In keeping with our reports and rants on the ‘interesting’ world of HDMI, here are more observations I’ve made along with facts via e-mail and phone calls with Bob Rappaport at PureLink, HDMI tech support and the DTS Pro Audio division. This may help you with any dropped signals you’ve had thus far.

Working Within HDMI Protocol Boundries & Words On 1.3

Dave Long | Evolution Audio Video Inc.

Working Within HDMI Protocol Boundries & Words On 1.3
Dave Long, Evolution Audio Video Inc.,

In keeping with our reports and rants on the 'interesting' world of HDMI, here are more observations I've made along with facts via e-mail and phone calls with Bob Rappaport at PureLink, HDMI tech support and the DTS Pro Audio division. This may help you with any dropped signals you've had thus far.


I've been playing with the up-converting KiSS DP-600 at home, for about 9 months now. It's connected into my Loewe Planus this way I take the HDMI 1080i output from the KiSS unit that goes into a PureLink HDMI Switcher. That switcher (HDS-41R now replaced with newer configured switchers) has always worked flawlessly and also has my PS3 running HDMI into it-also at 1080i. From the HDMI output of the PureLink, it goes to DVI, uses the older PureLink DVI to VGA HDCP compliant adaptor, then VGA into a Neoya X-Box VGA switcher and finally VGA into the Loewe. Now the reason I explain all this is to make a point when I turn on the system I have a specific order I follow. Protocols that my system needs, to kick into gear and if I don't follow the rules, I can get a blank stare from the Loewe. I thought this was just a quirk within the Kiss unit but that just isn't so. It's really an HDMI-HDCP handshake issue and Bob Rappaport of PureLink confirms that these protocols are absolutely necessary if you want to ensure a picture whether you're doing multiple store displays or installing a system down the road from you, so this process, will alleviate any sporadic signal stoppages as well as tantrums.

First, I turn on the display and make sure I have the correct input and resolution selected. The PureLink and Neoya are constantly powered but I make sure the PureLink switcher is set to the correct source and the Neoya VGA switcher is set properly. Then I turn on the source. I found that if I do this the other way 'round, the source unit can and usually will, kick the signal back into itself because it has nowhere to go. It hits a brick wall and bounces back. That's a problem because once it does that, it's a pain (and at times impossible) to reboot correctly. The Kiss unit-and this is also true of many HD-DVD & Blu-Ray players pushing HDCP especially at 1080p, can shut down that output as a defense mechanism. The display MUST be on and open to accept the signal. In some cases, end users have been watching a Hi-Def DVD and while it's still running, will switch the display's input to something else like satellite then back to the HDMI input only to find the source has shut down that hi-way. HDMI says that's usually the EDID firmware in the display. Here's more on that usually, an HDMI/HDCP source only has a limited amount of times it will try to do the handshake and then it shuts the port off. You put up a brick wall when you change inputs. The signal has nowhere to go and it closes. If you're going to change inputs, stop the DVD HD player. Put simply, the display and source have to talk to each other and that dialogue needs to be on-going and precise. This back and forth lingo can't work if one party can't hear. You very likely won't have as many pieces in between your source and display as I do but you'll find you're still better off turning your source on, last. This is also true with a receiver in the middle. It's like driving your car into the garage. Unless you open the damn door first, you're going to do some serious damage. Open the door THEN drive in. When you shut off your equipment reverse the process and power down the display LAST.

Since virtually all Hi-Def HDMI output source devices require firmware updates periodically, you should make sure your source has the latest. Those updates can be little things they can be big. The PS3 has had about 7 since released. They're not made available because the manufacturers screwed up to begin with but rather, they knew this technology was in it's infancy that the medium would evolve and how irked would you be if the updates weren't possible but you instead had to buy new equipment? That wont fly any longer because of the frequency of firmware changes, hence the ability to update. So brass tacks, you can't really think of the signal any longer, as a simple linear analog path. You have to out-think the HDMI and once you do, once you understand the HD path and it's protocols, 1080i/p with HDCP becomes a no-brainer. If you have a customer's system powering up one thing at a time or all at once, you'd best re-configure that sequence or you'll be getting calls late at night from panting customers and they won't ask what you're wearing.

