Most MOV files people want to convert come from an iPhone. Since iOS 11 (2017) iPhones record video in HEVC (H.265) by default to save space, and that is the real problem: a Windows PC without the HEVC extension, an older smart TV, a projector in a meeting room or an upload form at school shows a black screen, plays only the sound or rejects the file. Converting to MP4 with H.264 gives a file that virtually every device made in the last fifteen years can play.
MOV and MP4 are almost the same container
MP4 (ISO/IEC 14496-14, 2003) was built on the ISO base media file format, which in turn was derived from Apple's QuickTime format from 1991. Both are made of the same kind of nested boxes (atoms). That is why renaming video.mov to video.mp4 sometimes works: if the MOV already contains H.264 and AAC, many players accept it. If it contains HEVC, renaming changes nothing, because the decoder is still missing. What matters is the codec inside, not the extension.
| MOV (iPhone default) | MP4 from our converter | |
|---|---|---|
| Video codec | HEVC (H.265), with HDR often 10 bit | H.264, 8 bit, 4:2:0 |
| Audio | AAC, sometimes PCM from cameras | AAC 160 kbps |
| Windows, older TVs | often needs an extra codec | plays natively |
| Size | smaller for the same quality | usually larger than HEVC |
What our converter does
We always re-encode the video. The picture is encoded to H.264 at a constant quality setting comparable to common default encoder settings, the audio is encoded to AAC at 160 kbps. Then:
- Resolution and frame rate stay the same. A 4K video stays 4K, 60 fps stays 60 fps. Odd dimensions are rounded down to even numbers, which H.264 requires.
- Variable frame rate is kept. iPhones record with a slightly variable frame rate, especially in low light, and the MP4 keeps the original timestamps, so sound stays in sync.
- Portrait videos stay upright. The rotation flag is applied to the picture itself.
- Ready for the web. The index is written at the beginning of the file, so a browser can start playback before the whole file is downloaded.
- One video and one audio track. Extra tracks (a second audio track, Apple-specific metadata tracks) are dropped. General metadata such as the creation date is copied; do not rely on location data surviving.
Because we re-encode, our converter also handles MOV files with codecs that renaming or remuxing would not fix: HEVC, ProRes from editing software, Motion JPEG from older cameras, or PCM audio.
Common problems
iPhone video looks washed out or too dark after conversion
iPhone 12 and later can record HDR video (Dolby Vision, 10 bit HEVC). Our output is standard 8-bit H.264 and the HDR picture is not tone-mapped, so colours can look flatter than on the phone. For clips you know you will share, switch off HDR Video in the camera's recording settings, or choose Settings → Camera → Formats → Most Compatible, which records H.264 directly.
MOV is larger than 100 MB
An iPhone takes roughly 60 MB per minute in 1080p at 30 fps with HEVC and about 170 MB per minute in 4K. The free limit of 100 MB per file therefore means about a minute and a half of Full HD, or around half a minute of 4K. Trim the clip in the Photos app first, or use one of the alternatives below.
The MP4 is bigger than the MOV
Expected with HEVC sources. H.264 needs a higher bitrate than HEVC for similar quality, roughly up to twice as much. The upside is compatibility.
Audio drifts out of sync in an editing program
Some editors handle variable frame rate badly. Our MP4 keeps the variable timing, so if your editor needs constant frame rate, convert it locally to a constant frame rate, for example in HandBrake (Video → Constant Framerate) at 30 fps or the frame rate of your project.
Alternatives worth knowing
- On the iPhone: when you share a video by AirDrop, Messages or e-mail to a device that does not support HEVC, iOS may convert it to H.264 automatically. Importing into Windows over a cable can also convert, unless Photos is set to Keep Originals (Apple's explanation).
- On a Mac: QuickTime Player → File → Export As, and choose Greater Compatibility (H.264). The result is still a .mov file, but with H.264 inside.
- On Windows: to play HEVC without converting, install HEVC Video Extensions from the Microsoft Store (paid), or use VLC, which has the decoder built in.
Our converter is handy when you need a real H.264 file now, on a computer where you cannot install anything, or for a few clips at once (up to 10 files, results as a ZIP). Need only the sound of a video? See MP4 to MP3. Photos from the same iPhone in HEIC? See HEIC to JPG.
Background
QuickTime and its MOV container were introduced by Apple in 1991 (Library of Congress: QuickTime File Format). MP4 was standardised as ISO/IEC 14496-14 in 2003 (Library of Congress: MPEG-4 File Format). H.264 dates from 2003, its successor HEVC from 2013. HEVC saves a lot of space, but its licensing is complicated, which is one reason why support outside Apple devices is still patchy.