usefulweb.site Video Cutter & Merger

Audio, video & images

Video Cutter & Merger

Trim video, remove a section or join clips: lossless copy or frame-exact re-encode.

MP4, MOV, MKV, WebM, AVI, MPEG-TS; max 250 MB and 20 minutes (in total when merging). Processed on our server in a private temporary folder that is deleted afterwards; the result can be downloaded for about 2 hours.

Seconds, mm:ss or hh:mm:ss.mmm.

Empty = to the end.

Try an example: Keep 0.2–0.8 s, frame-exact · Lossless cut from 0.5 s (keyframe copy) · Merge a clip with itself (lossless concat)

How it works

Cuts a video to a start and end time, removes a section from the middle, or joins up to 5 clips in order. Copy mode is fast and lossless but cuts on keyframes; exact mode re-encodes (H.264/AAC) for frame-accurate cuts. Clips with identical settings are joined losslessly with the concat demuxer, others are normalised to a common size and frame rate first.

  • Copy mode (-c copy) never re-encodes, so it is fast and lossless — but a video can only start on a keyframe. ffprobe lists the keyframes, and the tool reports where the cut really starts (the last keyframe at or before your start time). End points are exact to the frame.
  • Exact mode trims with the trim/atrim filters and re-encodes with libx264 (veryfast, CRF 20) and AAC 160 kbit/s, so every cut lands on the requested frame.
  • Remove a section: the parts before and after are kept and joined — by copying both parts and joining them with the concat demuxer (copy mode; the second part starts at a keyframe) or with the concat filter (exact mode).
  • Merge: if all clips share codec, resolution, pixel format, frame rate and audio settings they are joined with the concat demuxer without re-encoding. Otherwise each clip is scaled and padded to the first clip's size (max 1080p), set to its frame rate, given silent audio if it has none, and joined with the concat filter.

Sources

For scripts and AI agents

  • JSON API: POST https://videocuttermerger.usefulweb.site/api/v1/calculate (same calculation as this page)
  • Interface description: OpenAPI 3.1 · AI guide: llms.txt
  • MCP server (Streamable HTTP): https://videocuttermerger.usefulweb.site/mcp · tool name video_cutter_merger
Example request
curl -s -X POST https://videocuttermerger.usefulweb.site/api/v1/calculate \
  -H 'content-type: application/json' \
  -d '{…see OpenAPI examples…}'

Related tools

  • Universal Video Converter – Convert video to MP4, WebM, MOV or MKV: resize, set quality and fps, or remux losslessly.
  • Video Compressor – Shrink a video to a target size (two-pass) for e-mail, WhatsApp or Discord, or by quality.
  • Video to GIF Creator – Turn a video clip into a high-quality GIF or animated WebP with fps, width and dithering.
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