XMC-1 - HDMI Dual Output to Single HDTV Issue

[johnsanc]

I have a PC, cable box, Apple TV, Xbox 360, and Wii U all connected to my XMC-1 HDMI inputs. I have 2 HDMI outputs to my LG 55LH90. One input is configured for standard AV components and has the display set as 16-235 (Limited), whereas the other is for PC which is set at 0-255 (Full).

Whenever I initially turn on the TV, the cable box and Apple TV will flicker like there are HDMI handshake issues. However I do not get these issues with the Xbox 360, Wii U, or PC. I can resolve the flickering by changing the input on the TV from HDMI 1 to HDMI 2 and back again (or vice versa). The issue occurs on both HDMI inputs and the only way to resolve is to switch to the other and back again.

After a bunch of testing with various cables, input combinations, etc, I believe the issue has to do with how the XMC is handling the dual outputs in both On and Standby modes. When I disconnect one of the outputs to the TV the issue goes away completely.

Anyone else experience anything like this? Any ideas how to resolve or what might be causing it? I found it odd the issue only occurs with my cable box and Apple TV.

[KeithL]

One thing to bear in mind is that the two HDMI outputs on the XMC-1 carry the same signal. Normally the HDMI negotiations would sort things out and the XMC-1 would settle on a signal that was the lowest-common-denominator for both devices it was connected to (it can't send different resolutions or types of signals to each input). However, in your case, we have two outputs connected to two inputs, but with different requirements, but also both on the same device. Much like trying to conduct two negotiations, on the same item, with the same person, at the same time, but using two different phones, I'm sure that the dual connection is causing confusion - which might simply prevent the negotiations from ever completing properly. (The source, the XMC-1, and the TV are trying to settle on one format they all support.)

Quite possibly, by disconnecting one of the TV's inputs, you are allowing the negotiations to complete without the information from that connection - and, perhaps, once the TV has "settled" on which input to "negotiate to", it is content to ignore the other.

Dec 31, 2015 13:51:12 GMT -5 johnsanc said:

I have a PC, cable box, Apple TV, Xbox 360, and Wii U all connected to my XMC-1 HDMI inputs. I have 2 HDMI outputs to my LG 55LH90. One input is configured for standard AV components and has the display set as 16-235 (Limited), whereas the other is for PC which is set at 0-255 (Full).

Whenever I initially turn on the TV, the cable box and Apple TV will flicker like there are HDMI handshake issues. However I do not get these issues with the Xbox 360, Wii U, or PC. I can resolve the flickering by changing the input on the TV from HDMI 1 to HDMI 2 and back again (or vice versa). The issue occurs on both HDMI inputs and the only way to resolve is to switch to the other and back again.

After a bunch of testing with various cables, input combinations, etc, I believe the issue has to do with how the XMC is handling the dual outputs in both On and Standby modes. When I disconnect one of the outputs to the TV the issue goes away completely.

Anyone else experience anything like this? Any ideas how to resolve or what might be causing it? I found it odd the issue only occurs with my cable box and Apple TV.

[johnsanc]

Good point about carrying the same signal. I will see what I can do to limit it to a single input on the TV and change the display settings appropriately instead depending on the source on the XMC-1.