mp3 24khz (in wav): overreads

[ami_stuff]

This happens only with 24khz mode.

I can hear some distortions.

C:\>ffmpeg -i 24khz_2ch_160kbps.wav -t 2 -f null -
ffmpeg version N-46755-ge70144c Copyright (c) 2000-2012 the FFmpeg developers
  built on Nov 15 2012 02:38:20 with gcc 4.5.0 (GCC) 20100414 (Fedora MinGW 4.5.
0-1.fc14)
  configuration: --prefix=/var/www/users/research/ffmpeg/snapshots/build --arch=
x86 --target-os=mingw32 --cross-prefix=i686-pc-mingw32- --cc='ccache i686-pc-min
gw32-gcc' --enable-w32threads --enable-memalign-hack --enable-runtime-cpudetect
--enable-cross-compile --enable-static --disable-shared --extra-libs='-lws2_32 -
lwinmm -lpthread' --extra-cflags='--static -I/var/www/users/research/ffmpeg/snap
shots/build/include' --extra-ldflags='-static -L/var/www/users/research/ffmpeg/s
napshots/build/lib' --enable-bzlib --enable-zlib --enable-gpl --enable-version3
--enable-nonfree --enable-libx264 --enable-libspeex --enable-libtheora --enable-
libvorbis --enable-libfaac --enable-libxvid --enable-libopencore-amrnb --enable-
libopencore-amrwb --enable-libmp3lame --enable-libvpx --disable-decoder=libvpx
  libavutil      52.  6.100 / 52.  6.100
  libavcodec     54. 71.100 / 54. 71.100
  libavformat    54. 36.100 / 54. 36.100
  libavdevice    54.  3.100 / 54.  3.100
  libavfilter     3. 23.100 /  3. 23.100
  libswscale      2.  1.102 /  2.  1.102
  libswresample   0. 16.100 /  0. 16.100
  libpostproc    52.  1.100 / 52.  1.100
[wav @ 0x1edc3c0] max_analyze_duration 5000000 reached at 5016000
[wav @ 0x1edc3c0] Estimating duration from bitrate, this may be inaccurate
Input #0, wav, from '24khz_2ch_160kbps.wav':
  Duration: 00:00:33.12, bitrate: 127 kb/s
    Stream #0:0: Audio: mp3 (U[0][0][0] / 0x0055), 24000 Hz, stereo, s16, 128 kb
/s
Output #0, null, to 'pipe:':
  Metadata:
    encoder         : Lavf54.36.100
    Stream #0:0: Audio: pcm_s16le, 24000 Hz, stereo, s16, 768 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (mp3 -> pcm_s16le)
Press [q] to stop, [?] for help
[mp3 @ 0x1edcb60] overread, skip -7 enddists: -6 -6
[mp3 @ 0x1edcb60] overread, skip -6 enddists: -5 -5
[mp3 @ 0x1edcb60] overread, skip -9 enddists: -1 -1
[mp3 @ 0x1edcb60] overread, skip -7 enddists: -3 -3
    Last message repeated 1 times
[mp3 @ 0x1edcb60] overread, skip -6 enddists: -2 -2
[mp3 @ 0x1edcb60] overread, skip -6 enddists: -4 -4
[mp3 @ 0x1edcb60] overread, skip -7 enddists: -4 -4
size=       0kB time=00:00:02.01 bitrate=   0.0kbits/s
video:0kB audio:189kB subtitle:0 global headers:0kB muxing overhead -100.000000%

[ami_stuff]

with mono 24khz there is only 1 overread

[ami_stuff]

the same problem can be reproduced with file generated by lame

lame --resample 24000 test.wav

or

lame --resample 24000 -V 0 test.wav

[ami_stuff]

attached better sample

[m.dmt]

I'm also affected by this bug.
To try to narrow it down, I've encoded PCM16 wav with LAME 3.100 at various sample rates and qualities. Out of all valid MP3 sample rates only 24 kHz is affected. If LAME encoding quality (-q) is <= 4, overread messages appear during decoding. If quality is >= 5, these messages do not appear, but distortions can still be heard. mpg123 1.25.10 decodes without audible distortions in both cases.