Video Trimmer and Clip Cutter failed, stalled, or looks wrong? Troubleshooting
Troubleshoot Video Trimmer and Clip Cutter by codec, container, parameters, memory, and browser while respecting quality and device boundaries.
Do not rename an extension to fake a format
An extension names a container, not a guaranteed video/audio codec. Keep the source and record size, duration, codec, dimensions, browser, and exact error. Never overwrite the only original repeatedly.
The easy-to-miss issue for this tool
For 00:10.500–00:25.000, variable frame rate and keyframes can shift the actual edge by a frame, so inspect the downloaded boundary.
Recommended troubleshooting order
- Load a very short, low-resolution known-good sample to confirm the tool starts.
- Check whether duration, video, audio, and dimensions are detected; missing metadata often means damage or an unsupported codec.
- Reduce duration, resolution, frame rate, or simultaneous file count.
- Close heavy tabs, retry in current desktop Chrome/Edge, and keep the page active.
- Reapply the workflow:
- Choose video and wait for its complete duration.
- Enter the start and end times.
- Set quality and audio bitrate, then start processing.
- Check the first frame, last frame, and audiovisual sync.
- If it still fails, use desktop FFmpeg or the producing application; do not claim browser support for that codec.
Parameter checks
- Start time
- End time
- Quality / CRF
- Audio bitrate
Common errors
Why is one frame extra or missing?
Timestamps and frame boundaries do not always align, especially in variable-frame-rate video.
Can trimming be lossless?
Keyframe copying works only for some files; this workflow may re-encode for timing and compatibility.
Is the file uploaded?
Media is read and transcoded in this browser tab and is not uploaded to FreeTool to perform the task.
Boundaries that cannot be bypassed
- No promise of lossless or exact frame cutting for every codec
- Variable-frame-rate boundaries can shift slightly
- Damaged indexes or unsupported codecs fail
Browser WASM lacks the full performance and codec set of native apps, and long video can take substantial time. A paused progress display does not mean server upload; processing is in the tab, but the browser can terminate it under memory pressure.
Privacy, rights, and open-source licenses
Media is read and transcoded in this browser tab and is not uploaded to FreeTool to perform the task. Troubleshooting images and outputs can still contain private, copyrighted, or hidden metadata. The ffmpeg.wasm wrapper is MIT and this release's FFmpeg core is GPL-2.0-or-later; source access and license notices must not be removed.