atrac3: fix remuxing of atrac3 in avi

[ami_stuff]

for some reason binary codec doesn't like atrac3 remuxed by ffmpeg

(with my patch "strf" tag is now identical to what is in the input file, but bin codec
still doesn't like the remuxed file and crashes, so maybe something should be changed
in "auds" tag or somewhere else to make the output file compatible with bin codec)

C:\>ffmpeg -i 66k.avi  -acodec copy -vcodec copy out.avi
ffmpeg version N-43803-g2c0b164 Copyright (c) 2000-2012 the FFmpeg developers
  built on Aug 22 2012 02:22:47 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      51. 70.100 / 51. 70.100
  libavcodec     54. 54.100 / 54. 54.100
  libavformat    54. 25.104 / 54. 25.104
  libavdevice    54.  2.100 / 54.  2.100
  libavfilter     3. 13.100 /  3. 13.100
  libswscale      2.  1.101 /  2.  1.101
  libswresample   0. 15.100 /  0. 15.100
  libpostproc    52.  0.100 / 52.  0.100
[mpeg4 @ 0x1ead740] Invalid and inefficient vfw-avi packed B frames detected
Guessed Channel Layout for  Input Stream #0.1 : stereo
Input #0, avi, from '66k.avi':
  Duration: 00:00:00.50, start: 0.000000, bitrate: 348 kb/s
    Stream #0:0: Video: mpeg4 (Advanced Simple Profile) (XVID / 0x44495658), yuv
420p, 160x120 [SAR 1:1 DAR 4:3], 2 tbr, 2 tbn, 2 tbc
    Stream #0:1: Audio: atrac3 (p[2][0][0] / 0x0270), 44100 Hz, stereo, s16, 66
kb/s
Output #0, avi, to 'out.avi':
  Metadata:
    ISFT            : Lavf54.25.104
    Stream #0:0: Video: mpeg4 (XVID / 0x44495658), yuv420p, 160x120 [SAR 1:1 DAR
 4:3], q=2-31, 2 tbn, 2 tbc
    Stream #0:1: Audio: atrac3 (p[2][0][0] / 0x0270), 44100 Hz, stereo, 66 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
  Stream #0:1 -> #0:1 (copy)
Press [q] to stop, [?] for help
frame=    1 fps=0.0 q=-1.0 Lsize=      22kB time=00:00:00.50 bitrate= 359.3kbits
/s
video:4kB audio:7kB subtitle:0 global headers:0kB muxing overhead 95.916587%