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How to convert MOV to MP4 on a Mac

· 6 min read

MOV and MP4 are nearly the same container, so converting one to the other is usually a matter of rewrapping the video and audio streams without touching them, which takes seconds and loses nothing. On a Mac you can do that with a one-line ffmpeg command in Terminal or with a drag into a converter app; QuickTime Player, surprisingly, cannot, because its Export menu only writes MOV. The one decision that matters is whether to also re-encode HEVC video to H.264 for people on older devices, and this post covers when that is worth it.

Why MOV and MP4 are so alike

MP4 was standardized from Apple’s QuickTime file format, and the two share the same internal structure: a set of labeled atoms holding the streams and an index. The differences are at the edges. MOV can carry Apple-specific extras (ProRes video, timecode tracks, certain metadata) that MP4 does not define, and some players and websites simply refuse anything with a .mov extension regardless of what is inside.

Because the structures match, a MOV containing H.264 or HEVC video and AAC audio can be converted to MP4 by copying the streams into an MP4 wrapper. No decoding, no quality change. That describes nearly every MOV from an iPhone, a screen recording, or a camera. mov-vs-mp4-which-should-you-send covers when the distinction matters for the person receiving the file.

Why QuickTime Player is not the answer

QuickTime Player’s File menu has Export As, with options for 4K, 1080p, 720p, and audio only. Every one of those writes a .mov file, and every one re-encodes the video, which takes a long time and lowers quality slightly. There is no MP4 option. It is fine for trimming a clip or making a smaller MOV, but it does not convert to MP4, and that catches most people out.

The same applies to Photos: exporting a video from your library gives you a MOV.

Method one: remux with ffmpeg in Terminal

ffmpeg is the open-source tool behind most video converters. It is not preinstalled on a Mac; a package manager such as Homebrew installs it with a single command, or you can download a build from the ffmpeg site.

  1. Open Terminal.
  2. Type ffmpeg -i and drag the MOV file onto the Terminal window. Its path appears.
  3. Type -c copy -movflags +faststart and then a name for the output ending in .mp4, for example ~/Desktop/clip.mp4.
  4. Press Return. A multi-gigabyte file finishes in seconds because nothing is decoded.

-c copy copies every stream as is. -movflags +faststart moves the index to the front of the file so the MP4 starts playing immediately when streamed from a website or a message, which is a good default for anything you are going to share.

If ffmpeg refuses with a message about a codec not being supported in MP4, the MOV contains something MP4 cannot carry. Almost always that is ProRes video from a camera or an editing app, or PCM audio from a screen recording. In that case re-encode just the offending stream:

  • PCM audio: replace -c copy with -c:v copy -c:a aac -b:a 192k.
  • ProRes video: replace -c copy with -c:v libx264 -crf 18 -preset medium -c:a aac -b:a 192k. This is a full video re-encode and will take a while.

Method two: a drag into Manatee

Manatee converts MOV to MP4 without Terminal and without installing anything, because it bundles its own copy of ffmpeg:

  1. Open Manatee and choose Convert.
  2. Pick MP4 as the target.
  3. Drop the MOV file into the window, or drag it onto the menu bar icon. A folder of files works the same way; each one gets its own line in the job list with progress.
  4. The MP4 appears alongside the original. The MOV is never modified.

Manatee makes the codec decisions for you, so a ProRes MOV from a camera or a screen recording with PCM audio comes out as a standard MP4 that plays in QuickTime, on a phone, and in a browser. Everything runs on the Mac with nothing uploaded. It is a converter rather than an editor: trimming and cropping stay in QuickTime or iMovie, and if you need the file under a particular size for a message or an upload, that is its separate Shrink mode, where you name a size in megabytes.

Method three: just rename it (sometimes)

Because the containers are so similar, changing the extension from .mov to .mp4 works more often than it should. Select the file in Finder, press Return, change the extension, confirm. If the MOV held H.264 or HEVC video and AAC audio, most players will read the renamed file without complaint.

Why it is method three and not method one: a renamed file is not a real MP4. The header still says it is a QuickTime movie, and strict players, upload forms that inspect the file, and anything that checks the internal type will reject it or behave oddly. A MOV with ProRes or PCM inside will be broken after renaming, since those streams are not valid in MP4 at all. Use renaming as a quick test, not as a deliverable. If the renamed file plays, a proper remux will definitely work; run one of the methods above for the version you send.

Should you also convert HEVC to H.264?

iPhones record HEVC (H.265) by default in their High Efficiency setting. A remuxed MP4 keeps that HEVC video, and while every Mac and iPhone from the last several years plays it, older Windows machines, some Android phones, and many web players do not. If the recipient might be on one of those, re-encode to H.264, the codec that plays everywhere.

With ffmpeg: ffmpeg -i input.mov -c:v libx264 -crf 20 -preset medium -c:a aac -b:a 192k -movflags +faststart output.mp4. Expect a file roughly one and a half to two times the size of the HEVC original, and a few minutes of encoding per ten minutes of 4K video.

To avoid the question in future, set the iPhone to record H.264 from the start: Settings, then Camera, then Formats, then Most Compatible. The files are still MOV (the container does not change), but they convert with a remux every time. h-264-vs-hevc-which-one-your-mac-phone-and-recipients-can-open has the full compatibility picture.

Questions

Will converting MOV to MP4 lose quality?

Not if the streams are copied, which is what the remux does and what applies to nearly all MOVs. The picture is byte-for-byte identical. Quality changes only when you choose to re-encode (HEVC to H.264, ProRes to H.264), and at a sensible setting that change is not visible.

The MP4 is exactly the same size as the MOV. Did it work?

Yes. That is what a remux looks like. The container changed and the content did not. A much smaller MP4 would mean the video had been re-encoded.

The MOV will not open in QuickTime in the first place. Can I still convert it?

If another player opens it, yes; the MOV uses a codec QuickTime lacks and converting fixes that. If nothing opens it, the file is damaged rather than incompatible, and converting will fail. See how-to-fix-a-corrupted-mov-file-on-a-mac for the repair route; Manatee’s Repair mode handles that case and reports honestly whether the file was fixed, partly recovered, or not fixable.

Does the MP4 keep the date, location, and camera information?

A remux copies the metadata atoms along with the streams, so usually yes. If you want it gone before sharing, Manatee’s Clean mode strips GPS and camera metadata from the MP4 as a separate step.