Media: Audio and Audiobook

Opened on March 10, 2025. Last updated by The POOG, March 11, 2025.

Formats and File Types

Lossy Compressed Audio Formats

  • AAC. A codec with superior form of compression to MP3. The sound quality is a lot better.
  • AAX. An Audible audiobook format that uses an MPEG-4 container with encrypt and DRM. Audible does the transfer for you.
  • ADTS. Uses AAC codec. Uncommonly usedd.
  • M4A/M4B. Used by Apple like AAX is used by Audible. M4A is more for music and M4B for audiobooks.
  • M4P. M4P is a version of AAC with DRM.
  • MP3. A codec with perhaps the most loss although it may not be noticeable.
  • MP4. MP4 is a container that uses the AAC codec.
  • OGG. Holds Vorbis files, an open source type with superior audio quality and compression.
  • WMA. WMA or Windows Media Audio have both Lossy and Lossless formats.

Lossless Compressed Audio Formats

  • ALAC. An Apple codec that is now open source and royalty free. FLAC has superior compression.
  • FLAC. It is an open source codec with compression almost as good as MP3 without loss of any quality.
  • WAV. An older format, but has a lot larger file size.
  • WMA. WMA has a lossless format that use the same extension, is proprietary, and has the worst compression efficiency.

Choice

Although FLAC seems good, using the UkeySoft converter, FLAC files come out 3.7 times larger than the AAX file they are converted from. MPEG-4 from the same converter on the “lossless” setting come out fractionally smaller. Conversion to MPEG-4 is fast since the converter is only remoning the DRM.There is no point in conversion to FLAC since any loss in the AAX is simply carried forward and cannot be improved upon.

References

Sources of Audiobooks

File Conversion

Conversion Process

Downloadable (Subscription) Converters

Online Conversion

Media Players

  • VLC media player. Open source. Free. Plays most codecs with no codec packs needed – MPEG-2, MPEG-4, H.264, MKV, WebM, WMV, MP3.
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