Audio File Convert exports to 20 audio file formats and a multitude of codecs, all of which are shown with the -hf
option.
Uncompressed Audio
File formats: AIFC
AIFF
NeXT
Sd2f
WAVE
RF64
The original formats for storing audio files were all uncompressed because these are easy to work with, and can be played by even very early CPUs. However, uncompressed audio files are very large, easily going up to 10 MB/minute. These formats all share similar codec options like I8
BEI16
BEI24
BEI32
BEF32
BEF64
. Smaller numbers give smaller files, but larger numbers give higher quality. If you're not sure what to choose, go with BEI32
or LEI32
.
Compressed Audio
File formats: 3gpp
3gp2
adts
ac-3
amrf
m4af
m4bf
caff
ec-3
flac
mp4f
Not every codec is supported by every file format, but you can use this as a guide to get started choosing your codec. Once you've chosen a codec, you can look at the output of afconvert -hf
to pick a suitable container file format.
(Note: I have excluded the MPG formats such as MPG3/MP3 from this list because they just do not work.)
Syntax
Once you've chosen a file format and codec, you run afconvert like this:
afconvert -f FORMAT -d CODEC SOURCEFILE [-o DESTINATIONFILE]
It is necessary to specify both the file format and the codec, otherwise an error is shown. If you omit the -o
option, afconvert will pick a name and extension based on the other inputs.
Examples
If you have an audio file called MyAudio.m4a
you could try these commands.
# AIFF
afconvert -f AIFF -d BEI32 MyAudio.m4a -o MyAudio.aiff
# WAVE
afconvert -f WAVE -d LEI32 MyAudio.m4a -o MyAudio.wav
# Apple Lossless
afconvert -f m4af -d alac MyAudio.m4a -o MyAudio.m4a
# FLAC
afconvert -f flac -d flac MyAudio.m4a -o MyAudio.flac
# AAC
afconvert -f mp4f -d aac MyAudio.m4a -o MyAudio.mp4
afconvert --help
. Many (not all, but afconvert is one of them) command line programs will print some documentation in response to the--help
option. – Harald Hanche-Olsen Jul 30 '19 at 15:45