Transcode a Video
Pick a video, choose a target format — it's re-encoded in your browser, nothing is uploaded.
Transcode a video in your browser
Pick a video, choose a target format (MP4 or WebM), and get a re-encoded copy instantly. The transcode runs entirely in your browser with ffmpeg compiled to WebAssembly — your video is never uploaded to a server.
Formats
- MP4 — H.264 video + AAC audio with
+faststartfor quick playback. The most widely supported container across devices and browsers. - WebM — VP9 video + Opus audio. Open, royalty-free, and usually smaller than MP4 at a similar quality.
Tips
- Leave quality blank to use the default (75). Quality 1-100 maps to ffmpeg's CRF scale — higher quality means a larger file.
- Works offline once the page has loaded.
FAQ
What exactly does the quality slider control?
Quality 1-100 maps linearly onto ffmpeg's CRF scale (51 = worst, 0 = best): the default 75 corresponds to roughly CRF 13, and lower values give smaller files. It's a constant-quality setting, not a bitrate — complex footage produces bigger files at the same quality number.
How big a video can I transcode?
The input file and the transcoded output are each limited to 10 MiB. For larger clips, trim or compress the video first — encoding runs in a single browser tab, so short clips are the intended use.
Which codecs are used for MP4 and WebM?
MP4 uses H.264 video + AAC audio with +faststart (so playback can begin before the file finishes downloading); WebM uses VP9 video + Opus audio in constant-quality mode. Those are the two targets — there's no AVI/MKV/HEVC output.
How is this different from the video-compress tool?
video-transcode changes the container and codecs to your chosen target (MP4 or WebM), while video-compress re-encodes but keeps the input's original container. Use this one when you need a specific format, e.g. WebM for the open web.
Developer & Automation Access
Run it from the terminal
Same engine as this page, headless — via the gizza CLI:
gizza tool video-transcode 'url=https://example.com/input' 'format=mp4' 'quality=75'New to the CLI? Get gizza →
Open it by URL
Pre-fill and auto-run this tool with query parameters — the names match the API/CLI:
https://gizza.ai/tools/video-transcode/?url=https://example.com/input&format=mp4&quality=75Machine-readable descriptor: tool.json — title + parameters JSON Schema for agents.