I never recommend getting software this way, but I was desperate to find one of these last year myself as all of the other recommendations don't fit my workflow.
It seems the company that made this is no longer in business, but it is still available on cnet downloads.
https://download.cnet.com/Free-Video-to-GIF-Converter/3000-2186_4-76116200.html
Due to the nature of this type of share/free/trialware site, I highly recommend that you extract the resulting zip file download and upload the installer to virus total to make sure it matches this.
https://www.virustotal.com/gui/file...905f07fae11635dc33f1d7dcd58d0d51a37/detection
Also it is a good idea to have a realtime anti-virus running anytime you are installing/using unknown software.
It will try to open your browser on install, and it is trying to take you to their defunct website, just close your browser and don't bother using the help link in the program because it does the same thing. I have been using this for about a year and no virus scan has flagged it and I have not detected unusual network activity.
Judging by the files it drops, and processes running as it is doing the conversion, this is just a GUI interface for doing some FFMPEG magic. What I really like about this one is that it allows you to select individual frames to drop to help reduce file size of the final GIF without compression making for higher quality final gif.
With this being a very simple program, you should create a short clip of the scene you want to use before trying to convert. 3 to 4 seconds is a good comprimise. It only accepts a few file types, so you might need to convert short clips to AVI or mp4 before being able to use it. I know for sure it does not open webm files.