support rifx

[ami_stuff]

plays with sox

​http://www.fileformat.info/format/riff/corion_rifx.htm

C:\>ffmpeg -i rifx.wav
ffmpeg version N-47225-g3860e34 Copyright (c) 2000-2012 the FFmpeg developers
  built on Nov 29 2012 02:24:10 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.  9.102 / 52.  9.102
  libavcodec     54. 77.100 / 54. 77.100
  libavformat    54. 39.100 / 54. 39.100
  libavdevice    54.  3.100 / 54.  3.100
  libavfilter     3. 23.104 /  3. 23.104
  libswscale      2.  1.102 /  2.  1.102
  libswresample   0. 17.101 /  0. 17.101
  libpostproc    52.  2.100 / 52.  2.100
rifx.wav: Invalid data found when processing input

[Carl Eugen Hoyos]

Fixed by Thomas Volkert in 00d7555f