Contrast Query - lift_gamma_gain vs frei0r.contrast0r


Shotcut is my joint favourite movie editor, along with Kdenlive. They both use the MLT framework, but I was wondering why Shotcut uses the lift_gamma_gain plugin to implement contrast rather than the frei0r.contrast0r plugin that Kdenlive uses? I’m just interested to know the reasoning behind the decision - I’m not complaining :slight_smile:

Many thanks

I don’t use “contrast” controls because I need separate control over black and white levels. Contrast affects both and I don’t care for/don’t use it.

As I recall, the decision was because I wanted to have greater parity between the CPU and GPU versions of this particular filter. There is no frei0r.contrast0r for Movit GPU processing, and Shotcut’s Contrast for GPU was implemented using movit.lift_gamma_gain. MLT “lift_gamma_gain” was created as a CPU version of the same Movit effect. Therefore, the CPU version of Shotcut Contrast chose to use it in the same manner.

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