I pulled the following from the Magic Lantern Wiki:
"...the HDMI output from the Canon HDMI is limited to 1620x1080 (3:2) while the camera is not recording. When the camera is recording, HDMI output resolution is limited to only 720x480"
I wasn't aware that the hdmi output was different while the camera was recording vs. "live streaming". Does anyone know what the exact specs of the hdmi output are in "live" mode? In my searching, someone posted that it also spits out 4:2:2 in live mode. What??? I thought they were H.264 (4:2:0), but is this maybe just when recording to the SD card?
The wiki didn't specify which Canon, so maybe all of the above is true, just with certain models?