What does trimming a video mean?
Trimming keeps one continuous section of a video and discards everything before and after it. You define the section by a start point and a length. Nothing in the middle is changed, which makes it different from editing, where you might rearrange or alter footage.
This tool trims by copying the existing data rather than re-encoding it. That has two practical effects. It is generally quick compared with a full re-encode, and the picture quality of the kept section is not reduced by an extra compression pass. The trade-off is that video is stored in groups of frames, and a copy-based cut can only start cleanly at certain points, so the start may land slightly off from the exact second you typed.
When trimming is the right tool
Most people trim to remove the boring parts of a recording: the few seconds of fumbling before a screen capture starts, the walk back to the camera, or the long tail after the point has been made. It is also useful when a platform or email limit makes a full-length clip too large, since a shorter clip is a smaller file.
Trimming is also a good first step before other operations. If you plan to make an animation, cut the clip down first, then use GIF from Video so it only processes the moment you care about.
How to trim a video with this tool
- Drop your video onto the upload area, or click to select it.
- Enter Start (sec), the point in seconds where the clip should begin. The default is 0.
- Enter Duration (sec), how many seconds to keep from that point. The default is 5.
- Click Run. On first use the ffmpeg engine (roughly 30MB) is downloaded before processing begins.
- Check the preview, then click Download. The file is named after your original with "-trim" added and is saved as an MP4.
If you need to jump to 1 minute 30 seconds, enter 90. Both fields take plain seconds, not minutes and seconds.
Tips and limits
Because the cut copies the stream, expect the start to sit on a nearby keyframe rather than the exact frame. If a clip begins a moment earlier or later than you wanted, adjust the start by a second or so and run it again.
The output is always written as an MP4 file. Copying streams into MP4 works well for common formats, but some source types may not be compatible with that container, in which case you will see an error. Converting the source with the video converter first is a reasonable workaround.
There is no visual timeline, so find your timestamps in a player first. Everything is processed locally in your browser, so very large videos can be slow or run into memory limits.