after messing around with ffmpeg i found the correct switches to do this.

for anyone else wanting to do the same here are the command line args:

single jpg:
ffmpeg.exe -y -i <source.jpg> -vcodec mpeg2video -pix_fmt yuv422p -aspect 4:3 output.m2v

sequence of jpgs:
ffmpeg.exe -y -i <source%d.jpg> -vcodec mpeg2video -pix_fmt yuv422p -aspect 4:3 output.m2v