support msn audio

[ami_stuff]

it looks like it's just a gsm_ms

​http://samples.mplayerhq.hu/A-codecs/MSN/msnaudio.asf

here are more samples:

​http://www1.datafilehost.com/d/67f602fc

44khz_mono_71663_baund.avi
22khz_mono_35832_baund.avi
11khz_mono_17916_baund.avi
8khz_mono_13000_baund.avi

decodes ok, the rest of the modes needs some tweaks in the decoder

C:\>ffmpeg -i msnaudio.asf
ffmpeg version N-55393-g3b2e99f Copyright (c) 2000-2013 the FFmpeg developers
  built on Aug  8 2013 21:32:57 with gcc 4.7.3 (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-libcaca --enable-libfreetyp
e --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --ena
ble-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-l
ibopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libsp
eex --enable-libtheora --enable-libtwolame --enable-libvo-aacenc --enable-libvo-
amrwbenc --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxavs --
enable-libxvid --enable-zlib
  libavutil      52. 41.100 / 52. 41.100
  libavcodec     55. 24.100 / 55. 24.100
  libavformat    55. 13.102 / 55. 13.102
  libavdevice    55.  3.100 / 55.  3.100
  libavfilter     3. 82.100 /  3. 82.100
  libswscale      2.  4.100 /  2.  4.100
  libswresample   0. 17.103 /  0. 17.103
  libpostproc    52.  3.100 / 52.  3.100
[asf @ 029d78a0] Estimating duration from bitrate, this may be inaccurate
[asf @ 029d78a0] Could not find codec parameters for stream 0 (Audio: none (2[0]
[0][0] / 0x0032), 22050 Hz, 1 channels, 35 kb/s): unknown codec
Consider increasing the value for the 'analyzeduration' and 'probesize' options
Guessed Channel Layout for  Input Stream #0.0 : mono
Input #0, asf, from 'msnaudio.asf':
  Metadata:
    title           : Scorpion Segment 3
    copyright       : Paramount Pictures
  Duration: 00:05:44.38, start: 0.000000, bitrate: 35 kb/s
    Stream #0:0: Audio: none (2[0][0][0] / 0x0032), 22050 Hz, mono, 35 kb/s
    Stream #0:1: Video: msmpeg4v2 (MP42 / 0x3234504D), yuv420p, 320x240, 36.17 t
br, 1k tbn, 1k tbc
At least one output file must be specified

[Michael Niedermayer]

Patch applied

[ami_stuff]

Replying to ami_stuff:

the rest of the modes needs some tweaks in the decoder

Implemented in 8c87658fdc657fa0c19c9b507645b03d5295eb49 by Kostya.