Thanks for reaching out and I'm sorry to hear that you're having an issue with your Chromecast with Google TV. Let's sort this out.
A few questions: have you ever cast before without any video quality issues? Have you tried using the Chromecast on a different TV? Does it show the same behavior? What's the make and model of your TV?
Try these steps:
I haven't heard from you in a while so I’ll be locking this thread if there’s no update within 24 hours. If you're still experiencing problems, please feel free to start a new thread and we'll be happy to help.