Different versions of Motion wants different versions of FFMPEG-

motion-20120717_0fb31d6-armv7l-1_SBo.tgz use ffmpeg-2.8.11-armv7l_minimal-1_SBo.tgz
motion-4.0.1-armv7l-ARG.tgz use ffmpeg-3.3-arm-1_SBo.tgz