Output file longer than source

[Abu Abdullah]

Summary of the bug:
mp3 created from rm file is longer than the original.
How to reproduce:

% ffmpeg -i 001.rm -b:a 16k 001.mp3
ffmpeg version N-73648-g90dd6ad Copyright (c) 2000-2015 the FFmpeg developers
  built with gcc 4.9.2 (GCC)
  configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-av
isynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enab
le-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --
enable-libdcadec --enable-libfreetype --enable-libgme --enable-libgsm --enable-l
ibilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enab
le-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --en
able-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --ena
ble-libtwolame --enable-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc
 --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enabl
e-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-lzma --ena
ble-decklink --enable-zlib
  libavutil      54. 28.100 / 54. 28.100
  libavcodec     56. 48.100 / 56. 48.100
  libavformat    56. 40.100 / 56. 40.100
  libavdevice    56.  4.100 / 56.  4.100
  libavfilter     5. 21.100 /  5. 21.100
  libswscale      3.  1.101 /  3.  1.101
  libswresample   1.  2.100 /  1.  2.100
  libpostproc    53.  3.100 / 53.  3.100
Input #0, rm, from '001.rm':
  Metadata:
    title           : ╟ط╘╤و╪ ╟ط├µط
    author          : ╟ط╘و╬ ع═ع╧ غ╟╒╤ ╟ط╧وغ ╟ط├ط╚╟غو
    copyright       : www.islamway.com
    comment         : ╟ط╟═╧╟╦ ▌و ╟ط╧وغ µ╟ط╚╧┌╔ - µ╟ط╙غ╔ µ╟╩╚╟┌ ╙غ╔ ╟ط╤╙µط µف╧ه ╟
ط╙ط▌ ة ═▀ع ط╚╙ ╟ط╬ع╟╤ ▌و ╟طµ▐╩ ╟ط═╟طو ة µ═▀ع ╩█╪و╔ ╟طµ╠ف µ╟ط▀▌وغ ة ═▀ع ط╚╙ ╟ط┼و╘
╤╚ ة ط╚╙ ╟ط▀┌╚ ╟ط┌╟طو ة فط و╠µ╥ ╙╚ ╟ط▀╟▌╤ ة ╘╤═ ط╟ وع╙ف ┼ط╟ ╟طع╪ف╤µغ ة µ═▀ع ╟╬╨
╟طع╒═▌ ط╚ط╟╧ ╟ط▀▌╤ ة ═▀ع غ╩▌ ╟ط═╟╠╚و
  Duration: 01:02:27.01, start: 0.000000, bitrate: 16 kb/s
    Stream #0:0: Audio: sipr (sipr / 0x72706973), 16000 Hz, mono, flt, 16 kb/s
Output #0, mp3, to '001.mp3':
  Metadata:
    TIT2            : ╟ط╘╤و╪ ╟ط├µط
    author          : ╟ط╘و╬ ع═ع╧ غ╟╒╤ ╟ط╧وغ ╟ط├ط╚╟غو
    TCOP            : www.islamway.com
    comment         : ╟ط╟═╧╟╦ ▌و ╟ط╧وغ µ╟ط╚╧┌╔ - µ╟ط╙غ╔ µ╟╩╚╟┌ ╙غ╔ ╟ط╤╙µط µف╧ه ╟
ط╙ط▌ ة ═▀ع ط╚╙ ╟ط╬ع╟╤ ▌و ╟طµ▐╩ ╟ط═╟طو ة µ═▀ع ╩█╪و╔ ╟طµ╠ف µ╟ط▀▌وغ ة ═▀ع ط╚╙ ╟ط┼و╘
╤╚ ة ط╚╙ ╟ط▀┌╚ ╟ط┌╟طو ة فط و╠µ╥ ╙╚ ╟ط▀╟▌╤ ة ╘╤═ ط╟ وع╙ف ┼ط╟ ╟طع╪ف╤µغ ة µ═▀ع ╟╬╨
╟طع╒═▌ ط╚ط╟╧ ╟ط▀▌╤ ة ═▀ع غ╩▌ ╟ط═╟╠╚و
    TSSE            : Lavf56.40.100
    Stream #0:0: Audio: mp3 (libmp3lame), 16000 Hz, mono, fltp, 16 kb/s
    Metadata:
      encoder         : Lavc56.48.100 libmp3lame
Stream mapping:
  Stream #0:0 -> #0:0 (sipr (native) -> mp3 (libmp3lame))
Press [q] to stop, [?] for help
001.rm: Input/output error:53.46 bitrate=  16.0kbits/s
size=    7336kB time=01:02:27.00 bitrate=  16.0kbits/s
video:0kB audio:7335kB subtitle:0kB other streams:0kB global headers:0kB muxing
overhead: 0.007988%

