Whenever I connected my TV to my MacBook Pro it always had a red / pink colour tint which made it unwatchable for video and unusable as an external display. People say its due to bad cables and HDMI ports in your TV and thats not actually true.
I finally figured out what the issue was and its not what you might expect. Follow these steps and you will have it working in minutes. The same will work for connecting a PC to a TV but you will have to do it through control panel and the displays menu in there.
Open System Preferences under the Apple icon in the top left
And thats it, enjoy!