MOV is the QuickTime movie format Apple introduced in 1991. Today it’s what iPhones, iPads and Macs record and export, and many cameras and screen recorders use it too. MOV was the basis for the MP4 standard, so the two formats share the same structure.
What’s inside a MOV
Like MP4, MOV is a container that holds separate video and audio streams. The codec inside matters more than the extension:
| Source | Video codec | Audio codec |
|---|---|---|
| iPhone, default “High Efficiency” setting | HEVC (H.265) | AAC |
| iPhone, “Most Compatible” setting | H.264 | AAC |
| Mac screen recordings | H.264 | AAC |
| Professional cameras and editing exports | Apple ProRes | PCM |
Why MOV videos sometimes won’t play
There are two separate problems, and they’re often confused:
- The container. Some apps, websites and devices simply don’t accept
.mov. Converting to MP4 fixes this, usually by copying the streams unchanged. - The codec. iPhone videos are usually HEVC. A PC without HEVC support plays the sound with a black picture, whatever the extension. Converting the video to H.264 fixes this.
A quick way to tell: if the video plays on one computer but not another, it’s usually the codec.
ProRes
ProRes is Apple’s professional editing codec. It keeps very high quality and is fast to edit, but files are huge, often over a gigabyte per minute. ProRes MOVs are meant for editing software rather than sharing; export a compressed MP4 from your editor when the edit is finished.
Live Photos
An iPhone Live Photo is a still image plus a short MOV clip of about three seconds. When Live Photos are copied to a computer, the clip appears as a separate .mov file next to the photo.
When to use MOV
Keep MOV for editing on a Mac and for working with Apple apps. Convert to MP4 when you share a video with people on other devices, upload it to a site that rejects MOV, or need it to play on Windows or Android without extra software.