LosslessCut — The Swiss Army Knife of Lossless Video Editing

Introduction

LosslessCut is a cross-platform GUI tool for performing fast, lossless operations on video and audio files. Instead of re-encoding, it cuts at keyframe boundaries using FFmpeg, preserving the original quality while completing operations in seconds rather than minutes. It handles virtually any format that FFmpeg supports.

What LosslessCut Does

• Trims and cuts video and audio files without re-encoding
• Merges multiple files of the same codec into a single output
• Extracts individual streams (audio, video, subtitles) from containers
• Captures screenshots and thumbnail grids from video frames
• Batch-processes multiple files with saved segment configurations

Architecture Overview

LosslessCut is an Electron application that drives FFmpeg as its media processing backend. The playback engine uses Chromium's built-in media capabilities for preview, while actual cut operations invoke FFmpeg in stream-copy mode. The app parses keyframe data to show accurate cut points and warns users when cuts between keyframes would require re-encoding.

Self-Hosting & Configuration

• Install via Homebrew, Flatpak, or download portable binaries from GitHub
• Configure default output directory and filename template in settings
• Set preferred keyframe cut mode (nearest keyframe or exact with re-encode)
• Customize keyboard shortcuts for timeline navigation
• Choose output container format independently from the source

Key Features

• Near-instant operations by avoiding re-encoding
• Supports virtually all video and audio formats via FFmpeg
• Smart cut mode for frame-accurate cuts with minimal re-encoding
• Built-in media player with frame-by-frame navigation
• Segment label editor for organizing multiple cuts in a single session

Comparison with Similar Tools

• FFmpeg CLI — same engine but command-line only; LosslessCut provides visual timeline editing
• Shotcut/Kdenlive — full NLE editors that re-encode on export; LosslessCut is faster for simple cuts
• Avidemux — similar lossless cutting but older UI; LosslessCut has a more modern interface
• HandBrake — focused on transcoding; LosslessCut avoids re-encoding entirely

FAQ

Q: Why are my cuts slightly off from where I placed them? A: Lossless cutting can only split at keyframes. Enable smart cut mode for frame-accurate results at the cost of brief re-encoding near cut points.

Q: Can LosslessCut join files of different codecs? A: No. Merging requires all input files to share the same codec and parameters since no re-encoding is performed.

Q: Does it support subtitle extraction? A: Yes. LosslessCut can extract subtitle tracks as separate SRT or ASS files from any container format.

Q: Is there a CLI mode? A: LosslessCut is primarily a GUI application. For scripted workflows, use FFmpeg directly with similar stream-copy flags.

Sources

• https://github.com/mifi/lossless-cut
• https://losslesscut.app