I have a sony walkman. Instead of an ipod. I run pclinuxos. I use download helper to convert music to MP3's. But I can't seem to do the same with video. I've tried MPEG-4 , mp4, wmv, .Sony says it uses mp4. Sony says I have to get some sort of software from their site. Am I using the wrong extension or running into some sort of DRM. thank you.