Contrast Preset malfunctions if above a threshold (50%?) value

What is your operating system?
Ubuntu Linux 18.04 (Kubuntu flavor) AMD64

What is your Shotcut version (see Help > About Shotcut)? Is it 32-bit?
21.02.27 64-bit
Shotcut 201128 linux-x86_64.AppImage

Can you repeat the problem? If so, what are the steps?


If a Preset is added to the Contrast filter with a value above 50%, when the Preset is recalled, an image like this…

…becomes this…


Also, after recalling the filter, when the time is advanced by as little as one frame, the indicated value jumps from the preset value to “100%”, although the image display is not the same as appears when 100% contrast is set manually.

Other filters , and their presets, function normally.

Presets for Contrast appear to function properly if the value is less than 50%

A demo video is available.

On 20.09.27 osx the bug exists even for values below 50%.

I only discovered a Preset that appeared normally while making the second cut (shown above; the first cut recorded the wrong monitor), so the “below 50%” was a guess I made on-the-fly as I observed “some work, some do not” for the first time, based upon the Default for Contrast being 50%.

This is fixed for the next version 21.04