dbermond [1] filed a deletion request for libsrt [2]:

This package is a duplicate of the 'srt' package that already exists on the [extra] repository.

It's the same package with a different name here on the AUR.

[1] https://aur.archlinux.org/account/dbermond/ [2] https://aur.archlinux.org/pkgbase/libsrt/