RaahUPSC · Video Tools
Trim Video
Keep only the part of a recording you need, such as one answer from a mock interview or a single slide walkthrough. Fast mode copies the streams untouched, so even long files are cut in seconds.
✓ No upload · ✓ No sign-up · ✓ No watermark
How to use Trim Video
- Choose a single video file; it loads into the preview player and the End box fills with the full duration.
- Scrub to the first frame you want and press Set start = current, then do the same for the end with Set end = current. Times can also be typed as seconds or hh:mm:ss.
- Leave Fast mode ticked for a quick, lossless cut, or untick it for a frame-accurate cut that re-encodes.
- Press Trim and download the file, saved with a -trimmed suffix.
Fast mode versus an exact cut
With Fast mode on, FFmpeg seeks to the start time and copies the existing video and audio packets without decoding them. Nothing is recompressed, so quality is identical to the original and the speed depends mainly on reading the file. The catch is that compressed video can only begin cleanly on a keyframe, which may sit a second or more before your chosen start.
Unticking Fast mode decodes and re-encodes the selected range with H.264 at CRF 23 and AAC audio, so the clip starts exactly where you asked. That takes much longer and loses a little quality, but it is the better choice when a precise first frame matters, for example clipping a single question from a recorded class.
Limitations
- Only one file can be trimmed at a time, and only one continuous section is kept per run.
- Exact (re-encode) mode uses H.264/AAC for MP4, MOV and MKV, VP8/Vorbis for WebM and MPEG-4/MP3 for AVI; other formats are saved as MP4. If Fast mode cannot cut a file, the tool retries once with a re-encode.
- In Fast mode the first moment may freeze briefly in some players.
Frequently asked questions
Why does my clip start a little before the time I set?
That is Fast mode snapping to the previous keyframe. Untick it to re-encode and get a frame-exact start.
Will trimming reduce quality?
Not in Fast mode, which copies the data as is. Exact mode re-encodes at CRF 23, which is visually close to the source for most footage.
Is the video sent anywhere for cutting?
The cut is made by FFmpeg running inside this browser tab. The file stays on your device the whole time.