M4A usually contains AAC
M4A is commonly an MP4-family container holding AAC audio, although files can vary. The inspector reads the actual track codec.
Compatibility is the main reason to convert
MP3 may be required by older software or upload forms. If the destination accepts M4A, avoiding a lossy transcode can preserve more quality.
Do not overstate bitrate
Encoding a low-bitrate source at a larger MP3 bitrate does not restore information.
Keep the original
The M4A remains the better master when it is the original source.
Official marketplace references
Requirements can change. Review the source before publishing an important listing.
Mediabunny browser media toolkit documentation ↗