you never really know the source curve) all the matters is the final result. __________________ David Newman -- web: www.gopro.com blog: cineform.blogspot.com -- twitter: twitter.com/David_Newman

February 23rd, 2008, 09:45 AM	#6
David Newman CTO, CineForm Inc. Join Date: Jul 2003 Location: Cardiff-by-the-Sea, California Posts: 8,095	The DFX export from AE or CF2DPX will be the same if you don't apply extra curves. The only truly lossless DPX export is to not apply curves. If you are trying to take CineForm out with Cineon curves, yes they will look different. Also if use the 32-bit mode in AE, the CineForm RAW output will be linear, you don't want that for you export. __________________ David Newman -- web: www.gopro.com blog: cineform.blogspot.com -- twitter: twitter.com/David_Newman

February 17th, 2008, 08:06 AM	#3
Agustin Goya New Boot Join Date: Feb 2008 Location: Argentina Posts: 6	Hi David! thanks for the info. Should I compansate to a 2.2 gamma instead of 1.7 on scratch display lut? Thanks again, Agustin

February 23rd, 2008, 10:20 PM	#7
Sergio Sanchez Regular Crew Join Date: Feb 2007 Location: Mexico Posts: 176	Agustin: The reason im exporting with Cineon curves, is because tools like the Filmlight or Digital Fusion didnt recognize the files as log, if the source file is not a cineon. The same happened with the VFX guy`s the linear luts was not displaying properly with the SI log curve, so they had to export the files with the cin standard log curve applied. In the case of the scratch i`ve done some tests with and without cineon curve applied, the same color correction. The material was transfered to film in a arrilaser so I used the arrilaser lut for scratch to calibrate the grading. The one with cineon curve applied worked better with the lut, because the ARRI LUT was set for standard LOG dpx files. But David is right about saying that the important thing is the result, you can even work without the LUT`s and the lab will match the footage to the source you gave them. In my case the shots i delivered for the first data to film were completely linear and the footage looked very good, it was exactly the same as in my unbalanced LCD monitor, just with film grain. But in the first case i was using the After Effect color managment LUT`s to simulate the film out put, they are very accurate by the way. The last works that i`ve been doing I`ve been using the standard cineon curves with gamma 1.0, that way I know that the LUT`s of the film printers, and film stocks are working 100%.