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Rescreen / Free tools / M4A to MP4

M4A to MP4 converter

Drop an M4A here for an MP4 with the same sound, plus a picture if you want a video.

Convert an M4A file to MP4

Drop an M4A file here

or choose one from your device

Up to 2.0 GB. Stays on your device.

How to convert M4A to MP4

Three steps, all on this page.

  1. Choose your M4A

    Choose or drop an M4A file. The page reads what is inside and checks that this browser can convert it before anything starts.

  2. Convert to MP4

    Pick the options you want, then press Convert to MP4. Tracks that an MP4 can hold as they are get copied, which is near instant.

  3. Check and download

    The new file is opened again and checked against the original before it is offered. Play it in the preview, then download it.

What changes from M4A to MP4

  • M4A and MP4 are the same MPEG-4 format. MDN lists audio/mp4 with the extensions .mp4 and .m4a, and video/mp4 with .mp4, .m4v and .m4p: an M4A is an MPEG-4 file with sound only. Source
  • An MP4 can hold AAC, MP3, Opus or FLAC sound, and H.264, VP9 or AV1 video. MP4 comes from the ISO base media file format, which comes directly from Apple’s QuickTime format. Source
  • AAC is lossy. Apple Lossless (ALAC) is lossless, and among the major browsers only Safari plays it. Source
  • YouTube’s list of supported file formats is a list of video formats, with MPEG-4 and H.264 video among the preferred ones. Sound files appear only as tracks for its AudioSwap library. Source
  • YouTube recommends MP4 with AAC-LC sound at 48 kHz. It lists 24 to 60 frames a second as common frame rates and says other frame rates are also acceptable. Source
  • iMovie on a Mac exports with File › Share › File, where Format offers video and audio, or audio only. A photo in the timeline is made longer by dragging its edge away from its centre. Source
  • Clipchamp exports an MP4 at 480p, 720p, 1080p or 4K from the Export button at the top right of the editor; a project with sound only can also be exported as an .m4a. Source

M4A file

M4A (MP4, sound only)

  • Picturenone
  • SoundAAC or ALAC

MP4 file

MP4

  • PictureH.264
  • SoundAAC

Who converts M4A to MP4

Mostly people with a recording that needs to go somewhere that only takes video. A voice memo, a podcast episode, a song or a lecture recorded on an iPhone or Mac is an M4A, and YouTube, most social sites and many course and upload forms want an MP4 with a picture in it. Others just need the .mp4 name: a player, an editor or a form that lists MP4 and turns M4A away.

Are M4A and MP4 the same thing?

Nearly. Both are MPEG-4 files, built the same way inside. Apple started using .m4a for MPEG-4 files with sound only, so that music apps would know to open them, and .mp4 for files with a picture. An M4A from Voice Memos, the Music app or a podcast app nearly always holds AAC sound, the format Apple uses for downloads and recordings; now and then it holds Apple Lossless instead.

So converting an M4A to an MP4 does not need to touch the sound. This page copies the AAC across as it is, bit for bit, into a file named .mp4: it takes a fraction of a second and nothing is lost. Renaming the file by hand often works too. The difference is that this page writes a proper MP4, checks it opens, and tells you what is inside.

How to turn an M4A into a video with a picture

A sound-only MP4 is still a sound file. YouTube is a video site, and Instagram, TikTok, LinkedIn and most course platforms expect a picture too, so they turn a sound-only file away or show nothing. To post a voice memo, a podcast episode or a song, you need an MP4 with a video track. The usual answer is one still picture shown for the whole length: the cover art, the show’s logo, or a title card with the episode name.

After you choose the M4A, press Add a picture and pick a JPEG, PNG or WebP. The page makes an H.264 video of that picture, the video format YouTube prefers, and puts the M4A’s sound beside it unchanged. Because the picture never moves, it uses one frame a second, which keeps the file small and the conversion quick: a three-minute song takes under a second.

  • Size: the video takes the picture’s own shape, scaled down to fit 1920×1080 (or 1080×1920 for a tall picture). A 1280×720 picture stays 1280×720.
  • Shape: for YouTube, a 16:9 picture (1920×1080 or 1280×720) fills the player with no black bars. A square album cover works too; YouTube adds bars at the sides.
  • Text: keep words large and away from the edges, since players and phones crop or cover the corners.
  • Sound: AAC is copied as it is, so it keeps all its quality. Apple Lossless is decoded and saved as AAC, which YouTube recommends.

How big the MP4 will be

Without a picture, the MP4 is the size of the M4A, give or take a few hundred bytes. A still picture adds little, because after the first frame nothing changes: under 1 MB for a three-minute song.

MP4 made3:00 song (4.0 MB)1:00 voice memo (483 KB)
Sound only4.0 MB in 0.04 s483 KB in 0.01 s
With a 1280×720 picture4.8 MB in 0.6 s699 KB in 0.3 s
With a 3000×3000 photo (becomes 1080×1080)—697 KB in 0.3 s
The song is three minutes of 44,100 Hz stereo test music as a 256 kbps AAC M4A, and the voice memo one minute of 48,000 Hz mono AAC at 64 kbps, both made with ffmpeg 7.1. Converted with this page in Chrome 155 on an M1 MacBook Pro. With the 1280×720 picture, Safari 27.0 made a 4.9 MB song in 0.5 s and Firefox 157 a 5.0 MB song in 0.6 s. Every MP4 came out the length of the original.

