Convert MP4, MOV, WebM & more — entirely in your browser. Nothing leaves your device.
Drop or select video/audio from your computer. The drop zone is replaced by a preview of your files. Nothing is uploaded.
Wait until the green “Engine ready” banner appears. Convert stays disabled until then. Pick MP4, MOV, MP3 or WAV and click Convert.
When conversion finishes, the green Download button appears. Save the file instantly to your device.
Pick a conversion — the output format is pre-selected, then drop your file.
No. 100% local processing with ffmpeg.wasm. No upload endpoint exists. Your video never leaves your device. Perfect for private files.
Free forever, no watermark, no account. We are supported by ads. Advertising and analytics remain disabled until you click Accept.
Best under 500 MB. Hard limit 1 GB for browser stability. For larger files, use Handbrake or Shutter Encoder desktop tools.
Video: MP4, MOV, MKV, WebM, AVI, FLV, WMV, M4V, 3GP, MPG, TS, MTS, MXF, GIF. Audio: MP3, WAV, AAC, OGG, FLAC, M4A, WMA, OPUS, AIFF, ALAC. Plus rotate, flip, compress, mute.
Yes — switch to the ✂️ Trim tab. Drag the blue handles on the filmstrip timeline (or type exact times) to select a part, press Delete to cut it out, repeat for more parts, then Save. Fast cut is instant (keyframe-snapped); Precise cut re-encodes frame-exact to MP4. Private, free, no watermark.
Engine is ~25 MB WASM, cached after first load. Second conversion starts instantly. We show progress bar.
Short guides on formats, privacy, and best practices. All conversions stay on your device.
Most online converters upload your files to a server. That risks leaks, logs, and third-party access. JSM-Video.com runs FFmpeg and canvas processing only in your browser — your media never leaves the device.
Read more →MP4 is the universal web and phone format. MOV is common from Apple devices. GIF is for short, silent loops. Learn when each makes sense and what quality settings to use.
Read more →Keep resolution reasonable, use MP4 with H.264 for video and MP3/AAC for audio. Browser conversion works best under a few hundred MB; very large files may need patience or a desktop tool.
Read more →Muting a video shouldn't mean re-encoding the whole file. Learn when a silent video actually helps — and how to strip audio instantly, without quality loss, entirely in your browser.
Read more →Extract audio from video privately for podcasts, ringtones, or music. Learn which bitrate to choose and how to do it 100% locally with ffmpeg.wasm - no server hears your audio.
Read more →iPhone videos save as MOV but play everywhere as MP4. Convert free and privately — usually instant, with zero quality loss.
Read more →Turn any MP4 or MOV clip into a shareable animated GIF for Discord, Slack, and social — free, private, no watermark.
Read more →Need to send via email, WhatsApp, or Discord? Learn how resolution, CRF, and audio removal get a 162MB video down to 25MB, 16MB, or 8MB without ugly quality loss.
Read more →JSM-Video.com stays free. If it helps, you can buy a coffee.
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