MOV → MP4 with H.264 + AAC: plays everywhere, uploads to every platform.

From iPhone clip to form-friendly MP4, step by step

The MOV to MP4 converter re-encodes QuickTime files into H.264 video with AAC audio so they play and upload anywhere. A real run: you shot a 90-second recital clip on an iPhone and the school's portal rejects the .mov. Drop the file in — the first conversion also loads a one-time ~30 MB FFmpeg engine into the tab — and hit Convert. The tool decodes the clip (HEVC iPhone footage included), re-encodes at CRF 23 veryfast, the standard quality-versus-size setting for sharing, and hands you an .mp4 that Windows players, Android galleries and web forms all accept. Download it, upload it, close the tab; the original never left your machine.

Keep the tab open and in the foreground while it works — WebAssembly runs on your CPU, so burying the window can slow the encode, and closing the tab kills it. Big 4K files are the slow case: a five-minute clip can take noticeably longer than its own playback on an older laptop, so batch the small clips when you can and save the long ones for when you can wait. The engine loads once per browser, so your second and third conversions start faster than the first did.