How to open an M4A file

You may not need to convert at all. An M4A opens in the Music app and QuickTime Player on a Mac, in the Files app on an iPhone, in Media Player on Windows 11, in VLC on any computer, and in Chrome, Edge, Firefox and Safari: drag it into a browser tab and it plays. If one of those is all you need, keep the M4A. Convert when the place it is going asks for MP4, or for a video.

When not to convert

Do not convert in the hope of better sound. The AAC is copied as it is, so the MP4 sounds exactly like the M4A. Apple Lossless saved as AAC is a very good copy, not an exact one; if you need the lossless sound in another format, make a WAV with the M4A to WAV converter instead.

If the place you are uploading to takes sound files, an MP4 adds nothing. Podcast hosts, transcription services and most editors take M4A as it is, and Spotify for Creators takes it too. For an MP3, the format nearly every device plays, use the M4A to MP3 converter.

A still picture is not a music video. If you want photos that change, captions timed to the words, or a waveform that moves, use iMovie or Clipchamp below.

Other ways to convert M4A to MP4

Rename the file Any computer

  1. Change the end of the file name from .m4a to .mp4. On a Mac, turn on Finder › Settings › Advanced › Show all filename extensions first; on Windows, tick File name extensions on File Explorer’s View menu.
  2. Confirm when asked whether to use .mp4.

Works for most players and forms, because the inside is already MPEG-4. It adds no picture, so it does not help with YouTube.

iMovie Mac, iPhone or iPad

  1. Create a new movie and import the M4A and a picture.
  2. Drag the picture into the timeline, then drag the M4A below it.
  3. Drag the picture’s right edge until it is as long as the sound.
  4. Choose File › Share › File, keep Format on video and audio, choose a resolution, click Next, and save.

Free on Apple devices, and you can use several photos, titles and transitions. More steps for a single picture.

Clipchamp Windows, or any computer in a browser

  1. Start a new video and add the M4A and a picture to your media.
  2. Drag both to the timeline and stretch the picture to the length of the sound.
  3. Click Export at the top right and choose 720p or 1080p.

Comes with Windows 11, and adds text, waveforms and stock footage. It needs a Microsoft account.

ffmpeg Any computer, from the command line

  1. Install ffmpeg (on a Mac with Homebrew: brew install ffmpeg).
  2. For a sound-only MP4, run ffmpeg -i input.m4a -c copy output.mp4.
  3. For a video with a picture, run ffmpeg -loop 1 -framerate 1 -i cover.jpg -i input.m4a -vf "scale=trunc(iw/2)*2:trunc(ih/2)*2" -c:v libx264 -tune stillimage -pix_fmt yuv420p -c:a copy -shortest output.mp4.

The same result as this page, and the quickest way through a folder of episodes.

Frequently asked questions

How do I change an M4A file to MP4?

Drop the M4A on the converter at the top of this page and press Convert to MP4. Add a picture first if it is going to YouTube or a social site. It is free, with no sign-up or watermark, and runs in your browser.

Are M4A and MP4 the same thing?

They are the same MPEG-4 format. An M4A has sound only, usually AAC; an MP4 usually has a picture as well. That is why this page can copy the sound across without changing it.

How can I convert an M4A file to a video with an image?

Choose the M4A here, press Add a picture and pick the image, then convert. The MP4 shows the picture for the whole length with the M4A’s sound, ready for YouTube. iMovie, Clipchamp and ffmpeg can do the same.

How do I open an M4A file?

Double-click it: the Music app or QuickTime Player opens it on a Mac, Media Player on Windows 11, and VLC on any computer. It also plays if you drag it into a Chrome, Edge, Firefox or Safari tab.

How do I change an audio file to MP4?

For an M4A, use this page. Any sound file becomes a YouTube-ready MP4 the same way: a video track with a still picture next to the sound. iMovie, Clipchamp and ffmpeg take MP3 and WAV as well.

What is the best app to convert files to MP4?

For one file, a browser converter like this one is quickest and installs nothing. For a video with several pictures and titles, iMovie or Clipchamp. For a folder of files, ffmpeg. Prefer one that copies the sound rather than re-encoding it.

Why will YouTube not take my M4A?

YouTube is for video, and its upload formats are video formats. Make an MP4 with a picture on this page and upload that instead.

Is my file uploaded?

No. Your M4A is read, converted and checked on your own computer, so there is no upload and no queue. In Chrome and Edge on a computer files of any size work, written straight to a file you choose; in other browsers, files up to 2.0 GB. We count anonymous page views and whether a conversion worked; when one fails, the event also carries the step, your browser’s error and the file’s codecs, size and length in broad bands, never the file or its name. If a conversion fails you can choose to send us the file, which is deleted within 30 days. See the privacy policy.

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