Just take your phone, take the TV out cable and plug it into the TV and watch some video? Good isn’t it? Now pull out the cable and hold it in one hand, and put the phone in the other. Which one is heavier? There’s not much in it. That’s one of the two problems that handset vendors have combined to attack this week, putting their hopes behind the advanced HDMI chip designs of US specialist Silicon Image. The other problem is that video play out uses up the battery on the handset fast, if you take it to a friend’s house to play video. Right now TV out is at a cross roads ‘ lots of phones have it,…