Audio resampler only works with 16 bits per sample. patch welcome.

After some searching it seems this is related to a known bug which was apparently fixed in February 2009. I set out to find a newer ffmpeg.exe (which is what WinFF calls to do the actual conversion). I found some Win32 builds of ffmpeg here but found that they all claimed to not know the “libfaac” codec. After some more digging I learned that libfaac (the audio codec for MP4 for iPod/iPhone) is no longer considered free software and was dropped from the repository in mid-April. Fortunately there were older builds available, and I grabbed the one dated 2009-04-01, extracted the ffmpeg.exe into my WinFF directory and voila, it worked.

Old ffmpeg.exe:

C:\Documents and Settings\Evan>"C:\Program Files\WinFF\ffmpeg.exe" -version
FFmpeg version SVN-r15986, Copyright (c) 2000-2008 Fabrice Bellard, et al.
  configuration: --extra-cflags=-fno-common --enable-memalign-hack --enable-pthr
eads --enable-libmp3lame --enable-libxvid --enable-libvorbis --enable-libtheora
--enable-libspeex --enable-libfaac --enable-libgsm --enable-libx264 --enable-lib
schroedinger --enable-avisynth --enable-swscale --enable-gpl
  libavutil     49.12. 0 / 49.12. 0
  libavcodec    52. 6. 0 / 52. 6. 0
  libavformat   52.23. 1 / 52.23. 1
  libavdevice   52. 1. 0 / 52. 1. 0
  libswscale     0. 6. 1 /  0. 6. 1
  built on Dec  3 2008 01:59:37, gcc: 4.2.4
FFmpeg SVN-r15986
libavutil     49.12. 0 / 49.12. 0
libavcodec    52. 6. 0 / 52. 6. 0
libavformat   52.23. 1 / 52.23. 1
libavdevice   52. 1. 0 / 52. 1. 0
libswscale     0. 6. 1 /  0. 6. 1

New ffmpeg.exe:

C:\Documents and Settings\Evan>"C:\Program Files\WinFF\ffmpeg.exe" -version
FFmpeg version SVN-r18306, Copyright (c) 2000-2009 Fabrice Bellard, et al.
  configuration: --enable-memalign-hack --prefix=/mingw --cross-prefix=i686-ming
w32- --cc=ccache-i686-mingw32-gcc --target-os=mingw32 --arch=i686 --cpu=i686 --e
xtra-cflags=-fno-common --enable-avisynth --enable-gpl --enable-zlib --enable-bz
lib --enable-libgsm --enable-libfaac --enable-pthreads --enable-libvorbis --enab
le-libmp3lame --enable-libopenjpeg --enable-libtheora --enable-libspeex --enable
-libxvid --enable-libfaad --enable-libschroedinger --enable-libx264
  libavutil     50. 2. 0 / 50. 2. 0
  libavcodec    52.22. 3 / 52.22. 3
  libavformat   52.32. 0 / 52.32. 0
  libavdevice   52. 1. 0 / 52. 1. 0
  libswscale     0. 7. 1 /  0. 7. 1
  built on Apr  2 2009 03:25:40, gcc: 4.2.4
FFmpeg SVN-r18306
libavutil     50. 2. 0 / 50. 2. 0
libavcodec    52.22. 3 / 52.22. 3
libavformat   52.32. 0 / 52.32. 0
libavdevice   52. 1. 0 / 52. 1. 0
libswscale     0. 7. 1 /  0. 7. 1

This also works great for encoding videos to XviD, which shrinks them to about 10-20% of their original size, making it much faster (in some cases, possible) to upload them to sharing sites.