Problem with masking (custom mask track)

Help/How To
1

I have a textanimation made in a 3d programm that i want to lay over the footage. footage is in track 2, textani in track 1. I put mask (advanced from file) on textanimation to just let the text. But the mask is only working on half of the screen (or maybe 2/3) on the left part. Is this a bug or do i missed something?

I created the alpha mask video also in 3d program and made it a mp4 video in shotcut in advance.
I have the textani and the mask of it in singe image sequences. Not sure how this works as a mask.
Is that possible in shotcut?

how can i add a screenshot here?

thank you

2

Why not export text animation with alpha channel from the animation program ?

In the Mask:From File settings, did you select File Custom, and enter mask video location ?

3

You are either inverted or not communicating clearly. footage should be on V1 and textani on V2.

But the mask is only working on half of the screen (or maybe 2/3) on the left part.

It will depend on the the Threshold parameter unless you turn that off.

how can i add a screenshot here?

Try harder. There is a button and drag-n-drop. Your screenshot should show the Mask: From File filter as well as the timeline tracks.

4

Thanks for your quick answers!
Maybe i was not clear: the textani is on top of the footage, textani is named V2. As i understand the top layer plays first and lets only through what is masked out. Where do i find the threshold parameter?
Here is the screen. I tried it with masking and also Chroma key:

SC_masking_problem
SC_masking_problem1868×869 119 KB

As you can see, the textani is coming on top but the mask is only working on the left hand side.

thank you

5

If you have a separate file for the mask or alpha channel, you can use filter Mask: From File. It has the Threshold option. You can also choose whether to use the Brightness (luminance) or alpha channel of the file.

image
image1173×685 206 KB

But as @pdr noted, if your animation program can output a video with alpha, it is much easier and cleaner.

6

The 3d program outputs single images and also the alpha mask as single images. I also can generate a psd-file with alpha, but that won’t help i guess. The problem is the mask seems to work only on the left side - is that because of threshold? I would assume threshold does something similar like fade in but not only cover the left side (see image). I guess there is still something wrong, isn’t it?

I also tried the mask from file and it has exactly the same result - only working on left half.

I also generated a video for the textani and for the mask as mp4 with shotcut. But that is a cumbersome way. Can i also apply image sequence for textani and same for alpha channel? Or is it only working as video in mp4 format for example? Still not sure what is wrong here.

7

Problem solved!
Must have been my problem, obviosly i left the default rectangular mask in the settings, although i am quite sure i set the mask from file option (custom defined).
Here is how it should look like:

SC_masking_solved
SC_masking_solved1802×868 131 KB

Still the question: can i use image sequences for textani and alpha mask instead of video files?
That would make things even easier. But i dont see a simple way for that.

thank you all!

8

You can use an image sequence as a video clip: open the first image and click the checkbox in Properties. You can NOT use an image sequence for the Mask: From File mask source.

9

Thank you! I knew you can use an image sequence for the video, unfortunatly not for the mask itself. So i have to convert the image sequence for the mask first to a video and than use it as mask, which i did and now worked fine. I think a PNG can have transparency, maybe we can use that for the overlay including the mask? I think i could generate these PNG with my 3d application - that would help to make things easier :slight_smile:

10

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