HDMI Splitters and Switches - Handshaking Issues - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 3 Old 08-13-2011, 10:23 AM - Thread Starter
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For the past 7 years or so, I have had a centralized whole-house architecture with video and audio matrix switches, and am considering moving from VGA (RGBHV) video to HDMI. Given the extremely high cost of larger HDMI matrix switchers (8x8 and above), I have begun experimenting with combining lower-cost HDMI splitters, followed by HDMI switches (eg, a 1x8 HDMI splitter at each source, connecting to an 8x1 HDMI switch going to each TV). All of this equipment would be placed in a centralized location (very short HDMI cable connections) and then distributed to HDTVs throughout the house (using HDMI extenders over CAT6 for long runs).

The cost of HDMI splitters, switches and extenders (even those that are HDMI 1.3b compliant and claim to support 3D, etc) seems to be significantly (5-10 times) lower than HDMI matrix switches. I would like this infrastructure to support 3D if possible, and have been assuming (but am not certain) that HDMI 1.3b compliance would be sufficient. I am also not certain whether HDCP 1.2 compliance (eg, as opposed to 1.1) is really required.

Apart from the distance issues, my initial concern has been the HDMI handshaking problems (HDCP, EDID, etc). I have even heard (but not verified) that source devices have limited numbers of KSVs, or "key selection vectors," which prevent them from handshaking, eg, with multiple TVs simultaneously).

So, I began by purchasing a single Sewell HDMI (1x8) Splitter (~ $90) and an ATEN HDMI (8x1) Switch (~ $170), and testing them with 2 sources (an Apple TV and a Roku XD/S) and a small 15" HDTV (Coby LEDTV1526). I used some 6' HDMI cables lying around, though I cannot verify whether they are HDMI 1.3b compliant.

Both sources worked fine when connected directly to the TV, and when connected through either the Splitter or Switcher. However, when I connected either source through BOTH (Splitter followed by Switcher), I began to experience problems. Interestingly, the Apple TV worked most of the time, while I have yet to get the Roku to work at all with this configuration.

In all cases, the problem was the same - an intermittent flashing of the picture (and audio), regardless of whether I was playing content (eg, a streaming Netflix movie) or simply displaying the menus. With the Apple TV, I could usually get it to work reliably by power-cycling the Switch, though it was somewhat hit-and-miss. But, once it started working, it continued working even when I switched sources. However, when I reconnected the devices (eg, to different ports), the problem often reappeared.

So, my question is whether this configuration (HDMI Splitter, followed by an HDMI Switch) is likely to ever work. Is the problem HDCP handshaking as I suspect? I did notice that, while both the Splitter and Switch are HDMI 1.3b compliant, the Splitter supports HDCP 1.2, while the Switch only supports HDCP 1.1 (not sure if this is an issue).

I even wonder whether expensive HDMI matrix switches would resolve these issues (eg, as different source devices and HDTVs are connected over time). I would be very interested in finding a better way to troubleshoot these handshaking (or other) HDMI issues. Any suggestions would be greatly appreciated.
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post #2 of 3 Old 08-13-2011, 10:55 AM
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well, you jumped from a "simple test" (source sink direct) to the "whole ting". I think you need to do at least two intermediate tests.... one source thru splitter to two sinks and one source thru switch to one sink. This way you will see if either units are "friendly" with the cables and equipment you are using.

Having said that the odds are "slim to none" that the configuration will work reliably or at all... why do you think the 8X8 matrix switch is so expensive... it IS rocket science.... :-)
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post #3 of 3 Old 08-13-2011, 01:49 PM
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Yes, that's part of the "fun" of HDMI. Even many 8 x 8 matrix switchers won't work all of the time with all equipment. If you continue with your Franken-switcher, I suspect you're going to learn a lot more about HDMI, HDCP and EDID (whether you want to or not).

I have found the (for the most part) HDMI works right away or it doesn't - the exception being if you can change the EDID or you have bad cables. From what you said, I doubt you'll get your double-switch configuration to work for all situations.

HDMI 1.4a is required for the full 3D spec (even though PS3 slim is 1.3c). However, some 1.3c switchers allow 3D pass-thru.

Cables also never use the version number. HDMI cables are either "high speed" or "standard speed".

For more info, I suggest you start reading the archives of this forum and visit the HDMI Org's web site.
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