video play????

[luxor823]

Okay i am i guess what you would call a newb. I love electronics but have a hard time figuring out where to learn about them. But who Cares about that my real question is...I have windows media player and pocket tv on my ax and i dowload videos to my pc and then transfer them to my ppc. ok but some play with no sound and others dont play.
i basically want to know everything that anyone knows about videos on ppc's.... what format do i need,can i change the format, can i compress videos to fit on the 128 mb cards etc