Convert MOV to M4A

Nobody stands in a crowd holding a phone up because they wanted a shaky video of the back of someone’s head. They wanted the song. The same is true of a rehearsal recorded from the corner of a room, a recital filmed from four rows back, and a child finally playing a piece through without stopping — the camera was the recorder that happened to be in a pocket.

What you are left with is a video file where the picture is incidental and the sound is the entire content. Keeping it in Photos means it is filed as a moment; converting it to audio means it goes where music goes, plays with the screen off, and does not cost a gigabyte to keep. That is the job this page does.

The naming hides something simple. M4A is an MP4 file that happens to contain only audio, and MP4 was derived from Apple’s QuickTime format, which is what your MOV is. The three are close relatives, and the AAC audio your iPhone recorded is exactly the kind of audio an M4A is built to hold.

That closeness is why the M4A behaves so well on an Apple device. The Music app plays it, the Files app previews it, AirDrop carries it, and iCloud syncs it without anyone having to think about codecs. It is also why the conversion looks as if it should be instantaneous — and the next section is about why it is not.

It would be a convenient sentence to write that the audio is simply lifted out of the video and rewrapped. It is not true here. The engine is asked for a bitrate on every compressed audio target, and asking for a bitrate is what tells it to decode and re-encode rather than copy. So the AAC in the M4A is a new encode of the decoded AAC from the MOV.

That costs a real, if small, second generation of loss. On speech nobody will hear it. On music recorded by a phone in a loud room it is more than academic, because the first encode already had a hard job. The practical response is not to worry about it but to stop economising: use the high band, and the second pass has enough bits to be transparent.

They land at roughly 96, 128 and 192 kilobits a second. An hour of audio is therefore about 43 MB, 58 MB or 86 MB — all of them trivial next to the video, which for a minute of 1080p is around 65 MB on its own.

Because the sizes are all small, there is no real argument for economising on a recording you cared enough to make. Small is for a phone that is genuinely out of space; balanced is right for talking; high is the correct default for anything with music in it, and the difference between it and balanced is about half a megabyte a minute.

This works in Safari on the iPhone itself, which is the shortest route: open the page, tap to choose a file, pick the video from Photos, convert, and save the M4A into Files. The encode runs on the phone’s own processor.

The reason to mention it is that the alternative is worse in a specific way. Sending a video to a laptop to convert it means AirDrop or iCloud first, and moving a gigabyte around to end up with a forty-megabyte audio file is the wrong order of operations. Doing it on the phone also avoids handing the recording to anything else at all.

No tags at all: no title, no artist, no album, no date, no artwork. A library shows it under whatever the filename is, which for a phone video is a string of digits that means nothing to anybody.

Two minutes of preparation fixes it. Rename the file before you convert so the M4A inherits something readable, then add proper tags in the Music app or a tagging tool afterwards. Artwork is worth doing and easy: take a frame from the same MOV as a JPG and use that, so the recording looks like what it is instead of a grey note icon.

The video track is discarded deliberately — that is the whole point — and one audio track is written. A phone records exactly one, so for most files this is a non-issue, but a recording made with an external microphone through an adapter or an app that writes a second channel set may not behave as expected.

What is definitely lost alongside the picture is anything else the container held: the creation date, the location, any orientation information, and on a camera file the timecode track. The M4A is audio and nothing else. If the video is worth keeping as well, keep it — the conversion does not touch the original.

Up to 100 MB of source file. That is the constraint, and it is measured on the video rather than on the audio that comes out — an iPhone at 1080p writes about 65 MB a minute in High Efficiency mode, so roughly a minute and a half fits, and at 4K it is around thirty-five seconds.

For a whole concert that is not enough, and the honest answer is to trim first. The Photos app can shorten a clip without re-encoding it, so cutting to the song you actually want is quick and leaves a file that converts comfortably. A twenty-minute recording is a job for a desktop tool.

Reading the MOV, decoding the audio and encoding the M4A all happen in this tab, using the codecs the device already has. Nothing carrying the recording is sent anywhere, and you can watch the network tab during a conversion to see that.

It matters more than it sounds for this material. A rehearsal, a school hall, a friend’s living room, a paid gig somebody would rather was not circulating — these are recordings with other people in them, and uploading one to an unknown site to remove its picture is a strange thing to do on their behalf.