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 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. 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. Or you can add a music or subtitle track to your video without needing to encode. Everything is extremely fast because it does an almost direct data copy, fueled by the awesome ffmpeg which does all the grunt work.
If you want to support my continued work on LosslessCut, and want the advantage of a secure and simple installation process with automatic updates, consider getting it from your favorite store:
Unsupported files can still be converted to a supported format/codec from the `File` menu. (Try fastest variant first.) A low quality version of the file (without audio) will then be created and opened in the player. The cut/export operation will still be performed on the original file, so it will be lossless. This allows for potentially opening any file that ffmpeg is able to decode.
- Select the cut segment's start and end time by moving the time marker and then pressing <kbd>I</kbd> to set start time, and <kbd>O</kbd> to set end time.
- Note that the segments you select will be **preserved** and exported to a new file. You can change this behavior with the **Yin Yang** symbol ☯️, in which case it will instead **remove** all selected segments and export the parts between.
- Note also that start time will not be accurate, see [Known issues](#known-issues--limitations)
- *(optional)* If you want to add more than one segment, move to the desired start time and press <kbd>+</kbd>, then select the next segment start/end times with <kbd>I</kbd>/<kbd>O</kbd>.
- *(optional)* By default, audio, video and subtitle tracks from the input file will be cut and exported. Press the `Tracks` button to customise and/or add new tracks from other files.
- For best results you may need to trial and error with another output format (matroska takes nearly everything), change keyframe cut mode or disable some tracks, see known issues below.
Note: The original video file will not be modified. Instead it creates a lossless export to a new file in the same directory as the original file with from/to timestamps.
Note also that the cut is currently not precise around the cutpoints, so video before/after the nearest keyframe will be discarded. EXIF metadata is preserved.
- **Cutting times are not accurate!** Start cut time will be "rounded" to the nearest **previous** keyframe.
- Lossless cutting is not an exact science. For some codecs it just works. For others you may need to trial and error depending on the codec, keyframes etc to get the best cut. See [#330](https://github.com/mifi/lossless-cut/issues/330)
- Your mileage may vary when it comes to `Keyframe cut` vs `Normal cut`. You may need to try both, depending on the video. [ffmpeg](https://trac.ffmpeg.org/wiki/Seeking) also has documentation about these two seek/cut modes. `Keyframe cut` means `-ss`*before*`-i` and `Normal cut` means `-ss`*after*`-i`.
- When exporting you may lose some proprietary data tracks (like `tmcd`, `fdsc` and `gpmd` added by GoPro). These can be exported to separate files however
- Some codecs are not supported natively. There is partial support with low quality. You can convert to supported codec from the menu, see [#88](https://github.com/mifi/lossless-cut/issues/88)
- If you get an error when cutting or opening any kind of file under Windows, try to disable your anti-virus. See [#18](https://github.com/mifi/lossless-cut/issues/18)
- If you get an error on Linux like `FATAL:setuid_sandbox_host.cc(157)] The SUID sandbox helper binary was found, but is not configured correctly. Rather than run without sandboxing I'm aborting now.`, try to run it as `./lossless-cut --no-sandbox`. See #258
- If any other problem, check [Known issues](#known-issues--limitations), or please search for existing issues before you file an issue here on GitHub.
The CSV export/import function takes csv files with one cut segment on each line. Each line contains three columns: `segment start`, `segment end`, `label`.
This project is maintained by me alone. The project will always remain free and open source, but if it's useful for you, consider supporting me. :) It will give me extra motivation to improve it. Or even better [donate to ffmpeg](https://www.ffmpeg.org/donations.html) because they are doing the world a big favor 🙏
- App icon made by [Dimi Kazak](http://www.flaticon.com/authors/dimi-kazak "Dimi Kazak") from [www.flaticon.com](http://www.flaticon.com "Flaticon") is licensed by [CC 3.0 BY](http://creativecommons.org/licenses/by/3.0/ "Creative Commons BY 3.0")
