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.
### Re-encode only the audio track, leaving the video track
First export each track as individual files. Then use Handbrake or similar to re-encode the audio file. Then use the `Tools->Merge` in LosslessCut to merge the original video stream with your Handbrake output (or drag it into your original LosslessCut video to include it as a new track.)
If you want to support my continued work on LosslessCut, and you want the advantage of a secure and simple installation process with automatic updates, consider getting it from your favorite store:
They have exactly the same in-app features, except a few platform limitations. Apple doesn't allow opening VOB files with App Store apps. Apple App Store apps need to prompt for output directory. LosslessCut version in the App Stores lags a few versions behind the GitHub version, because I want to be sure that the new versions work perfectly before releasing in the App Stores. GitHub version can contain new, untested features and may contain some bugs. I consider the newest GitHub versions to be a public "beta" test.
Unsupported files can still be converted to a supported format/codec from the `File` menu. (Try the 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 all segments you create will be **preserved** and exported as new files. 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** segments.
- Note also that start times 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.
- *(optional)* In the right-hand segments panel, right click a segment for options, or drag-drop to reorder. Segments will appear in this order in the merged output.
- **When done, press the `Export` button (or <kbd>E</kbd>) to show an overview with export options.**
- *(optional)* adjust any export options
- **Then press `Export` again to confirm the export**
- 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).
- Press <kbd>H</kbd> to view help and all keyboard shortcuts.
- **Note:** The original video file will not be modified. Instead, a file is created file in the same directory as the original file with from/to timestamps in the file name.
- **Cutting times are not accurate!** Start cut time will be "rounded" to the nearest **previous** keyframe. This means that you often have **move the start cut time to few frames after** the desired 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 however be losslessly exported to separate files.
- EXIF/metadata can be preserved (see Export Options dialog), but it doesn't always output compliant files, so use it carefully.
- Some codecs are not supported natively. There is partial support with low quality playback and no audio. You can convert to a supported codec from the File menu, see [#88](https://github.com/mifi/lossless-cut/issues/88), however it may take some time.
- 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](https://github.com/mifi/lossless-cut/issues/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.
- If the app crashes immediately upon startup, check the permissions of your User and Temp folders, see [61](https://github.com/mifi/lossless-cut/issues/61).
- How to uninstall LosslessCut on Windows? There is no installer. Just delete the EXE file or containing folder. User files will be stored in your [appData](https://www.electronjs.org/docs/api/app#appgetpathname) folder.
- 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`.
-`segment start` and `segment end` are expressed in seconds or left empty. Empty `segment end` means segment ends at the duration of the video.
- Use comma `,` to separate the fields (**not** semicolon `;`)
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")
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