[x]$ ffmpeg -formats | grep mp3
fmpeg version N-42915-g307a20c Copyright (c) 2000-2012 the FFmpeg developers
  built on Jul 26 2012 12:36:41 with gcc 4.4.6 (GCC) 20120305 (Red Hat 4.4.6-4)
  configuration: --enable-gpl --enable-libmp3lame --enable-libvo-aacenc --enable-libvorbis --enable-version3
  libavutil      51. 65.100 / 51. 65.100
  libavcodec     54. 44.101 / 54. 44.101
  libavformat    54. 20.100 / 54. 20.100
  libavdevice    54.  2.100 / 54.  2.100
  libavfilter     3.  3.100 /  3.  3.100
  libswscale      2.  1.100 /  2.  1.100
  libswresample   0. 15.100 /  0. 15.100
  libpostproc    52.  0.100 / 52.  0.100
 DE mp3             MPEG audio layer 3


$ ffmpeg -i 5e7be3cb31fc156715d5c0f048b00d20c6b87e7a -ar 44100 -ab 128k -t 90 5e7be3cb31fc156715d5c0f048b00d20c6b87e7a_a.mp3

ffmpeg version N-42915-g307a20c Copyright (c) 2000-2012 the FFmpeg developers
  built on Jul 26 2012 12:36:41 with gcc 4.4.6 (GCC) 20120305 (Red Hat 4.4.6-4)
  configuration: --enable-gpl --enable-libmp3lame --enable-libvo-aacenc --enable
-libvorbis --enable-version3
  libavutil      51. 65.100 / 51. 65.100
  libavcodec     54. 44.101 / 54. 44.101
  libavformat    54. 20.100 / 54. 20.100
  libavdevice    54.  2.100 / 54.  2.100
  libavfilter     3.  3.100 /  3.  3.100
  libswscale      2.  1.100 /  2.  1.100
  libswresample   0. 15.100 /  0. 15.100
  libpostproc    52.  0.100 / 52.  0.100
[flac @ 0x30cf240] max_analyze_duration 5000000 reached at 5015510
Input #0, flac, from '5e7be3cb31fc156715d5c0f048b00d20c6b87e7a':
  Metadata:
    LC              : BIS-SACD-1536
    TITLE           : (Sweeter than roses, Z.585 No.1) - Sweeter than roses, Z.5
85 No.1
    ALBUM           : Victorious Love - Carolyn Sampson sings Purcell
    GENRE           : (32)Baroque
    DISC            : 1/1
    ITUNESCOMPILATION: 0
    ARTIST          : Lasla, Anne-Marie
    COMPOSER        : Purcell, Henry
    PERFORMER       : Lasla, Anne-Marie
    MUSICIAN_CREDITS_LIST: Bass Viol?Lasla, Anne-Marie?
    TAGGING_TIME    : 2010-12-16T12:41:28+01:00
    COPYRIGHT       : eClassical
    PUBLISHER       : eClassical
    COMMENT         : Downloaded from eClassical.com. From album BIS-SACD-1536
    YEAR            : 2007-08-30
    track           : 1/19
  Duration: 00:03:25.86, bitrate: 1241 kb/s
    Stream #0:0: Audio: flac, 44100 Hz, stereo, s32
    Stream #0:1: Video: mjpeg, yuvj420p, 1144x1144 [SAR 300:300 DAR 1:1], 90k tb
r, 90k tbn, 90k tbc
    Metadata:
      comment         : Cover (front)
      title           : Cover image for BIS-SACD-1536
    Stream #0:2: Video: mjpeg, yuvj420p, 1144x1144 [SAR 300:300 DAR 1:1], 90k tb
r, 90k tbn, 90k tbc
    Metadata:
      comment         : Cover (front)
      title           : Cover image for BIS-SACD-1536
    Stream #0:3: Video: mjpeg, yuvj420p, 1144x1144 [SAR 300:300 DAR 1:1], 90k tb
r, 90k tbn, 90k tbc
    Metadata:
      comment         : Cover (front)
      title           : Cover image for BIS-SACD-1536
    Stream #0:4: Video: mjpeg, yuvj420p, 1144x1144 [SAR 300:300 DAR 1:1], 90k tb
r, 90k tbn, 90k tbc
    Metadata:
      comment         : Cover (front)
      title           : Cover image for BIS-SACD-1536
File '5e7be3cb31fc156715d5c0f048b00d20c6b87e7a_a.mp3' already exists. Overwrite
? [y/N] y
Output #0, mp3, to '5e7be3cb31fc156715d5c0f048b00d20c6b87e7a_a.mp3':
  Metadata:
    LC              : BIS-SACD-1536
    TITLE           : (Sweeter than roses, Z.585 No.1) - Sweeter than roses, Z.5
85 No.1
    ALBUM           : Victorious Love - Carolyn Sampson sings Purcell
    GENRE           : (32)Baroque
    DISC            : 1/1
    ITUNESCOMPILATION: 0
    ARTIST          : Lasla, Anne-Marie
    COMPOSER        : Purcell, Henry
    PERFORMER       : Lasla, Anne-Marie
    MUSICIAN_CREDITS_LIST: Bass Viol?Lasla, Anne-Marie?
    TAGGING_TIME    : 2010-12-16T12:41:28+01:00
    COPYRIGHT       : eClassical
    PUBLISHER       : eClassical
    COMMENT         : Downloaded from eClassical.com. From album BIS-SACD-1536
    YEAR            : 2007-08-30
    track           : 1/19
    Stream #0:0: Video: none, q=2-31, 128 kb/s, 90k tbn
    Metadata:
      comment         : Cover (front)
      title           : Cover image for BIS-SACD-1536
    Stream #0:1: Audio: none, 44100 Hz, 0 channels
Stream mapping:
  Stream #0:1 -> #0:0 (mjpeg -> ?)
  Stream #0:0 -> #0:1 (flac -> libmp3lame)
Encoder (codec none) not found for output stream #0:0