You can use mkvtoolnix, then go to -> output, and -> splitting -> by parts based on timestamps -> and there you can write the beginning and the end of the part you want extract (without spaces: like 1:02:07-1:04:40, for example).
problema muxando un file mkv (e aggiungendo un file di capitoli (xml))
Possibile errore: “The XML chapter file ‘nomedelfile.xml’ contains an error: ” is not a valid ccTLD country code.”
Soluzione: aggiungere, editando il file dei capitoli una “country”.