Sorry Im a audio video noob but I assume this means to connect the TV straight to the Directv receiver via HDMI then connect the Directv receiver to the Onkyo by toslink or rca? Or is there a setting in the Onkyo receiver I can change that would allow the video to pass through unchanged? Thanks for the help.
The menu location varies from year to year and model to model but there should be something like "source setup" (make sure you're on Cable/Satellite) and under that something like "picture adjust". Set it for "through" which is no video processing. Generally speaking modern TVs do a better job of upscaling and you won't need the receiver stopping to examine the incoming signal and make adjustments every time you change the channel.
FWIW I have three Onkyo receivers and this is what I did with mine while I has DTV.
While you're in the menus it's also a good time (optional) to make sure that you've set the "listening mode presets" you need to block out about a 1/2 hour and set the presets for each function (DVD, Cable, etc) and match them up. For example Dolby digital should probably be set to default to dolby digital and DTS signals should probably be set to default to DTS. There are a lot of functions and 2 pages of presets for each. That saves having to manually set listening modes all the time. This is a good place to read the manual before getting started.