Convert MP4 to MOV
Wrap MP4 video in a QuickTime MOV container for Final Cut, iMovie and QuickTime Player. Streams are copied across, so nothing is re-compressed.
- Runs in your browser
- Files are never uploaded
- Free, no account
First use downloads the 10 MB video engine from this site. After that it is cached and works offline. It is WebAssembly served from onthisdevice.com — no third-party CDN — and your file is still processed entirely on your own device.
MP4 and MOV are closer than they look
Both formats are the same file structure with a different label on the front. Apple designed
QuickTime (.mov) in 1991; the MPEG group adopted it as the ISO base media file format and
built MP4 on top of it. Inside, both are a tree of boxes — ftyp, moov,
mdat — laid out identically. What differs is the brand recorded in the
ftyp box and the short list of codecs each one officially permits.
That is why this conversion is a copy, not a transcode. Every video and audio packet is written to the new file untouched, the index is rebuilt, and the output lands within a few kilobytes of the input. Nothing is re-compressed, so the picture is byte-for-byte what you started with.
When you actually need a MOV
- QuickTime Player on an older macOS refuses some MP4 files that it happily opens once they are re-wrapped.
- iMovie and Final Cut are stricter about brands and audio layouts than a player is; a re-wrap is often enough to make an import that was being rejected go through.
- Older Apple hardware and some broadcast tools expect the QuickTime brand specifically.
- Timecode and alpha-channel workflows live in MOV rather than MP4 — though those need a source that already carries them.
What re-wrapping cannot do
If Final Cut still rejects the clip after this, the problem is not the container: it is the codec. Apple’s editors prefer ProRes, an intra-frame format where each frame stands alone, because H.264 has to be decoded across a run of frames and that makes scrubbing expensive. Producing ProRes needs an encoder that is not available in a browser, so this page does not pretend to offer it. On a Mac, the free command line tools or Compressor will do that conversion; here you can at least confirm that the container is not what is standing in your way.
| Question | MP4 | MOV |
|---|---|---|
| Underlying structure | ISO base media file format | ISO base media file format |
| Typical codecs | H.264, HEVC, AAC | H.264, HEVC, ProRes, PCM, AAC |
| Plays on Windows out of the box | Yes | Not reliably |
| Plays on Apple devices | Yes | Yes |
| File size for the same footage | Baseline | Within a fraction of a percent |
| Is one “higher quality”? | No. Quality lives in the codec and the bitrate, never in the container. | |
Faststart is switched on
The index that says where every frame lives is written at the front of the output file rather
than the end. That is what -movflags +faststart does, and it means the file can
begin playing before it has fully loaded — useful if you ever put it on a web page, and
harmless otherwise. It costs one extra pass over the file at the end of the copy.
Going the other way
Converting a QuickTime file back to MP4 is the same operation in reverse and is covered by MOV to MP4. If you need a smaller file for sharing rather than a different container, compress video is the tool for that.
Questions
What is actually different between MP4 and MOV?
Very little. Both are built on the same ISO base media file format that Apple originally designed as QuickTime. MOV allows a few extra things — ProRes, timecode tracks, PCM audio — but for ordinary H.264 footage the two containers hold identical data with a different four-character brand.
Why does Final Cut or iMovie want MOV then?
Apple’s editors are fussier about the brand and the audio format than a player is. Re-wrapping as MOV is often enough to make an import work. If Final Cut still refuses the clip, the file needs a genuine transcode to ProRes, which needs a desktop encoder — we cannot do that here and will not pretend otherwise.
Does this change the video quality at all?
No. On the copy path every video and audio packet is written to the new container unchanged, so the picture is byte-for-byte the source. The file size stays within a few kilobytes of the original.
Is a MOV file bigger than an MP4?
Not meaningfully. Container overhead differs by a fraction of a percent. Anyone telling you MOV is “higher quality” is describing ProRes MOV files out of a camera, which are a different thing entirely from re-wrapped H.264.