Thumbnails for h.264/mp4 files

[qdraw]

Is your feature request related to a problem? Please describe.

(1) Generating thumbnails for video files (I have some .mp4 files for which it would be helpful if you could show the very first frame as a thumbnail).

Task:
Need to wrap ffmpeg as dependency:

https://ffbinaries.com/downloads
https://github.com/Vargol/ffmpeg-apple-arm64-build/tree/master

For the following architectures:

• linux-armhf (linux-arm)
• linux-arm64
• osx-64
• n/a - (osx-arm64)
• linux-64 (linux-x64)
• windows-64 (win-x64)

Add auto downloader in program with flag to preinclude

Describe the solution you'd like
Automatic thumbnails for video files

Describe alternatives you've considered
fallback image is present

Additional context