Originally Posted by w0x0f
I'm starting to suspect that the cable length is leading to marginal signal quality.
According to Wikipedia:
Although no maximum length for an HDMI cable is specified, signal attenuation (dependent on the cable's construction quality and conducting materials) limits usable lengths in practice. HDMI 1.3 defines two cable categories: Category 1-certified cables, which have been tested at 74.5 MHz (which would include resolutions such as 720p60 and 1080i60), and Category 2-certified cables, which have been tested at 340 MHz (which would include resolutions such as 1080p60 and 2160p30). Category 1 HDMI cables are marketed as "Standard" and Category 2 HDMI cables as "High Speed". A cable of about 5 meters (16 ft) can be manufactured to Category 1 specifications easily and inexpensively by using 28 AWG (0.081 mm²) conductors. With better quality construction and materials, including 24 AWG (0.205 mm²) conductors, an HDMI cable can reach lengths of up to 15 meters (49 ft).
It's not just a matter of length, but wire gauge as well. However, I'm not sure if the above quote means that 24 AWG cable only achieves Category 1 up to 15 metres.
Use of active HDMI repeaters can help longer cable runs, however I don't think it lifts Category 1 to Category 2.
Wall plates can contribute to signal loss too, if you are terminating on wall plates and using discrete cables to each device. If you are running Oppo to F-F connector to display with no other intervening connectors, then that would be best and if you replace the F-F connector with a repeater that should improve the situation further.
Deep Colour killing video is the giveaway that your cable's bandwidth is limited, but it's not necessary as Bluray doesn't use it anyway, so turn Deep Colour off. 1080p24 and 1080i60 should have a lower bandwidth than 1080p60, so try to keep to those depending on the source and your cables will thank you.
HDMI 1 always has a longer delay than HDMI 2 because handshaking has to occur with the additional Marvell chip. If your bandwidth is borderline, it's possible HDMI 1 has to repeat handshakes a few times with the display to get it right.Edited by IanD - 2/19/13 at 6:08am