FWIW common libraries like ffmpeg and what not can contain bugs which video files could potentially abuse and exploit.

Is that a common risk? Probably not. But image libraries have been known to have such exploits.

If TPB tells you to download a malicious MKV file, it might be specially crafted to exploit a vulnerability in your video player. For instance, VLC had a vulnerability in 2019: https://www.videolan.org/security/sa1901.html

The chances of an mkv or mp4 containing malware are not zero, but might as well be, imo. You're much more likely to encounter moviefilename.mkv.exe or moviefilename.zip which contains an executable of some kind. Basically traps to take advantage of dumbasses. If you even sort of know what you're doing using tpb for purely media is okay. Hypothetically, of course.

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