mp3fs

mp3fs is a read-only FUSE filesystem which transcodes between audio formats (currently FLAC to MP3) on the fly when files are opened and read.

It can let you use a FLAC collection with software and/or hardware which only understands the MP3 format, or transcode files through simple drag-and-drop in a file browser.

Usage

Mount your music like so (for example)

$ mp3fs -b 192 /mnt/music /mnt/mp3 -o allow_other,ro

or use the following entry in /etc/fstab:

mp3fs#/mnt/music /mnt/mp3 fuse allow_other,ro,bitrate=192 0 0

Here are the original files:

$ ls -l /mnt/music/Machinarium
total 271252
-rw-r--r-- 1 khenriks khenriks 30661302 Feb 14  2012 1-01 The Bottom.flac
-rw-r--r-- 1 khenriks khenriks 22246923 Feb 14  2012 1-02 The Sea.flac
-rw-r--r-- 1 khenriks khenriks 20505800 Feb 14  2012 1-03 Clockwise Operetta.flac
-rw-r--r-- 1 khenriks khenriks 19319831 Feb 14  2012 1-04 Nanorobot Tune.flac
...

which now show up as mp3s on the mountpoint:

$ ls -l /mnt/mp3/Machinarium
total 81030
-rw-r--r-- 1 khenriks khenriks  8607397 Feb 14  2012 1-01 The Bottom.mp3
-rw-r--r-- 1 khenriks khenriks  6295871 Feb 14  2012 1-02 The Sea.mp3
-rw-r--r-- 1 khenriks khenriks  6287732 Feb 14  2012 1-03 Clockwise Operetta.mp3
-rw-r--r-- 1 khenriks khenriks  5157984 Feb 14  2012 1-04 Nanorobot Tune.mp3
...

You can treat them just like regular files.

$ mutagen-inspect /mnt/mp3/Machinarium/1-01\ The\ Bottom.mp3
-- /mnt/mp3/Machinarium/1-01 The Bottom.mp3
- MPEG 1 layer 3, 192000 bps, 44100 Hz, 330.32 seconds (audio/mp3)
APIC= (image/png, 679371 bytes)
TALB=Machinarium
TCON=Soundtrack
TDRC=2009-10-16
TIT2=The Bottom
TLEN=330279
TPE1=Tomáš Dvořák
TPE2=Tomáš Dvořák
TPOS=1/1
TRCK=1/14
TSSE=MP3FS

$ time cp /mnt/mp3/Machinarium/1-01\ The\ Bottom.mp3 /tmp

real    0m7.788s
user    0m0.000s
sys     0m0.012s

As far as your programs are concerned, they are just regular files.

More Information

If you’re interested to know more, check out the README or source on the GitHub page. You can also browse the manpage on this site.