I believe there are some expensive wireless hdmi devices that work well, but inexpensive one's are probably garbage.
You could try a hdmi->ethernet adapters, then hook it to a powerline (ethernet through your power lines) to avoid drilling holes. So it would go HDMI -> ethernet -> powerline (inside wall outlet) -> powerline (outside wall outlet) -> coverted back to HDMI. There are powerline adapters that work very well for ethernet.





