M4A is an extension used to represent a compressed audio file in an MPEG-4 container. The standard file name extension defined by MPEG-4 is MP4 that covers both audio and video but MPEG-4 files that contain only audio typically carry an M4A extension. Actually, this file format was not very popular until Apple Inc. first used it on iTunes and iPod for songs using either Advanced Audio Coding (AAC) or Apple Lossless (ALAC) codecs to differentiate it from other audio files. MPEG-4 since 2007.
M4A
Extension: M4A (MPEG-4 audio)
Category: Audio File
Popularity: Among Apple users
Developer: Apple Inc.
Facts about M4A
M4A audio files are not protected. Protected files usually have an M4P extension.
The audio in M4A can be decoded back to the original quality it had before compression.
Most songs on M4A in the iTunes Store are paid but there are also special offers and gifts from time to time.
The iTunes Store also supplies music in formats other than M4A.
A song in M4A can be set directly as a ringtone on an iPhone simply by changing the file extension from M4A to M4R with iTunes.
It is a codec designed to provide coding without loss of quality that takes up little space.
Pros: The file in M4A format is compressed, but without loss of quality. Also in favor that M4A has no DRM (Digital Rights Management) protection and therefore can be edited and transferred with greater freedom.
Cons: M4A has no recognition problems on iTunes, iPod and other Apple devices, but its poor compatibility with other devices makes playback of M4A files not as comfortable as MP3 files.
M4A vs MP3
In general M4A is considered the successor of MP3 because it does the same as this but compared to MP3, the M4A can compress audio at the same bit rate in a smaller file. M4A files usually have a stereo bit rate of 128kbps, 192kbps or 256kbps. (By the way, bit rate refers to the amount of information that is transmitted within a given amount of time through a digital network. The common way to measure the bit rate is in kbits / s and Mbps, that is kilobytes and megabytes per second. In general, it doesn’t matter which unit you use, the higher the number, the higher the speed or the better quality). If you are familiar with music coding, it is advisable to save the music in M4A at 192kbps so that we can obtain high quality and a manageable file. For more information, see the comparison below.
Quality: For obvious reasons an M4A file with ALAC compression has the best quality since nothing of the original audio signal will be lost. And even for a file encoded with AAC compression with losses, tests indicate that it still gives better sound quality than MP3 files encoded at the same bit rates, especially when the bit rate is equal to or less than 128kbps.
File size: The size of the file and its quality are directly related to the bit rate. When it goes up, it will also increase the sound quality as well as the file size. For example, to obtain the same quality, an MP3 song needs to be encoded around 192kbps, while one in M4A is enough with 128kbps, which translates into a smaller file size.
Compatibility: Without a doubt, MP3 is still the norm in the audio industry. Almost all software and hardware is compatible with it. Instead, M4A files can only be read on PC, iPod, iTunes and other Apple devices.
