I was having trouble streaming m4v movies via aMPdroid. The common theme was that the higher resolution/bitrate/filesize movies just wouldn't start (near-DVD quality 480p). I noticed ffmpeg was only using one of my two cores, so near 50%, and the video player would never move past the first frame. Lower rez movies (kids educational things, old 4:3) would play just fine and ffmpeg uses near 100% cpu.
I tried playing with the -threads parameters in streaming.xml with no difference. On a whim, I downloaded the latest Windows binary from http://ffmpeg.zeranoe.com/builds/. On a bigger whim, I chose the 64-bit one even though MPExtended is all 32-bit. Replaced the C:\Program Files (x86)\MPExtended\Service\Streaming\ffmpeg.exe with the one from \bin in the zip file. Shockingly, not only did it not crash, but it used near 100% CPU and my movies streamed great!
I tried playing with the -threads parameters in streaming.xml with no difference. On a whim, I downloaded the latest Windows binary from http://ffmpeg.zeranoe.com/builds/. On a bigger whim, I chose the 64-bit one even though MPExtended is all 32-bit. Replaced the C:\Program Files (x86)\MPExtended\Service\Streaming\ffmpeg.exe with the one from \bin in the zip file. Shockingly, not only did it not crash, but it used near 100% CPU and my movies streamed great!