the output file shows duration of

% ffmpeg.exe-i 001.mp3
ffmpeg version N-73648-g90dd6ad Copyright (c) 2000-2015 the FFmpeg developers
  built with gcc 4.9.2 (GCC)
  configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-av
isynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enab
le-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --
enable-libdcadec --enable-libfreetype --enable-libgme --enable-libgsm --enable-l
ibilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enab
le-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --en
able-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --ena
ble-libtwolame --enable-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc
 --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enabl
e-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-lzma --ena
ble-decklink --enable-zlib
  libavutil      54. 28.100 / 54. 28.100
  libavcodec     56. 48.100 / 56. 48.100
  libavformat    56. 40.100 / 56. 40.100
  libavdevice    56.  4.100 / 56.  4.100
  libavfilter     5. 21.100 /  5. 21.100
  libswscale      3.  1.101 /  3.  1.101
  libswresample   1.  2.100 /  1.  2.100
  libpostproc    53.  3.100 / 53.  3.100
[mp3 @ 0437c920] Skipping 0 bytes of junk at 600.
Input #0, mp3, from '001.mp3':
  Metadata:
    title           : ╟ط╘╤و╪ ╟ط├µط
    author          : ╟ط╘و╬ ع═ع╧ غ╟╒╤ ╟ط╧وغ ╟ط├ط╚╟غو
    copyright       : www.islamway.com
    comment         : ╟ط╟═╧╟╦ ▌و ╟ط╧وغ µ╟ط╚╧┌╔ - µ╟ط╙غ╔ µ╟╩╚╟┌ ╙غ╔ ╟ط╤╙µط µف╧ه ╟
ط╙ط▌ ة ═▀ع ط╚╙ ╟ط╬ع╟╤ ▌و ╟طµ▐╩ ╟ط═╟طو ة µ═▀ع ╩█╪و╔ ╟طµ╠ف µ╟ط▀▌وغ ة ═▀ع ط╚╙ ╟ط┼و╘
╤╚ ة ط╚╙ ╟ط▀┌╚ ╟ط┌╟طو ة فط و╠µ╥ ╙╚ ╟ط▀╟▌╤ ة ╘╤═ ط╟ وع╙ف ┼ط╟ ╟طع╪ف╤µغ ة µ═▀ع ╟╬╨
╟طع╒═▌ ط╚ط╟╧ ╟ط▀▌╤ ة ═▀ع غ╩▌ ╟ط═╟╠╚و
    encoder         : Lavf56.40.100
  Duration: 01:02:35.59, start: 0.069063, bitrate: 16 kb/s
    Stream #0:0: Audio: mp3, 16000 Hz, mono, s16p, 16 kb/s
At least one output file must be specified

original: 01:02:27.01
output: 01:02:35.59

files are at:
​http://maknoon.com/audios.mp3/alalbani/alnoor/001.mp3
​http://maknoon.com/audios.mp3/alalbani/alnoor/001.rm

this is affecting seek since i got two different points in the file.

[Carl Eugen Hoyos]

I tested the following:

$ time realplay -q 001.rm

This reports a length of 1:02:33 for the input file which seems closer to what FFmpeg produces than what the file header reports.