r220114 missing xvidcore.dll
Using, avidemux_2.8.1 r220114_win64.exe.
If you install, if you manually unpack, no xvidcore.dll to be found (& so stated on program startup).
(Putting xvidcore.dll from 2.8 release into the 2.8.1 directory alleviates that startup message.)
Issue forwarded to project maintainer and should be fixed now, please try r220125.
Thank you for your report.