Or you can add a music or subtitle track to your video without needing to encode. It lets you quickly extract the good parts from your videos and discard many gigabytes of data without doing a slow re-encode and thereby losing quality.
The main feature is lossless trimming and cutting of video and audio files, which is great for saving space by rough-cutting your large video files taken from a video camera, GoPro, drone, etc. LosslessCut aims to be the ultimate cross platform ffmpeg GUI for extremely fast and lossless operations on video, audio, subtitle and other related media files. The swiss army knife of lossless video/audio editing
