Onkyo 876 with hdmi from blu-ray sound is fantastic video poor

Please note i have had to use the wrong product details in the Product box as there is no defualt for a 876 and it will not let me enter it as a valid product?. My new tx -sr 876 is wonderfull sound wise but when passing video through and then back to tv via hdmi the picture is far worse than when I run the hdmi direct from the blu-ray player to the tv, I have tried this and used the optical to send sound to the onkyo but opyical will not support dts master audio etc, I have even got an hdmi splitter and split the signal into two - one to the tv and the other to the onkyo, when I do this there must be some sort of compatibility problem as the onkyo has only once let this process work on all the other occasions it will not play master audio and only 5.1 dts/ dolby just as if it were connected to optical or coax! also the picture quality via the spliter is just as poor. Also when I connect HDMi to the onkyo and set the blu-ray to 24 fps the onkyo closes down and the blu-ray player reverts back to 60fps - but when i connect the blu-ray direct to the tv and do this it asks me if i want to keep the settings which is what it should do. Now I am realy pulling my hair out - I have tried everything I can think of ( but I am no expert) is there any settings on the onkyo that i should alter or have I purchased somthing that had a lot of hype but in fact is not realy up to the job? Any help that you can give would be so very greatfully appricated. Simon.