Checklist

• I'm reporting a feature request
• I've verified that I'm running yt-dlp version 2021.10.10
• I've searched the bugtracker for similar feature requests including closed ones
• I've read the opening an issue section in CONTRIBUTING.md
• I have given an appropriate title to the issue

Description

Please add a mechanism for detecting available features of FFmpeg in use. Features should include but are not limited to bit stream filters (bsfs).

A use case is to determine whether setts is available as a bsf in the FFmpegFixupTimestampPP class. The current code (committed to e36d50c) relies on the output string of ffmpeg -version for the availiablity of setts. This does not work in every situation. One reason is because the version string of FFmpeg is not necessarily in the form of dot-decimal notation (e.g. 4.4) but can be a commit hash (e.g. 6260c61).

In a shell script, the avalilabilty of setts in bsfs can be checked in the following way:

$ ffmpeg -hide_banner -bsfs | grep ^setts$
setts