Glaximate Mask/Animation not in sync after export

I did an Animation Glaximate for Object tracking✅
I Shotcut Timeline, everithing looks good :white_check_mark:
after i export it, the Animation is not in sync with the video :exclamation::exclamation:

any clue? is it a Bug?
here is a screenshot with the 1st frame in Shotcut and the 1st frame in vlc player after the export


I did not reproduce it with version 24.04 on Windows. If you are going to post in the bug category you should make some attempt to follow the template that appears when starting a post to include basic information.

I manually tracked a subject similar to you. Then, to verify I placed the exported clip on a new top video track and changed its opacity to 50%. This will make it show a double image if there is an error, and it does not throughout:

Did you do something challenging such as:

  • Use variable frame rate video such as from a smart phone?
  • Change the video clip’s speed?
  • Change a frame rate somewhere?
  • Trim the starting time (trim in point) of the animation clip on Shotcut’s timeline?

The frames you showed are not even the same frame of video. Maybe you did some inaccurate manual tracking, showed a good tracking moment from the Shotcut screenshot, and a bad example from VLC. Even mine does that because I did not put a lot of work into making it accurate throughout, but as you can see there is still no double-image. That means the software did what it was told, but my skill or diligence is lacking:

Thank you very much for this rapid and details repley :grinning:

exuse me for my inacurate “emotional” post :confounded:

i did some investigations with my novice knowledge.

my workflow: (same for this test as for my original post)
filming go pro 11
transfer via usb to windows 10 PC
then i cut the gopro mp4 with a python script witch uses “ffmpeg” in the backgroud. it searches for highlight tags in the gopro video und splits the video to 10 secouns before the tag an 5 secounds after:
cmd =f"ffmpeg -y -i {inputfile} -ss {start} -to {end} -codec copy {outputfile}"
this could be an issue
then i import the files in shotcut (Shotcut version 24.04.28)
for this test, i put as you suggested, animation to track 1, cutted clip on track 2 with 50% transparency and the original on track 3.

now i draw the annimation on track 1 :white_check_mark:

in shutcut everiting seams OK

after exporting, i see a frame shift on (i think) the cutclip of track 2.
1 video (screenrecord og shotcut (everything seams ok)

2 video (export with frameshift)


Yes, I do think this is an issue. I am familiar with the technique, and even Shotcut includes it in Properties > menu > Extract Sub-clip…. But it creates something unreliable. It is like a miserable hacky attempt at editing, but it is provided to give people who accept the risks something. I never intended for people to use its output in a regular Shotcut editing project. After all, it is provided as an alternative to that! So, when people ask for this function, I have always recommended they try it, and if they do not like the result use Export.

Here are some things to try:

  • Turn off Export > Video > Parallel processing. Maybe that accounts for a difference between preview and export.
  • Use View > Resources > Convert to transcode all of the clips to an edit-friendly (intra-only) format. You should review the timing in the project afterward.
  • Do an experiment using the original GoPro videos trimmed manually.

Your related post to find highlight times

funny, this was also one of my posts :grinning:

this gopro higlights-spit-script works well. but i think i have to think on that, when i tray to overlay an annimation.

the upside for me, this way to split the gopro file is very fast. but, it does not rerender the video based on Key frame, it simply cuts it apart, and I presume, this is where those frame offset is comming from.

in my script i have an excluded “slow” version…
cmd = f"ffmpeg -accurate_seek -y -i {inputfile} -ss {start} -to {end} -c:v libx264 -c:a aac {outputfile}" ###### Slow