mhl to hdmi to rca

[AC Question]

im looking to take the mhl to hdmi to rca for the video player in my truck. the guy at best buy said I need to buy a one that needs power. but do I really need it or can I just get the hdmi to rca cable?

 

[B. Diddy]

What resolution is the video player in the truck? If it's standard def, then I'm not sure you'd be able to convert an HD image successfully. You'd be trying to convert a 1920X1080 image to a 640x480 image.