The mini's working just fine with the HDMI to Component Video adaptor:
Before I plugged everything together I made sure to set up my mini for Screen Sharing. I did this as the HDMI to Component converter supports 1080p, but my TV only supports 1080i, and I expected the Mac to default to the "best resolution" it's been told about - which it did. By remoting in I was able to change Display Preferences:
The Underscan setting is very important for CRT and projection based TVs as they're normally set so that the picture goes beyond the edges of the screen (known as overscan). While fine for television shows, it causes problems with computers as import information (like the menu bar) can end up offscreen. Adjusting underscan lets you compensate for the TV's overscan.
My DirecTV box worked just fine when I plugged it into the 2nd HDMI port of the convert box. I was a little surprised that it kept the "allowed resolutions" I'd previously set for my HDTV (it supports 480i, 480p and 1080i) and didn't auto adjust it's settings when I switched from using Component Video to HDMI.
Streaming from Syfy's website works as well, though it did take a little bit to get the audio1 to work correctly:
And yes, I can full-screen the streaming video. The picture quality was decent, though the audio is "just" stereo (and I remember being quite excited when stereo TV first showed up in the 80s).
I've also installed AirServer and can now use the mini to wirelessly show things from my iPad and iPhone - it's just like using AirPlay on the Apple TV. I've tried it out with videos, photos and games.
I did discover that EyeTV 3 is not happy if it's displaying video and the HDMI box is switched to the DirecTV box - EyeTV ended up crashing in the middle of recording tonight's episode of The Big Bang Theory. Luckily my DirecTV box was tuned to that channel so I was able to rewind its live tv buffer and watch the entire episode. I'll just have to make sure to close any TV windows before switching over to the DirecTV box - and I'll only be doing that for another couple weeks, so it's just a short-term concern.
1the audio was initially being routed to the mini's built in speaker instead of going through the HDMI cable to the surround sound receiver. I found this post over at Apple's Discussions, about creating an Aggregate Device, so I ran Audio MIDI Setup (in the OS X Utilities folder) and set one up.
I then made sure the Aggregate Device was selected in Sound Preferences. It didn't work right away, but it did after I rebooted the mini.