shorten: support alaw and mulaw
C:\>ffmpeg -i mulaw_wav.shn
ffmpeg version N-79468-ga676c29 Copyright (c) 2000-2016 the FFmpeg developers
built 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-pthreads --enable-memalign-hack --enable-runtime-cpudetect --
enable-cross-compile --enable-static --disable-shared --extra-libs='-lws2_32 -lw
inmm -lpthread' --extra-cflags='--static -I/var/www/users/research/ffmpeg/snapsh
ots/build/include' --extra-ldflags='-static -L/var/www/users/research/ffmpeg/sna
pshots/build/lib' --enable-bzlib --enable-zlib --enable-gpl --enable-version3 --
enable-nonfree --enable-libx264 --enable-libspeex --enable-libtheora --enable-li
bvorbis --enable-libfaac --enable-libxvid --enable-libopencore-amrnb --enable-li
bopencore-amrwb --enable-libmp3lame --enable-libfreetype --enable-libvpx --disab
le-decoder=libvpx
libavutil 55. 22.100 / 55. 22.100
libavcodec 57. 34.102 / 57. 34.102
libavformat 57. 34.101 / 57. 34.101
libavdevice 57. 0.101 / 57. 0.101
libavfilter 6. 42.100 / 6. 42.100
libswscale 4. 1.100 / 4. 1.100
libswresample 2. 0.101 / 2. 0.101
libpostproc 54. 0.100 / 54. 0.100
[shn @ 0x2894020] Format shn detected only with low score of 1, misdetection pos
sible!
[shorten @ 0x2c20060] unknown audio type
Last message repeated 1807 times
[shn @ 0x2894020] decoding for stream 0 failed
[shn @ 0x2894020] Could not find codec parameters for stream 0 (Audio: shorten,
2 channels): unspecified sample format
Consider increasing the value for the 'analyzeduration' and 'probesize' options
Guessed Channel Layout for Input Stream #0.0 : stereo
Input #0, shn, from 'mulaw_wav.shn':
Duration: N/A, start: 0.000000, bitrate: N/A
Stream #0:0: Audio: shorten, 2 channels
At least one output file must be specified
Wontfix.