What actually changes between MP4 and MOV
MOV is the QuickTime container, and it holds the same H.264 video and AAC audio that a standard MP4 does. So this conversion probes the file first and, in the normal case, copies the streams into a MOV without re-encoding anything: lossless, and finished in seconds. A real encode runs only as the fallback for unusual codecs.
The work happens on your own device, with nothing uploaded, and the output is written so playback can start immediately when the file streams.
- The MP4 streams are probed on your own device
- H.264 and AAC copy straight into the MOV container
- Unusual codecs fall back to a local re-encode