As far as 1.3 goes, this is a version that arguably has narrow appeal and not nearly as critical as everyone believes. It may well be preferable but certainly not a gory painful death if you can't go there. It assumes the source rez will go up from 1080p at some point, and as such, may have an even higher colour count but by the time resolution goes up, it's safe to assume version 1.4 will be there. It's important to note by the way, that even HDMI has resolution limits and not boundless bandwidth like many would like to think. Version 1.3 also carries auto-lip-synch since some displays seem to be periodically thrown off, making some movies look like they were badly dubbed in someone's garage (usually the fault of receivers). If your source material has more colour shades in it, 1.3's 'Deep Color' and/or 'xv.Color', will take advantage of that and at the same time reduce some of that 'banding' of shade differences caused by the binary language of Digital. An example would be an evening sky where the shades of orange & yellow are not graduated but look more like stripes.

The audio carried by HDMI seems a bit confusing right now because ear-candy like DTS-HD Master Audio, and Dolby True HD can only be run through HDMI, not Toslink or Co-ax but the fine gent I talked to at DTS via phone and e-mail, added that their backwards compatible core can be decoded at 1.509Mbps by your legacy receiver. That's pretty much the highest your current receiver can do depending on the manufacturer. That, is still greater than what you've been pushing with standard DVD which was encoded pretty much with 758kbps-usually to save space. This is why, when you hear 'regular' DTS (or possibly DD as well but this is not confirmed), on your current system from Blu-Ray or HD-DVD, the voices are more distinct, the LFE is tighter not as muddied and your steering tends to be a bit more precise. I've definitely confirmed that on my setup at home.

According to the DTS website, Blu-Ray's HD audio capacity has a higher ceiling for the new 'Hi-Definition' audio than HD-DVD. How much higher? Well, with Blu', the site states 24.5Mbps per HD Master Audio compared to 18.0 on HD-DVD. The DTS High Resolution Audio is 6.0Mbps on Blu and just 3.0 on HD-DVD. That's not a choice, it's simply the space restriction on the latter format. The other important thing to note about the new HD audio formats, is that you DON'T necessarily need HDMI 1.3 to carry them. My contact at HDMI says all previous versions of HDMI will carry the new HD audio paths. DTS on the other hand says that's not entirely true. DTS says more specifically, that if the PCM output is used, the DTS-HD can be run through analog outputs but add, earlier versions of HDMI were tested in their labs and as a result, any previous version of HDMI other than 1.3, will NOT carry DTS-HD via bitstream. That, you need 1.3 for. Since HDMI's inception, it's always been able to pass 8 channel 192khz/24 bit but the boys at HDMI add that if you want your AV receiver to perform the decoding INSTEAD of your source such as a Blu-Ray player, 1.3 will be necessary. DTS agrees.

So, one might surmise that much like early DVD players and post-ProLogic receivers, who you actually let do your decoding will in most probability, be moot. Everyone wants the newest form of digital and will likely end up letting the receiver do the work via HDMI 1.3. because it's the easiest route and that, is what the boys at HDMI and the receiver manufacturers prefer you to do. However, you know that running long lengths of HDMI can be fatal. At 1080p running 50ft or more can result in speckles, dimness or even no picture at all. So now that you'll be running HDMI cables from your sources to your receiver/switcher then one or two to the display, depending on length, real Fiber Optic cables will become more of a necessity. If long lengths have the uncanny ability to lose signal strength, it stands to reason the HDCP handshaking will become rather limp-wristed at best and for long lengths of HD, copper will go the way of the Dodo. (By the way, despite reports of the theoretical ability to run 1080p via Component, advocates forget about the audio side of things. HDMI was introduced to pass HDCP & HD audio). So, now I can work with HDMI and it's parasitic ally HDCP because I work around that sensitive connection. Once made I don't budge it and more to the point, I always remember to open the garage door before I drive the car in. I get it.


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