Convert M4A to AAC
About M4A
M4A is a file extension for an audio file encoded with Advanced Audio Coding (AAC) or Apple Lossless Audio Codec (ALAC). It is a container format based on the MPEG-4 standard, similar to the .mp4 video format, but used exclusively for audio. Apple adopted M4A for the iTunes Store, so it's most commonly associated with the Apple ecosystem. It offers a good balance of quality and file size and provides excellent support for metadata.
About AAC
Advanced Audio Coding (AAC) was designed to be the successor to the MP3 format. It generally delivers higher-quality audio than MP3 at the same bitrate, especially at lower bitrates. AAC is the standard audio format for YouTube, Apple's iTunes, and is widely used on mobile devices and digital video broadcasting. It's a very efficient codec, but it is a patented technology, which has implications for its use in some open-source projects.
M4A vs AAC
| Feature | M4A | AAC |
|---|---|---|
| Compression | lossy (AAC) or lossless (ALAC) | lossy |
| Max Bitrate | 320 kbps (AAC), 9216 kbps (ALAC) | 576 kbps |
| Typical File Size (per minute) | 3-4 MB per minute (AAC), 20-30 MB per minute (ALAC) | 3-4 MB per minute |
| Quality Rating | 4 | 4 |
| Patent Status | patented | patented |
| Year Introduced | 2001 | 1997 |
| Developed By | Apple | ISO/IEC Moving Picture Experts Group |
Frequently Asked Questions
What is the difference between M4A and MP4?
M4A is essentially an audio-only version of the MP4 container. While an MP4 file can contain video, audio, and subtitles, an M4A file is restricted to audio. This distinction helps media players differentiate between audio-only and video files.
Can I rename .m4a to .mp4?
Technically, you can, and some players might still play the audio. However, it's not recommended as it can cause confusion for both users and software. The .m4a extension specifically signals that the file contains only audio.
Is AAC the same as M4A?
Not exactly. AAC is the audio encoding standard (the codec). M4A is a file extension for an audio file that is encoded with AAC. So, an .m4a file is a container, and the audio inside is typically AAC-encoded. Think of AAC as the engine and M4A as the car.
Which is better, AAC or MP3?
Most listening tests conclude that AAC produces better audio quality than MP3 at the same bitrate. This advantage is more pronounced at lower bitrates (e.g., 128kbps and below). For this reason, many streaming services have adopted AAC.
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