Xilisoft Video Cutter is a dedicated utility developed by Xilisoft Corporation (now part of the greater Digiarty Software ecosystem). Unlike converters that re-encode video, a "smart cutter" identifies keyframes (I-frames) in compressed video formats like MP4, AVI, MOV, and MKV. By cutting only at these keyframes, the software avoids re-encoding, preserving the original quality of the video while completing cuts in seconds rather than hours.

: You can select and clip multiple segments from a single source file and merge them into a single output. Real-time Preview

Alternatives to consider (free or more feature-rich)