Using WSL to cross compile FFmpeg - obsproject/obs-deps GitHub Wiki
Important Note
When trying to use the FFmpeg build scripts within a Windows Subsystem for Linux (WSL) environment, please ensure that the obs-deps git checkout was done within the WSL environment.
The zsh-based scripts expect a normal Unix-based file system (with symlink functionality) - as Windows/NTFS does not have file system support for a similar kind of symbolic link, the aliased script for building FFmpeg will not resolve correctly.
Meson and Ubuntu 20.04 LTS
At the time of writing, 20.04 ships with Meson 0.53.2 (early 2020). This relelease is too out of date for use with the cross-compilation scripts. Ubuntu 22.04 LTS however has a fairly up to date version, which is compatible (0.61.2).
In order for the scripts to work, you'll either need to manually update meson on 20.04, or upgrade to 22.04.