Extract M4A Audio from MOV

About MOV and M4A

MOV is Apple's QuickTime container, the default for iPhone recordings and screen captures on macOS. The audio track inside is usually AAC, which converts cleanly to anything here.

M4A is AAC audio in an MP4 container — the default format of the Apple ecosystem and most streaming services. AAC compresses more efficiently than MP3, so the same bitrate sounds a little better.

Extracting audio from MOV re-encodes only the audio track — the video is discarded, so even long files finish quickly.

How the conversion works

This tool runs FFmpeg — the same engine behind most media software — compiled to WebAssembly, entirely in the browser. The file is read locally, converted locally and saved straight from memory; nothing is ever uploaded, which also means no queues and no server-side file size limits.

The converter itself is a one-time ~31 MB download on the first conversion, cached by the browser afterwards. Once it is loaded, everything works offline.