Convert M4A to MP4
An M4A is already an MP4 file, but with sound only. This adds a picture, so video sites and social apps take it.
- Nothing is uploaded
- Works offline after first visit
- Open source
- No watermark · limit is your device’s memory; phones hold less
Turn an M4A, such as an iPhone voice memo, into an MP4 video with a picture, for YouTube or social apps. It is free, needs no account and adds no watermark, and your files are not uploaded: everything runs in your browser on your device. The size limit is your device’s memory, and phones hold less; give the page a short while after one visit to save itself for offline use, and then it works offline.
Done
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An M4A is an MP4 file that holds only sound. It is what the iPhone Voice Memos app saves, and what iTunes and Apple Music downloads without copy protection come as. Renaming it to .mp4 changes the name and nothing else: the file may open in a player, but YouTube, Instagram and TikTok still refuse it, because there is no picture in it.
Sites that “convert M4A to MP4” add that picture. This page does it on your device: drop the M4A with a photo, a cover or a logo, pick 16:9, square or 9:16, and an MP4 is written with the picture held for as long as the sound lasts. Without a picture, the video shows the name of the file on a plain background, which suits a voice memo.
Voice memos are often private: a meeting, a lecture, a family recording. Nothing is uploaded here, so they stay on the device. If you want the sound as an MP3 instead, use M4A to MP3; to go the other way and keep only the sound of a video, use Video to MP3.
How it works
- Drop the M4A and a picture, or tap to pick them. Drop several M4A files to make a video of each.
- Choose 16:9 for YouTube, square for feeds, or 9:16 for Shorts, Reels and TikTok.
- Convert, and upload the MP4 wherever you need it.
In your browser, not on a server
Your browser decodes the sound into plain samples, draws the picture once onto a canvas (fitted whole over a blurred copy, or the title on a plain colour), and its own WebCodecs encoders write that still frame once a second with the sound as AAC or Opus. Mediabunny (MPL-2.0) packs them into an MP4.
Compared with upload-based tools: Online MP3-to-video converters upload your music and cover art, add their logo to free videos, and cap the length. Unreleased tracks and private recordings stay private here: nothing leaves your device.
Verify it yourself. Give the page a short while after one visit to save itself for offline use, then turn off Wi-Fi or switch to airplane mode and run the tool again. Or open your browser's developer tools (F12, or Cmd-Option-I on a Mac), pick the Network tab, and watch it while you convert. The panel above does the same count for you.
Questions
Can I just rename .m4a to .mp4?
You can, and some players will still play the sound, but it is not a video. YouTube and social apps reject it because it has no picture. This page adds one, so the file they get is a real video.
Will it work on a song I bought from iTunes?
Only if it is free of copy protection. Older iTunes purchases came as protected .m4p files, whose sound is locked and cannot be read here. Songs you ripped yourself, voice memos and Apple Music-era downloads without protection are .m4a and work.
Is the sound re-encoded?
Yes. The M4A is decoded and the sound is written again as AAC (or Opus) with a target of up to 192 kbps, which is close to the original for voice and music. Video sites re-encode uploads anyway.
What does an iPhone Voice Memo look like as a video?
If you add no picture, the video shows the memo’s title on a plain background for the whole recording. Add a photo to show that instead.
I want to go from MP3 or WAV, not M4A.
MP3 to MP4 does the same job for MP3 files. The audio to video tool takes WAV, FLAC and OGG as well.
Is the file uploaded anywhere?
No. There is no server in this process. The page is a static file and the work is done by code running inside your browser tab. Give the page a short while after one visit to save itself for offline use; then you can turn off Wi-Fi and it still works.
More video and audio tools
Audio to video
Put a song, a podcast episode or a voice note on a still picture, ready for YouTube or social apps. Made on this device.
Compress audio
Shrink recordings, podcasts and songs to send or store. Done on this device, never uploaded.
Pitch and speed changer
Change the key of a song, or play it faster or slower, keeping the other the same. Done on this device.
BPM and key finder
Drop an audio file and read its tempo, key and Camelot code. The song is analysed on this device.
Other conversions
Guides
- How to turn audio into a videoTo put a song, a podcast episode or a voice note on YouTube, you need a video. Here is how to make one from the sound and a single picture.