Does this tool upload my audio file?

No. This tool only generates a command you run locally. Your audio files never leave your computer.

Is audio quality lost during conversion?

No. The default command re-muxes (copies) the audio stream without re-encoding, so there is zero quality loss. The bitrate and fidelity remain identical.

What is the difference between AAC and M4A?

AAC is a codec (audio encoding algorithm). M4A is a file container (MPEG-4 Audio) that holds AAC-encoded audio. An .m4a file almost always contains AAC audio — the main difference is the container wrapper, not the audio data itself.

Do I need to install anything?

You need FFmpeg installed on your system. It is free and available for Windows, macOS, and Linux at ffmpeg.org. Many systems (especially Linux/macOS with Homebrew) already have it.

Can I batch-convert multiple files?

Yes. On Linux/macOS run: for f in *.aac; do ffmpeg -i "$f" -c:a copy "${f%.aac}.m4a"; done — this converts every .aac file in the current directory.

Will this work on Windows?

Yes. Install FFmpeg for Windows (ffmpeg.org), add it to your PATH, then run the generated command in PowerShell or Command Prompt.

AAC to M4A Converter

Name: AAC to M4A Converter
Availability: InStock
Author: Nham Vu

Get a personalized FFmpeg command to convert any AAC file to M4A — no upload required, runs on your own machine.

FFmpeg Command Builder

Enter your filenames and copy the ready-to-run terminal command.

Input filename *

Output filename (optional — leave blank to auto-generate)

Mode

Lossless re-mux (recommended) Re-encode AAC

Copies the audio stream as-is — zero quality loss, very fast.

Generated command

ffmpeg -i <input.aac> -c:a copy <output.m4a>

Batch Convert All AAC Files in a Folder

Run this one-liner in your terminal (Linux/macOS):

for f in *.aac; do ffmpeg -i "$f" -c:a copy "${f%.aac}.m4a"; done

On Windows (PowerShell):

Get-ChildItem *.aac | ForEach-Object { ffmpeg -i $_.Name -c:a copy ($_.BaseName + ".m4a") }

AAC vs M4A — What Is the Difference?

Same codec, different container.

Property	.aac	.m4a
Container	Raw ADTS stream	MPEG-4 (ISO Base Media)
Audio codec	AAC	AAC (same codec)
Quality loss on convert	—	None (re-mux only)
Apple compatibility	Partial	Full (iTunes, Music.app)
Metadata support	Limited	Rich (title, artist, cover art)
Chapter support	No	Yes
Typical use	Streaming, downloads	Apple ecosystem, podcasts

How to Install FFmpeg

Windows

Download the build from ffmpeg.org/download.html, extract it, and add the bin/ folder to your system PATH.

macOS (Homebrew)

brew install ffmpeg

Linux (Ubuntu/Debian)

sudo apt install ffmpeg

Tips

Use -c:a copy to avoid re-encoding — conversion is instant and lossless.
Add -map_metadata 0 after the input flag to preserve all existing metadata tags.
File paths with spaces must be wrapped in quotes, e.g. "my file.aac".
Verify FFmpeg is installed by running ffmpeg -version in your terminal.

Copied!

Summary

Get a personalized FFmpeg command to convert any AAC file to M4A — no upload required, runs on your own machine.

How it works

Enter the name of your source AAC file in the command builder.
Optionally set the desired output filename (defaults to the same name with .m4a extension).
Copy the generated FFmpeg command.
Open a terminal on your computer and paste the command.
Run the command — FFmpeg re-muxes the file in seconds without re-encoding.

Use cases

Re-container AAC audio for Apple devices that expect .m4a.
Fix playback issues in iTunes, Music.app, or QuickTime caused by the .aac extension.
Prepare audio tracks for video editing software that requires M4A containers.
Batch-convert a folder of AAC files to M4A with a one-line shell loop.
Archive podcast episodes in the standard M4A format.
Convert AAC streams downloaded from the web for use in GarageBand or Logic Pro.

Frequently Asked Questions

Last updated: 2026-06-09 · Reviewed by Nham Vu