There are a few ways you can handle this.
First off; I have used 50' hdmi cable (active) on multiple avr receivers and did not observe any mayor issues. I have used shorter cables too and over all had no issue with cable.
The most important here is the brand of the hdmi cable you get.
There are many out there but the good companies make sure their cable passes the "hdmi eye" test.
With out getting into too technical discussion, if you get a monster cable something like ultra high speed, or better cable than that, then you will be fine. I do not prefer monster but they are available rather easily from Best Buy Magnolia or B & H Photo. Do get the best you can find.
Second: you can get hdmi trans-coders and not warry over the distance too much. This is more expensive and requires some technical know how. (gefen transcodes, cat6 cable combo)
Finally: there is a new cable (I have not used yet) that is hdmi to fiber cable. This cable apparently can get you farther distance than any other regular cable, even some transcoders.
If you have any more questions ask.
Do not try to save money on the receiver to tv hdmi cable.