Best software for cutting mkv video part without re-encoding - loseless ?

[aaajan]

Hi everyone

Is there any good software to cut any part of mkv video without losing quality ?

Thank you !

[butterw]

There are several free lossless video cutters available (cut on keyframes without re-encoding).
Mkvtoolnix/mkvmerge is a muxing tool that supports all mkv features.

[abolibibelot]

MKVToolNix => “Output” tab => “Splitting” (several modes).

Avidemux indeed (in “copy” mode), but can be quirky, and development seems to be erratic, with useful features disappearing or becoming less convenient / reliable in newer versions (cf. this and this for instance). It's possible to use Avidemux to visually determine the cutting points, then copy the timecodes into MKVToolNix to do the actual cutting.

Also ffmpeg with the -ss and -t or -to options, although it's less accurate (according to the integrated help, -t only accepts a duration in seconds, for -ss and -to it's unclear – see below). For instance this should cut a 5min chunk of movie.mkv from 10:00 to 15:00 :

ffmpeg -i "movie.mkv" -ss 600 -t 300 -c copy "movie - cut.mkv"

From the integrated help (ffmpeg -h full) :

-t duration         record or transcode "duration" seconds of audio/video
-to time_stop       record or transcode stop time
-fs limit_size      set the limit file size in bytes
-ss time_off        set the start time offset