How to Convert MOV to MP4 on iPhone, Mac, Windows and Online

MOV is the QuickTime File Format that Apple introduced with QuickTime in 1991. When the MPEG group needed a file format for MPEG-4, it based the design on QuickTime, and the result became ISO/IEC 14496-14, the MP4 standard, published in 2003. Both files are built from the same kind of nested boxes (Apple calls them atoms), with a header that describes the tracks and a data area that holds the compressed frames. That shared ancestry is why many players open either extension, and why an MP4 and a MOV made from the same recording can be almost the same size.

The container is only the box, though. What decides whether a phone, laptop or TV can show the picture is the video codec stored inside it. A MOV from an iPhone can contain H.264 (also called AVC), HEVC (also called H.265) or, on Pro models, Apple ProRes. An MP4 usually contains H.264 or HEVC, and the audio in both is normally AAC. Two files with the same .mov extension can therefore behave completely differently: one plays everywhere, the other refuses to open on a Windows laptop. The extension change is the easy part; the codec change is what fixes playback, and it decides how long the conversion takes and whether any quality is lost.

Apple switched the iPhone camera to HEVC with iOS 11 in 2017, on the iPhone 7 and later. In Settings > Camera > Formats, the default is High Efficiency, which records HEVC video, and the alternative is Most Compatible, which records H.264. HEVC stores the same picture in roughly half the space, which is why Apple made it the default: a phone fills up far more slowly. The camera settings screen shows the difference plainly; at 4K and 30 fps it lists a minute of High Efficiency video at around 170 MB, against roughly 350 MB in Most Compatible.

The cost of that saving lands on whoever receives the clip. Windows 10 and 11 decode HEVC only after you install Microsoft's HEVC Video Extensions from the Microsoft Store, which is a paid add-on. Many Android phones support HEVC playback, but budget models, older smart TVs, car screens and some editing apps do not. Browsers depend on the graphics hardware and operating system underneath, so a clip that plays in Safari can show a black frame in another browser on the same machine. Since iPhone 12, clips can also be 10-bit HDR in Dolby Vision, which adds another layer that older players cannot handle.

H.264 has none of these gaps. It has been in every phone, browser, TV and editing program for well over a decade, and decoding it costs almost nothing on any device made since then. That is why the safe target for sharing is an MP4 with H.264 video and AAC audio. You give up some storage efficiency, but the person on the other end can press play without installing anything. If you edit on a Mac and only share with other Apple devices, HEVC is fine and you can skip the conversion.

None of the routes below cost money, and which one fits depends on where the clip is and how many you have. The cheapest fix is to stop the problem at the source: with Most Compatible set on the iPhone, every new clip is H.264, and the Photos app can hand it over in a widely readable form. The iPhone also has Settings > Photos > Transfer to Mac or PC; on Automatic, photos and videos copied over USB are converted to a compatible format, while Keep Originals copies the HEVC files untouched.

For clips you already have, a desktop app gives you the most control and no size limit. HandBrake is free and open source on Windows, macOS and Linux; its default Fast 1080p30 preset writes an MP4 with H.264 video and AAC audio. VLC can convert through Media > Convert / Save. For a quick one-off, you can convert MOV to MP4 in the browser: it accepts files up to 95 MB, up to 20 at a time, nothing to install, and the files are deleted 30 minutes after processing.

There are two very different operations behind the word convert. A remux copies the compressed video and audio streams out of the MOV and writes them into an MP4 container without touching a single frame. It finishes in seconds even for a long file, the quality is identical because nothing is decoded, and the size stays within a few kilobytes of the original. The catch is that a remux does not change the codec. An HEVC MOV remuxed to MP4 is still HEVC, so it still fails on the Windows laptop that could not play it before.

A re-encode decodes every frame and compresses it again with a new codec. It is the only way to turn HEVC or ProRes into H.264, and it is what HandBrake, VLC, QuickTime export and most online converters do, including the video converter on this site. Re-encoding always loses a little detail because the second encoder discards information again, but at sensible settings the difference is hard to see. With the Quality (CRF) scale used by H.264 encoders, 23 is the usual default and 18 is often described as visually close to lossless.

The command-line tool FFmpeg does a remux with ffmpeg -i clip.mov -c copy clip.mp4, where -c copy means copy the streams as they are. Use it when the MOV holds H.264 or HEVC with AAC audio and you only need the .mp4 extension, for example because an upload form lists MP4 only. ProRes and uncompressed PCM audio are not part of the MP4 specification, so those files need a re-encode. If the codec is the problem, re-encode; if only the extension is the problem, remux.

People are often surprised that the converted file is larger than the original. That is the HEVC trade in reverse: H.264 needs more bits to hold the same picture, so a clip re-encoded at the same resolution and similar quality typically grows to around 1.5 to 2 times its HEVC size. A ProRes MOV goes the other way and shrinks dramatically, because ProRes is an editing codec that keeps nearly all the detail and uses several gigabytes per minute at 4K. A clip that was already H.264 lands close to its original size, slightly bigger or smaller depending on the settings.

Resolution is the biggest lever if the result has to stay small. A 4K phone clip watched on a phone or a laptop rarely needs more than 1080p, and dropping to 1080p removes three quarters of the pixels, so the H.264 file often ends up smaller than the 4K HEVC original. Setting Resolution to 1080p and keeping Quality (CRF) at 23 is a sound default for sharing. If the file has to fit a fixed attachment limit, the bitrate math is covered in our guide to compressing video for Discord and email.

A video file carries two kinds of dates. The file system dates (created and modified) belong to the copy on your disk and change whenever the file is copied, downloaded or converted. The recording date lives inside the file, in the container's metadata, and iPhone clips also store the location there when location access is on for the Camera. Photo libraries such as Apple Photos and Google Photos sort by the internal date when they find one and fall back to the file date when they do not, which is why a converted clip sometimes jumps to today in your timeline.

Whether the internal date survives depends on the tool. A remux with FFmpeg keeps general metadata by default, and you can be explicit with -map_metadata 0. Re-encoders differ: some write the original creation time into the new file, others write the time of conversion, and some leave the field empty. Apple-specific keys, such as the location stored by the iPhone camera, are the most likely to be dropped, because they use QuickTime metadata entries that not every MP4 writer copies across. Keep the original MOV as the master and treat the MP4 as a sharing copy.

Most failed conversions fall into a few patterns, and each has a specific cause. Missing sound usually means the audio codec chosen for the output is not one the player supports, or the source has an unusual track, such as uncompressed PCM from a screen recorder or several tracks from a camera. Green or smeared frames point to a decoding problem, often hardware acceleration in the player or the converter struggling with 10-bit HDR HEVC. Washed-out color after conversion is the HDR version of the same issue: the converter drops Dolby Vision or HDR10 data and the result is shown as standard range without proper tone mapping.

Rotation is stored as a flag in the MOV header rather than in the pixels, so a tool that ignores the flag outputs a sideways or upside-down video; rotating the clip in the Photos app and saving it before converting avoids the problem. Screen recordings from an iPhone or from QuickTime on a Mac are recorded at a variable frame rate, which some editors and older players handle badly, letting the sound drift out of sync. Forcing a constant rate with the Frame rate option, at 30 or 60 fps, fixes it. For HEVC footage from drones or Android phones, the HEVC to MP4 page uses the same settings.