fjodor@fjodor-notizbuch:~$ ffmpeg -i Skream_and_Benga_-_Baauer_is_on_the_phone_b01qtc97_default.m4a -b:a 49k Skream_and_Benga_-_Baauer_is_on_the_phone_b01qtc97_default.mp3
WARNING: gnome-keyring:: couldn't connect to: /run/user/fjodor/keyring-WRCynR/pkcs11: No such file or directory
ffmpeg version 0.8.5-6:0.8.5-0ubuntu0.12.10.1, Copyright (c) 2000-2012 the Libav developers
  built on Jan 24 2013 14:49:20 with gcc 4.7.2
*** THIS PROGRAM IS DEPRECATED ***
This program is only provided for compatibility and will be removed in a future release. Please use avconv instead.
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'Skream_and_Benga_-_Baauer_is_on_the_phone_b01qtc97_default.m4a':
  Metadata:
    major_brand     : M4A
    minor_version   : 512
    compatible_brands: isomiso2
    encoder         : Lavf53.21.1
  Duration: 02:00:00.18, start: 0.000000, bitrate: 49 kb/s
    Stream #0.0(und): Audio: aac, 44100 Hz, 2 channels (FC), s16, 47 kb/s
File 'Skream_and_Benga_-_Baauer_is_on_the_phone_b01qtc97_default.mp3' already exists. Overwrite ? [y/N] y
Output #0, mp3, to 'Skream_and_Benga_-_Baauer_is_on_the_phone_b01qtc97_default.mp3':
  Metadata:
    major_brand     : M4A
    minor_version   : 512
    compatible_brands: isomiso2
    TSSE            : Lavf53.21.1
    Stream #0.0(und): Audio: libmp3lame, 44100 Hz, 2 channels, s16, 200 kb/s
Stream mapping:
  Stream #0.0 -> #0.0
Press ctrl-c to stop encoding
size=  168755kB time=7200.21 bitrate= 192.0kbits/s        ts/s
video:0kB audio:168755kB global headers:0kB muxing overhead 0.000134%