Yellowing showing on white areas?

Hi All,

I am new to shotcut and started to use it last week, I am enjoying it so far and really loving its powerful features but I am having a little issue I don’t understand and I can’t find anyone else talking about.

I have loads of old VHS family videos from when I was a child that I am in the process of digitising and I plan to do the clean-up and editing of them all in Shotcut, but from doing a little test yesterday I found a strange issue that I was hoping someone might know the answer to before I really get into the editing process as it’s a bit of a showstopper for what I want to do.

Firstly - I am capturing the VHS videos outside of shortcut as 720p mpeg2 files, no issues here.

I open Shotcut and make a project, I drag my mpeg2 file into the playlist and then onto the time line for editing.

At this point, everything looks perfectly fine and I can playback the videos and they look as I expect them to.

Things seem to go wrong as soon as I apply ANY filter?

As they are old VHS videos I want to colour grade and also crop to remove the wobbly and black edges, this is my overall intention for filters, but as soon as I apply any of the filters, and I does not matter what filter I apply, I have tested just adding others one at a time and playing back the videos.

So what happens?

As this is old camera footage, some part of the video is very white in certain areas and overexposed and its these parts that start to acquire a yellow/green (however you see it) tinge and that continues in random white bits throughout the video and to the exported version if I export it.

I have tried exporting the video via shotcut to mp4 before I apply any filters and this looks fine and saves fine, but as soon as I add the newly saved mp4 to shotcut in a new project and start to apply ANY filter, the yellow/green parts on white return?

Does anyone have any ideas what the cause is?

I attached a screenshot so you can see what I mean :slight_smile:

Thanks to anyone who can help me :slight_smile:

Take a look at a clip’s Properties. What is color range set to? Open View > Scopes > Video Waveform. Go to a frame with a fair amount of white. Post a screenshot that shows these all together.

Hey, thanks for looking > is this what you wanted to see?

this was the test version that I exported right away as mp4 and then tested again with.

Ah yes, a change of the “colour Range” to “Full (JPEG)” seems makes it go away instantly, very odd :slight_smile:

I suspect your clip is actually full range because in the first screenshot, in the scope, those areas near white look crushed. Many filters operate in RGB, and when a clip with limited range YUV is converted to RGB then anything over the limits is clamped or crushed. Something strange is happening in this area.

this is what it looks like if I make a new project and just drag it into the timeline and not try and add any filter

Now, you can clearly see the levels in the scope exceeding 100.

fantastic :slight_smile: thank you for your expertise, I really appreciate your time in helping me :slight_smile: keep up the great work the software is fantastic

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