ffmpeg -i Ke\$ha\ -\ Sleazy.mp3 -acodec libaacplus -ab 64K -ar 44100 -vn -map_metadata g out4.m4a
ffmpeg version N-40926-g6374ee7 Copyright (c) 2000-2012 the FFmpeg developers
  built on Jun 26 2012 13:10:49 with llvm_gcc 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2336.9.00)
  configuration: --enable-static --enable-shared --enable-gpl --enable-nonfree --enable-libmp3lame --enable-libaacplus
  libavutil      51. 53.100 / 51. 53.100
  libavcodec     54. 21.101 / 54. 21.101
  libavformat    54.  5.101 / 54.  5.101
  libavdevice    53.  4.100 / 53.  4.100
  libavfilter     2. 75.100 /  2. 75.100
  libswscale      2.  1.100 /  2.  1.100
  libswresample   0. 15.100 /  0. 15.100
  libpostproc    52.  0.100 / 52.  0.100
[mp3 @ 0x7ffc1c01ae00] max_analyze_duration 5000000 reached at 5015510
[mp3 @ 0x7ffc1c01ae00] Estimating duration from bitrate, this may be inaccurate
Input #0, mp3, from 'Ke$ha - Sleazy.mp3':
  Metadata:
    title           : Sleazy
    publisher       : RCA
    genre           : Other
    album           : Cannibal [EP]
    track           : 3
    artist          : Ke$ha
    album_artist    : Ke$ha
    composer        : Benjamin Levin/Kesha Sebert/Klas Åhlund/Lukasz "Dr. Luke" Gottwald/Shondrae Crawford
    date            : 2010
  Duration: 00:03:26.08, start: 0.000000, bitrate: 127 kb/s
    Stream #0:0: Audio: mp3, 44100 Hz, stereo, s16, 128 kb/s
Output #0, ipod, to 'out4.m4a':
  Metadata:
    title           : Sleazy
    publisher       : RCA
    genre           : Other
    album           : Cannibal [EP]
    track           : 3
    artist          : Ke$ha
    album_artist    : Ke$ha
    composer        : Benjamin Levin/Kesha Sebert/Klas Åhlund/Lukasz "Dr. Luke" Gottwald/Shondrae Crawford
    date            : 2010
    encoder         : Lavf54.5.101
    Stream #0:0: Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo, s16, 64 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (mp3 -> libaacplus)
Press [q] to stop, [?] for help
Multiple frames in a packet from stream 0
size=    1626kB time=00:03:25.79 bitrate=  64.7kbits/s
video:0kB audio:1608kB global headers:0kB muxing overhead 1.142369%