M4A is the file extension used for MPEG-4 family audio files. It usually holds AAC audio and is common on Apple devices and in video editing. M4A is mainly the container, while AAC is the codec that compresses and decodes the audio.
M4A names the container
An audio file can store not only the audio itself but also the track title, artist name, album artwork, and more. M4A is the file format that packages that information together with the audio data. The extension is normally .m4a, and AAC is the usual codec inside, but you cannot always determine the internal codec from the extension alone.
Difference from AAC
AAC is a way of compressing audio. Because M4A files most often contain AAC, the two are sometimes talked about as if they meant the same thing. In the export dialog, though, the container, codec, bitrate, sample rate, and channel count are separate settings you need to check.
What it suits
It is a good option for listening to space-saving audio on a device, handing material to a video editor, or sharing a file for approval. The best format changes with the recipient’s setup. Keep a WAV at the requested settings as your production and delivery master, and treat M4A as a file you create for a specific use.
Differences from MP3, WAV, and FLAC
MP3 is a file holding the MP3 codec, WAV is a format that in production usually holds PCM, and FLAC is a lossless audio format. What sets M4A apart is that it is usually paired with AAC. Rather than standardizing on one of them, use each according to editing, storage, sharing, and what the destination requires.
Check before exporting
Keep the pre-conversion WAV, confirm the format and bitrate the destination requires, and then make the M4A. Converting MP3 or AAC repeatedly into other lossy formats will not bring the original information back. To create an M4A (AAC) from a WAV, use the WAV to M4A converter.
