M4B, Audiobook/podcast extension with AAC or ALAC encoded audio in an MPEG-4 container. Audio within the m4a file is typically encoded with AAC, although lossless ALAC may also be used. M4A, an audio-only MPEG-4 file, used by Apple for unprotected music downloaded from their Then play the MP3 files on your favorite audio players or another third-party music apps. But with the help of Audible Converter, you can Convert Audible Audiobook AAX to MP3. Generally, AAX files are encoded by DRM and you can only listen to Audible audiobooks on assigned software. M4B contains AAC or ALAC encoded audio in an MPEG-4 container.ĪAX file format is created by Audible. AAX(.aax)Īudiobook format, which is a variable-bitrate (allowing high quality) M4B file encrypted with DRM. The result in real terms is layer 3 shrinks the original sound data from a CD (with a bit rate of 1411.2 kilobits per one second of stereo music) by a factor of 12 (down to 112-128kbps) without sacrificing sound quality. It also adds a MDCT (Modified Discrete Cosine Transform) that implements a filter bank, increasing the frequency resolution 18 times higher than that of layer 2. The stuff the human ear doesn't hear anyway). Layer 3 uses perceptual audio coding and psycho acoustic compression to remove all superfluous information (more specifically, the redundant and irrelevant parts of a sound signal.

Layer 3 is one of three coding schemes (layer 1, layer 2 and layer 3) for the compression of audio signals. MP3 is the name of the file extension and also the name of the type of file for MPEG, audio layer 3. The good news is that, in most cases, you won't be able to hear the difference. In the context of audio, that means sacrificing quality and fidelity for file size. Lossy compression is a form of compression that loses data during the compression process.

Apple file format