navilor

_,,,^..^,,,_ said:

navilor, welcome aboard!

 Thank you _,,,^..^,,,_.

I have been complaining about color grading for years and just stumbled upon this thread. This is my first post here.

I do a lot of encoding to create streaming video to deliver to my Roku via the channel Roksbox off of my nginx server in a FreeBSD jail. I have been in the process of reversing color grading for years and am really starting to get the hang of it.

At first I thought that color grading was limited to the high, mid, and low method however a few movies threw me for a loop. Alien, Aliens, the Transformers series, The Great Escape, Tron, Tron Legacy, and the Last Starfighter are just a few.

The tools that I use are:
DVDFab9
Sony Vegas to import the MPEG-TS stream if it is not VC1.
FFmpeg script to convert the MPEG-TS stream to H.264 video with stereo AAC audio in an MP4 container if Vegas rejects it. I do not do surround sound.
FFmpeg script to convert the audio if Sony Vegas rejects it.
FFmpeg script to convert the Sony Vegas output to meet streaming requirements in conjunction with Sox to fix the audio because my hearing sucks badly.

I tried DaVinci Resolve however the interface was wonky to me.

My method is to import the video into Sony Vegas (the consumer version), use NeatVideo when appropriate, use Color Corrector, and use the free plugin AAV ColorLab. On occasion I will need to adjust levels to fix things like The Great Escape and a few scenes in Alien to bring back the eggs in the cavern and the detail in the room with the huge gun.

I now have the beginning of a clue on this that I would like to share what I have learned so far. Feedback is always appreciated.

1) Teal & Orange has changed a bit and is more Cyan and Orange. To reverse this I go to the Cyan setting in AAV ColorLab and skew it -33 towards blue. In The Fifth element this fixes the scene of the Diva singing her opera song. If you look at the color of the planet behind her it doesn't look right. Skewing cyan towards blue turns white back to white and blue back to blue.

2) I first thought that every scene was modified differently until I realized that almost every movie that has been color graded uses one setting across the entire movie. If cyan appears to be modified in one scene only (the Diva scene above) it will also be modified on other scenes (the hallway outside of Bruce Willis' apartment for example). Skewing blue to cyan doesn't make a difference if there is no blue in a scene.

3) Decreasing the saturation of Red and Yellow fixes the orange grading. Take for example the Blu-ray for Transformers 3:

AAV Color Lab
* Red saturation reduced to 75 percent and Lightness upped to 120.
* Green untouched.
* Blue untouched.
* Cyan skewed to -33, Saturation lowered to 33, Lightness increased to 125.
* Magenta untouched.
* Yellow saturation reduced to 50 percent.

Color Corrector
* Low angle 285
* Low magnitude 0.100
* Mid angle 60
* Mid magnitude 0.100
* High settings untouched.

4) Fixing white balance globally is a bad idea. Same thing with color balance. I've learned those two lessons the hard way.

The Blu-ray Tron Legacy, after it was color corrected, turned into a mostly black and white movie by merely modifying cyan as shown above while the Blu-ray Tron was graded in a similar manner as Transformers 3. Note that they used color film for the real world in Tron and black and white film for everything in the computer. This means that there are two separate noise profiles to work with. The actors faces and costumes should be gray with the appropriate red or blue lines when they are in the computer.

One gripe that I have is that I cannot use older DVD movies as a reference as just about everything since 1998 or so have been subjected to some form of color grading where the most common one is the high, mid, and low modifications. There is no "one size fits all" method as it seems to be dependent not only on the studio but the person who did the color grading. Each Transformers movie is slightly different in its settings.

They even messed with The Blues Brothers Blu-ray which is one of my favorite movies. I took extra care with that one, but all it needed was a simple high, mid, low adjustment.

Note also that some DVD content is abysmal in its creation. Scott Pilgrim vs. the World appears to be at 29.970fps interlaced but that is only for the opening chapter. After that everything is 23.976fps progressive. The movie Moon with Sam Rockwell cannot make up its mind regarding frame rate.

Even then Blu-ray content can have issues such as not having their frames aligned properly, corrupt audio, and sometimes corrupt video. My FFmpeg script complains mightily during conversion on about twenty five percent of my content.

If anyone can find any problems with the above information please let me know as I am always open to learning, and the best way for me to learn is through failure.