V18.12 BETA now available

Rules of Participation (Important)

  • Provide all feedback as a reply within this thread or as a GitHub Issue.
  • If using a GitHub issue, make sure you indicate the version.
  • You can reference other threads from this thread, but do not confuse others by opening new posts/threads.
  • Do not report about existing bugs that have not been indicated as fixed by this version.
  • The beta period is only going to last 7 - 14 days.
  • We are only interested in major regressions over recent versions (v18.08 and newer).
  • We are also interested in major bugs in new features and changes specific to this release.
  • There will only be another beta released if there is a critical problem that needs confirmation from testers after the fix.
  • The actual release may add some low risk fixes and additions (e.g. new filter) over the beta.


Get the beta release from this GitHub page that also includes the list of fixes, changes, and additions.
Linux AppImage, Snap, and Flatpak are not yet being offered in beta.

Thank You For Your Help!


There’s a small bug with the new mask filter.

The presets created in v 18.11 and earlier do not work with the new mask simple shape filter.

I just tried importing a png image and applying a mask: simple shape to it. It crashed every time. Haven’t had time to experiment with other imported media, eg jpgs.

Confirmed. Crashes with png but not jpg or bmp.

Yup, that’s what I’m getting… OK with jpgs.:unamused:

Works fine for Simple Shape on my end. Windows 10, 18.12 Beta

After a bit of further testing, I found:

  1. Applying the mask (simple filter) to a png on V1 when there is only one track causes a crash,


  1. Applying a the mask (simple filter) to a png on V2 when there are 2 pngs (on V1 and V2) is OK.

(Thinking about it, scenario 1 would be a bit silly since the purpose of the mask filter is to apply it to the top track of two tracks - but some users will try that and so I think it should still be addressed if possible.

This is no longer the primary use case of the Mask filters. Read the bottom of the release notes for full information. This crash is a really good find, and I am confident I can fix it.

I don’t see it in the release notes but is this version going to move to the new FFmpeg 4.1 release?

Not in this beta, unfortunately. I do not think it wise to include that change now. I will do it for v19.01.

Understood, on another note I’m seeing an improvement in performance compared to 18.11 on the order of ~20% in h264 export tests.

Is your test including a Text or Timer filter?

the text filter, I’m using “TheFireEscape” which @nwgat developed but replacing the default bundled shotcut version with the current beta to compare them.

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The new and improved Mask simple shape works brilliantly with a single track.:+1::+1:

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Formats look good for ‘Timer’ - thanks for fixing the mm:ss.ss format in this v18.12 beta version!

I fixed the crash on PNG with alpha channel for the release.

DaVinci Resolve has a strong following among film colorists for the ability to selectively darken, brighten, or change the colors of a scene. For instance, the colorist can put an oval over a person’s face and optionally motion-track the face in order to selectively lighten one face in a crowd, or lighten a face in an otherwise dark scene.

If I’m understanding the new Mask: Apply filter correctly, we can now mask color manipulation filters to do the same thing in Shotcut? If so, that’s a killer feature I never expected it to have in the short-term!

Actually, that was always available with the Mask filter. I’ve been playing around with this updated Mask feature and the “Mask: Simple Shape” is actually the same as the previous “Mask” filter. What the “Mask: Apply” feature does is allow you to do certain kinds of Mask effects without having to use a second video track.

So to use your example of selectively darken or brighten a spot what you previously had to do was create a second track and place a copy of the same clip above it. After selecting the second track’s clip you would apply the Mask filter then follow it up with the Brightness filter. After adjusting the brightness you would go back to the Mask filter then pick the shape, placement and even keyframes that you want to apply the spot.

Now with the “Mask: Apply” filter you can do it all in the same one track. So what you only have to do is go to the clip you want to selectively darken or brighten, first pick the “Mask: Simple Shape”, then pick the Brightness filter, make the adjustments on it and finally pick the “Mask: Apply” filter. So basically, in order to do certain Mask effects on one track the effect you want has to come in the middle of Mask: Simple Shape or Mask: From File and Mask: Apply filter.

So the order from up to down on the filters list to do a Mask effect on one track is:

  • Mask: Simple Shape filter OR Mask: From File filter
  • Effect filter
  • Mask: Apply filter

Very useful addition as it helps keeps things nice and tidy on the timeline plus speeds the workflow a bit more. I’ve also been experimenting with the Mask: From File filter and that’s very cool as well. It allows you to do things such as split screens much easier than before and does offer a second way of doing transitions although dissolves are not available and manual audio editing would have to be done in order to transition the audio as well. Still, this new Mask update really opens up the possibilities and makes Masking much easier than before. :slight_smile:

Another thing Austin, I tested this beta’s new Ut Video lossless preset that uses the yuv422p format. The file came out about 40% smaller than the previous Ut preset that used RGB and the rendering time was considerably less as well (about 60% faster). Is that your experience with the Ut lossless using yuv422p as well? I also tested out this beta’s UT preset from the Alpha channel preset and the file came out about 10% bigger than the previous Ut lossless preset with only slightly longer rendering time.

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I have not used the Mask filter before, so your rundown was very informative. It appears Shotcut has been closer to Resolve than I realized for quite a while. I guess where the Mask: Apply workflow comes in handy is when we need to brighten three people’s faces in one clip and we can’t stack multiple copies of the video because it would invade too many other tracks on the timeline. I like it.

As for Ut Video, yes, those are the same numbers I have seen. I am almost done with the proxy format report for the Proxy thread. I ran into two more bugs (in addition to the Ut Video color problems addressed earlier) that slowed down my testing: 1) zscale has an epic red shift problem when scaling down to low resolutions in 4:2:0 mode meaning I had to abandon it and redo every single test with libswscale; and 2) Shotcut had a bug where turning off a track’s visibility could darken the track beneath it, although this bug appears to be fixed according to the 18.12.15 release notes (I haven’t tested it yet). I used stacked tracks to analyze edge sharpness across proxies rendered with many different settings, and seeing the colors shift totally blew my confidence in my test methods until I realized it was a bug that could be worked around by putting a solid white color generator on V1 and leaving it always visible.