[FFmpeg-user] MPEG-4 Video Enoding - different outputs on different machines

[Forsale Zhangjiang]

Hello Experts,
 
I used FFmpeg to encode video into MPEG-4 video format, and got different outputs on different machines. My coomand is: 
ffmpeg.exe -i "abc.avi" -vcodec mpeg4 -r 65535/4369 -b 750000 -an -f m4v "abc.m4v"
 
The version information is:
ffmpeg version N-32611-gd55b06b, Copyright (c) 2000-2011 the FFmpeg developers built on Sep 15 2011 00:23:27 with gcc 4.6.1
configuration: --enable-gpl --enable-version3 --enable-runtime-cpudetect --enable-avisynth --enable-bzlib --enable-frei0r --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libfreetype --enable-libgsm --enable-libmp3lame --enable-libopenjpeg --enable-librtmp --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxavs --enable-libxvid --enable-zlib
 
It turns out that some of the outputs can be decoded and played, while others have incomplete header information and can not be decoded. 
My question: What is the problem behind this situation and can we force same output on different machines/PC environments? 
 
Many thanks in advance!
 
James