LosslessCut aims to be the ultimate cross platform ffmpeg GUI for extremely fast and lossless operations on video, audio, subtitle and other related files.
The main feature is lossless trimming and cutting of video and audio files, 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.
NOTE: After installing you may need to right click the application icon and then "Open" in order to bypass "Untrusted app" dialogs. This is because Microsoft requires a $300/year certificate just to remove this block (I'm not going to pay for that.) Alternatively try to google `windows how to run untrusted app`.
Unsupported files can still be remuxed (fast) or encoded (slow) to a friendly format/codec from the `File` menu. 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.*
- *(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)* If you want to re-merge all the selected segments to one file after cutting, toggle the button `Separate files` to `Merge cuts`.
- *(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 in the same directory as the original file with from/to timestamps. Note that the cut is currently not precise around the cutpoints, so video before/after the nearest keyframe will be discarded. EXIF metadata is preserved.
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
- **Cutting times are not accurate and will be "rounded" to the nearest keyframe.** In the future I plan on showing keyframes in the timecale, and eventually implement a "smart cut" feature that re-encodes only the part before the keyframe. See [#126](https://github.com/mifi/lossless-cut/issues/126)
- Your mileage may vary when it comes to `Keyframe cut` vs `Normal cut`. You may need to try both, depending on the video. See [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
- H265 is not supported natively. There is partial support with very low FPS and no audio preview. Alternatively convert to friendly codec (slow) 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, please check your anti-virus. It might be blocking execution of ffmpeg, 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
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")
