Introduction

MP3FS is A read-only FUSE filesystem which transcodes audio formats (currently FLAC) to MP3 on the fly when opened and read. This was written to enable me to use my FLAC collection with software and/or hardware which only understands MP3. e.g. gmediaserver to a netgear MP101 mp3 player.

It is also a novel alternative to traditional mp3 encoder applications. Just use your favorite file browser to select the files you want encoded and copy them somewhere!

How it Works

When a file is opened, the decoder and encoder are initialised and the file metadata is read. At this time the final filesize can be determined as we only support constant bitrate (CBR) mp3.

As the file is read, it is transcoded into an internal per-file buffer. This buffer continues to grow while the file is being read until the whole file is transcoded in memory. The memory is freed only when the file is closed. This simplifies the implementation.

Seeking within a file will cause the file to be transcoded up to the seek point (if not already done). This is not usually a problem since most programs will read a file from start to finish. Future enhancements may provide true random seeking.

ID3 version 2.4 and 1.1 tags are created from the vorbis comments in the flac file. They are located at the start and end of the file respectively.

A special optimisation is made so that applicatins which scan for id3v1 tags do not have to wait for the whole file to be transcoded before reading the tag. This dramatically speeds up such applications.

For build instructions see INSTALL

Usage

NOTE:

The command line format changed from version 0.07 to 0.10, note
the comma.

mount your filesystem like this: (you will probably have to be root)

mp3fs musicdir,bitrate mountpoint [-o fuse_options]

e.g.:

mp3fs /mnt/music,128 /mnt/mp3 -o allow_other,ro

Recent versions of FUSE and mp3fs can be mounted from /etc/fstab using the following syntax (you must have /sbin/mount.fuse from the fuse-utils package)

mp3fs#/mnt/music,128 /mnt/mp3 fuse ro,allow_other 0  0

Here are the original files:

dave@bender:~/mp3fs$ ls -l /mnt/music/Smashing\ Pumpkins/Pisces\ Iscariot/
total 345732
-rw-r--r-- 1 mythtv mythtv 10267876 2005-06-19 18:36 01 - Soothe.flac
-rw-r--r-- 1 mythtv mythtv 23512276 2005-06-19 18:36 02 - Frail And Bedazzled.flac
-rw-r--r-- 1 mythtv mythtv 23332187 2005-06-19 18:36 03 - Plum.flac
-rw-r--r-- 1 mythtv mythtv 26402936 2005-06-19 18:36 04 - Whir.flac
-rw-r--r-- 1 mythtv mythtv 21591252 2005-06-19 18:36 05 - Blew Away.flac
-rw-r--r-- 1 mythtv mythtv 16719855 2005-06-19 18:36 06 - Pissant.flac
-rw-r--r-- 1 mythtv mythtv 33454889 2005-06-19 18:36 07 - Hello Kitty Kat.flac
-rw-r--r-- 1 mythtv mythtv 32073747 2005-06-19 18:36 08 - Obscured.flac
-rw-r--r-- 1 mythtv mythtv 17614217 2005-06-19 18:36 09 - Landslide.flac
-rw-r--r-- 1 mythtv mythtv 65406696 2005-06-19 18:36 10 - Starla.flac
-rw-r--r-- 1 mythtv mythtv 18651734 2005-06-19 18:36 11 - Blue.flac
-rw-r--r-- 1 mythtv mythtv 25055200 2005-06-19 18:36 12 - Girl Named Sandoz.flac
-rw-r--r-- 1 mythtv mythtv 28060023 2005-06-19 18:36 13 - La Dolly Vita.flac
-rw-r--r-- 1 mythtv mythtv 11432008 2005-06-19 18:36 14 - Spaced.flac

And now you can use the (virtual) mp3 files from the MP3FS mountpoint:

dave@bender:~/mp3fs$ ls -l /mnt/mp3/Smashing\ Pumpkins/Pisces\ Iscariot/
total 345732
-rw-r--r-- 1 mythtv mythtv  2446849 2005-06-19 18:36 01 - Soothe.mp3
-rw-r--r-- 1 mythtv mythtv  3197934 2005-06-19 18:36 02 - Frail And Bedazzled.mp3
-rw-r--r-- 1 mythtv mythtv  3467503 2005-06-19 18:36 03 - Plum.mp3
-rw-r--r-- 1 mythtv mythtv  4003745 2005-06-19 18:36 04 - Whir.mp3
-rw-r--r-- 1 mythtv mythtv  3414845 2005-06-19 18:36 05 - Blew Away.mp3
-rw-r--r-- 1 mythtv mythtv  2413413 2005-06-19 18:36 06 - Pissant.mp3
-rw-r--r-- 1 mythtv mythtv  4348572 2005-06-19 18:36 07 - Hello Kitty Kat.mp3
-rw-r--r-- 1 mythtv mythtv  5132656 2005-06-19 18:36 08 - Obscured.mp3
-rw-r--r-- 1 mythtv mythtv  3099704 2005-06-19 18:36 09 - Landslide.mp3
-rw-r--r-- 1 mythtv mythtv 10542719 2005-06-19 18:36 10 - Starla.mp3
-rw-r--r-- 1 mythtv mythtv  3210041 2005-06-19 18:36 11 - Blue.mp3
-rw-r--r-- 1 mythtv mythtv  3449127 2005-06-19 18:36 12 - Girl Named Sandoz.mp3
-rw-r--r-- 1 mythtv mythtv  4098213 2005-06-19 18:36 13 - La Dolly Vita.mp3
-rw-r--r-- 1 mythtv mythtv  2337344 2005-06-19 18:36 14 - Spaced.mp3

dave@bender:~/mp3fs$ id3info /mnt/mp3/Smashing\ Pumpkins/Pisces\ Iscariot/01\ -\ Soothe.mp3

*** Tag information for /mnt/mp3/Smashing Pumpkins/Pisces Iscariot/01 - Soothe.mp3
=== TSSE (Software/Hardware and settings used for encoding): LAME v3.96.1
=== TIT2 (Title/songname/content description): Soothe
=== TPE1 (Lead performer(s)/Soloist(s)): Smashing Pumpkins
=== TALB (Album/Movie/Show title): Pisces Iscariot
=== TRCK (Track number/Position in set): 1
*** mp3 info
MPEG1/layer III
Bitrate: 128KBps
Frequency: 44KHz

dave@bender:~/mp3fs$ time cp /mnt/mp3/Smashing\ Pumpkins/Pisces\ Iscariot/01\ -\ Soothe.mp3 /tmp/

real    0m12.917s
user    0m0.004s
sys     0m0.020s

dave@bender:~/mp3fs$ xmms /mnt/mp3/Smashing\ Pumpkins/Pisces\ Iscariot/* &

Download

Releases are made through the sourceforge files page:

http://sourceforge.net/project/showfiles.php?group_id=174365

Development

MP3FS uses darcs for revision control. You can obtain the full repository here:

darcs get http://mp3fs.sourceforge.net/mp3fs

MP3FS is written in C and requires the following libraries:

• fuse (libfuse-dev)
• flac (libflac-dev)
• lame (liblame-dev)
• libid3tag (libid3tag0-dev)

Additionally, MP3FS includes GPL'd code from a number of other projects:

• Talloc, A heirachical memory allocator from samba4.
• A class implementation in C from pyflag (pyflag.sourceforge.net)

Licence

This program can be distributed under the terms of the GNU GPL. See the file COPYING.