ATI Radeon AIW 7500 poor video capture

I have phoned and emailed ATI regarding poor TV video clip recordings but they have yet to reply after 1 month.Well, i gave up on them and hopefully someone can help me?Only the first video clip is ok but the subsequent ones are very poor with big pixels the size of postage stamps!I noticed that if there was an interval of 10 mins between recordings,then the subsequent ones are ok.But why?I don’t want to record commercials!Any suggestions will be welcomed.