range option

Anything and everything to do with DCP-o-matic.
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doctor04
Posts: 3
Joined: Fri Sep 20, 2019 9:01 pm

range option

Post by doctor04 » Sun Oct 27, 2019 2:13 am

How to choose the range option. What is the difference between jpeg 0-255 and mpeg 16-235.

Carsten
Posts: 1462
Joined: Tue Apr 15, 2014 9:11 pm
Location: Germany

Re: range option

Post by Carsten » Sun Oct 27, 2019 1:40 pm

I wish Carl had put this into the color conversion dialog so it's not immediately visible ;-)

Image sources may differ in the range of valid color/brightness values, depending on where they came from. Normally, the underlying FFMPEG framework should deal with this correctly automatically, but, occasionally, manual intervention may be necessary.

Typical video files (MP4, MOV, AVI, MKV, etc.) should all be video level (16-235). Unless they come from an advanced video editor and the user has chosen to create them full range. The JPEG/MPEG designation there is a bit misleading and should probably be removed.

The problem here is that ultimately, we want to be able to have an option so we can override false range sources - but, the way it is now, it forces uneducated users to make a decision they may not understand.

Best is to let DCP-o-matic do the guessing. Just as with aspect ratio and color conversion, DCP-o-matic mostly does it right. Typically, one can verify the proper setting in the video waveform monitor. Some sources with flipped video range setting will show obvious lifted (grey) blacks, or crushed blacks.

- Carsten

carl
Site Admin
Posts: 1082
Joined: Thu Nov 14, 2013 2:53 pm

Re: range option

Post by carl » Mon Oct 28, 2019 11:03 am

I wish Carl had put this into the color conversion dialog so it's not immediately visible
I see what you mean. The question is, where does it go? If we put it in the colour conversion dialog don't we end up with menu options like
  • sRGB full range
  • sRGB video range
  • ...
?

Carsten
Posts: 1462
Joined: Tue Apr 15, 2014 9:11 pm
Location: Germany

Re: range option

Post by Carsten » Mon Oct 28, 2019 11:29 am

I guess I would 'preset' this to limited range for all video sources (or if flagged in the file), and full for still images. Then have an option to override to 'full' in color correction, making it a custom color preset if changed from default?

- Carsten

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