Convert M4V to MP4

Almost — they share the same container, but M4V can carry Apple-specific packaging that trips up some players and editors, and converting to a plain MP4 removes that friction. One limit: M4V files with FairPlay DRM (older iTunes purchases) can’t be converted, because the media is encrypted.

No. The transcode runs with WebCodecs on your device, so the video never leaves the browser — no account, no quota, no size limit. Chrome, Edge and Firefox work best; Safari’s video encoding is more limited.

If it is a plain M4V, yes. But an M4V bought or rented from the iTunes Store can carry Apple FairPlay DRM, and a DRM-protected file cannot be decoded or converted by any browser tool — that protection is the whole point of it. Home videos, exports and unprotected M4V files convert normally; only store-locked purchases are the exception, and those you would need to play through Apple own apps.

It is a re-encode to H.264, so technically a lossy step, but at the tool quality setting a single pass is visually the same as the source. Since M4V already holds H.264-family video in most cases, the picture you start with is already good; converting simply standardises the container and codec so the .mp4 is accepted where the .m4v extension was refused.

Sometimes that works, because M4V and MP4 are nearly the same container — but not reliably. If the file uses an Apple-specific feature or a player strictly checks the format, a renamed file still fails, and renaming does nothing for a DRM-protected file. A real transcode rewrites the video and audio into a standard H.264/AAC MP4, which is why it plays where a renamed file might not.