id	summary	reporter	owner	description	type	status	priority	component	version	resolution	keywords	cc	blockedby	blocking	reproduced	analyzed
2075	Wrong bitrate when transcoding to aac	ddnlkd		"Summary of the bug:
I want to transcode from a mp3 file to aac file, the command line is as following :
ffmpeg -y -v 9 -loglevel 99 -i 10.mp3 -acodec libfaac -ac 2 -ab 32000 10.aac
I Specified the bitrate as 32kbps, but the output file bitrate is 58.5kbits/s.

Following is the output and attach is the oringal file:
ffmpeg version 1.0.1 Copyright (c) 2000-2012 the FFmpeg developers
  built on Dec 25 2012 11:55:44 with gcc 3.4.6 (GCC) 20060404 (Red Hat 3.4.6-10)
  configuration: --prefix=/usr --enable-gpl --enable-shared --enable-libfaac --enable-nonfree --disable-yasm
  libavutil      51. 73.101 / 51. 73.101
  libavcodec     54. 59.100 / 54. 59.100
  libavformat    54. 29.104 / 54. 29.104
  libavdevice    54.  2.101 / 54.  2.101
  libavfilter     3. 17.100 /  3. 17.100
  libswscale      2.  1.101 /  2.  1.101
  libswresample   0. 15.100 /  0. 15.100
  libpostproc    52.  0.100 / 52.  0.100
[mp3 @ 0x82f1500] Format mp3 probed with size=131072 and score=51
[mp3 @ 0x82f1500] pad 576 576
[mp3 @ 0x82f1500] File position before avformat_find_stream_info() is 107743
[mjpeg @ 0x82f9100] marker=d8 avail_size_in_buf=45910
[mjpeg @ 0x82f9100] marker parser used 0 bytes (0 bits)
[mjpeg @ 0x82f9100] marker=e0 avail_size_in_buf=45908
[mjpeg @ 0x82f9100] marker parser used 16 bytes (128 bits)
[mjpeg @ 0x82f9100] marker=fe avail_size_in_buf=45890
[mjpeg @ 0x82f9100] marker parser used 60 bytes (480 bits)
[mjpeg @ 0x82f9100] marker=db avail_size_in_buf=45828
[mjpeg @ 0x82f9100] index=0
[mjpeg @ 0x82f9100] qscale[0]: 0
[mjpeg @ 0x82f9100] marker parser used 67 bytes (536 bits)
[mjpeg @ 0x82f9100] marker=db avail_size_in_buf=45759
[mjpeg @ 0x82f9100] index=1
[mjpeg @ 0x82f9100] qscale[1]: 0
[mjpeg @ 0x82f9100] marker parser used 67 bytes (536 bits)
[mjpeg @ 0x82f9100] marker=c0 avail_size_in_buf=45690
[mjpeg @ 0x82f9100] sof0: picture: 240x240
[mjpeg @ 0x82f9100] component 0 2:2 id: 0 quant:0
[mjpeg @ 0x82f9100] component 1 1:1 id: 1 quant:1
[mjpeg @ 0x82f9100] component 2 1:1 id: 2 quant:1
[mjpeg @ 0x82f9100] pix fmt id 22111100
[mjpeg @ 0x82f9100] marker parser used 17 bytes (136 bits)
[mjpeg @ 0x82f9100] marker=c4 avail_size_in_buf=45671
[mjpeg @ 0x82f9100] class=0 index=0 nb_codes=12
[mjpeg @ 0x82f9100] marker parser used 31 bytes (248 bits)
[mjpeg @ 0x82f9100] marker=c4 avail_size_in_buf=45638
[mjpeg @ 0x82f9100] class=1 index=0 nb_codes=251
[mjpeg @ 0x82f9100] marker parser used 181 bytes (1448 bits)
[mjpeg @ 0x82f9100] marker=c4 avail_size_in_buf=45455
[mjpeg @ 0x82f9100] class=0 index=1 nb_codes=12
[mjpeg @ 0x82f9100] marker parser used 31 bytes (248 bits)
[mjpeg @ 0x82f9100] marker=c4 avail_size_in_buf=45422
[mjpeg @ 0x82f9100] class=1 index=1 nb_codes=251
[mjpeg @ 0x82f9100] marker parser used 181 bytes (1448 bits)
[mjpeg @ 0x82f9100] escaping removed 218 bytes
[mjpeg @ 0x82f9100] marker=da avail_size_in_buf=45239
[mjpeg @ 0x82f9100] component: 0
[mjpeg @ 0x82f9100] component: 1
[mjpeg @ 0x82f9100] component: 2
[mjpeg @ 0x82f9100] marker parser used 45020 bytes (360155 bits)
[mjpeg @ 0x82f9100] marker=d9 avail_size_in_buf=0
[mjpeg @ 0x82f9100] decode frame unused 0 bytes
[mp3 @ 0x82f1500] max_analyze_duration 5000000 reached at 5015510
[mp3 @ 0x82f1500] File position after avformat_find_stream_info() is 189663
Input #0, mp3, from '10.mp3':
  Metadata:
    artist          : 曲婉婷
    title           : 我的歌声里
    Tagging time    : 2012-09-03T03:39:33
    album           : 网络新神曲
    TYER            : 2012-07-20
  Duration: 00:03:36.71, start: 0.000000, bitrate: 131 kb/s
    Stream #0:0, 194, 1/14112000: Audio: mp3, 44100 Hz, stereo, s16, 128 kb/s
    Stream #0:1, 1, 1/90000: Video: mjpeg, yuvj420p, 240x240 [SAR 1:1 DAR 1:1], 1/90000, 90k tbr, 90k tbn, 90k tbc
    Metadata:
      title           : e
      comment         : Cover (front)
[abuffer @ 0x8369c20] Setting entry with key 'time_base' to value '1/44100'
[abuffer @ 0x8369c20] Setting entry with key 'sample_rate' to value '44100'
[abuffer @ 0x8369c20] Setting entry with key 'sample_fmt' to value 's16'
[abuffer @ 0x8369c20] Setting entry with key 'channel_layout' to value '0x3'
[graph 0 input from stream 0:0 @ 0x83589e0] tb:1/44100 samplefmt:s16 samplerate:44100 chlayout:0x3
[aformat @ 0x836fb60] Setting entry with key 'sample_fmts' to value 's16'
[aformat @ 0x836fb60] Setting entry with key 'channel_layouts' to value '0x3'
Output #0, adts, to '10.aac':
  Metadata:
    artist          : 曲婉婷
    title           : 我的歌声里
    Tagging time    : 2012-09-03T03:39:33
    album           : 网络新神曲
    TYER            : 2012-07-20
    encoder         : Lavf54.29.104
    Stream #0:0, 0, 1/90000: Audio: aac, 44100 Hz, stereo, s16, 32 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (mp3 -> libfaac)
Press [q] to stop, [?] for help
[mp3 @ 0x82f1500] demuxer injecting skip 1105
[mp3 @ 0x82f8380] skip 1105 samples due to side data
[mp3 @ 0x82f8380] skip 1105/1152 samples
EOF on sink link output stream 0:0:default.59.0kbits/s    
No more output streams to write to, finishing.
[libfaac @ 0x831b980] Trying to remove 81 more samples than are in the que
size=    1547kB time=00:03:36.71 bitrate=  58.5kbits/s    
video:0kB audio:1547kB subtitle:0 global headers:0kB muxing overhead 0.000000%
[AVIOContext @ 0x82f9ae0] Statistics: 3575132 bytes read, 0 seeks"	defect	closed	normal	undetermined	1.0.1	invalid	libfaac				0	0