format factory convert problem

I wanted to convert my rmvb video into MP4, and put it in to my ipod, but every time after convert with format factory and put into the ipod, i found the whole MP4 video is combined with 2 of the same video, Example - 30 min before convert and 60 min after convert. And the 2nd half of the MP4 video is without sound, so can anyone tell me what is happening , and how can i fix this thing, thx.

If there is no way to fix this, then please tell me what other converter that is free, and don't have to 破解 it, because i found 破解 is too much work for me!!

PS. the video thing not just happened in Ipod, it also happened with itunes and quick time player.