Package: media-types
Version: 5.0.0
The current /etc/mime.types has
audio/mpeg mpga mpega mp1 mp2 mp3 m4a
audio/mp4
This association for the .m4a extension is incorrect. Please update this to
audio/mpeg mpga mpega mp1 mp2 mp3
audio/mp4 m4a
RFC 3003 specified the audio/mpeg type for “layer I, layer II and layer III in
the MPEG-1 and MPEG-2 standards”. For clarity, this includes .mp3, which is
MPEG-{1,2} audio layer III. But it does not include .m4a, which is for MPEG-4
Part 14 (MP4) audio files.
RFC 4337 specified audio/mp4 for “MP4 files with audio but without visual
presentation”. This is the correct type for .m4a.
(While the audio/mp4 type is standard, the .m4a extension was never officially
standardized; however, it’s now very common due to its use by iTunes. My
understanding is that this file is supposed to include common extensions. In
any case, the extensions it does include should be included correctly.)
https://www.rfc-editor.org/rfc/rfc3003.html
https://www.rfc-editor.org/rfc/rfc4337.html
https://en.wikipedia.org/wiki/MPEG-4_Part_14#Filename_extensions
Anders
