hmmm...4K HDMI cables

[Greg M]

if only I had a 4K projector for my house

at least my cable will support it when it arrives.

 

[Shane Betts]

Oh, 4k is so yesterday;-)

HDMI can be such an annoying "standard" - because there's so many freakin' standards of it. I have yet to get an entire chain of HDMI devices that are all speaking the same language. I mean, they (generally) work but the chain is always reduced to the lowest standard - which somehow always winds up being 1080p 8bit.

 

[Blair S. Paulsen]

As usual it's not what they say, it's what they don't say. Since all signals over HDMI I am aware of are compressed in some way, the resolution limits of a particular bandwidth spec are typically based on things like MPEG-2.
Baseband 1080P over any HDMI cable? Educate me if I'm off base but I would take any numbers of this type with a shovel full of salt - now how about connection integrity after 100 mating cycles...

Cheers - #19

 

[Mark L. Pederson]

High Speed HDMI Cables

The specification of Version 1.4 High Speed Cables is the same as for version 1.3 High Speed Cables with the additional support of the new D-type connector. Cables which passed v1.3c category 2 HDMI cable tests with A and/or C type connectors will pass version 1.4 cable compliance tests.

By definition in version 1.3 of the HDMI Specification, High Speed HDMI Cables, or HDMI category 2 cables, are required for applications operating above 1080i/8-bit/60Hz. This means that even the standard 1080p/8-bit/60Hz (148.5MHz) applications require category 2 cables (340MHz) which can function at data rates up to 3.4Gbps. Cables which function at only 1080p/12-bit/60Hz (222.75MHz) or below can at best be certified only as category one (74.25MHz).

This fact has not changed with the introduction of version 1.4, but with the introduction of new applications (3D and higher resolution TV) which drive the content data rates up towards 3.4Gbps, certified category two cables become more desirable. Future-proofing becomes more important particularly as the price differential between category one and category two cables decreases.

 

[Greg M]

this cable claims 10.2 Gbps and it has a ethernet ch

 

[Stacey Spears]

Since all signals over HDMI I am aware of are compressed in some way... Educate me if I'm off base

Video over HDMI is always uncompressed. (4:2:2, 4:4:4 or RGB) Audio can be either compressed or uncompressed.

 

[Blair S. Paulsen]

Thanks Stacey, I should have known you'd have the scoop.
So, since we have your expertise in the mix here, what is the limit in bit depth and color sub-sampling (or lack of it) that can be supported at 340MHz over a single high-speed / category 2 HDMI cable carrying 4,096 or 3,840 by 2160 rez?
I have been operating under the assumption that to carry 12 bit fully sampled (4:4:4 in common usage) RGB signal at 4,096 by 2,160 would require at least 2 HDMI cables or 2 Display-Port cables or 2 3G SDI cables. Perhaps by implementing fiber rather than copper a number of spigots can actually pass more bandwidth than we are accustomed to.
As a real world example, when we demonstrated 4K instant "dailies" at CineGear last June we sent 8 lanes of SDI out of the Red Rocket Breakout box to the Sony L-560 4K LCD monitor. It's hard for me to imagine that one HDMI cable can carry as much bandwidth as 8 HD-SDI cables, but it would be darn handy.

Cheers - #19

 

[Shane Betts]

I'm not too sure that the HDMI spec actually governs whether or not the signal is compressed. It's just capable of sending up to a theoretical 3Gbs stream of ones and zeros. How that particular stream is configured is more a matter of whatever hardware sits at either end. The convention is that the signal is (generally) uncompressed as the devices that (generally) employ HDMI (generally) have the decoder at the source (send) end and the receiver (generally) has no decoder. Doesn't mean it can't happen. For instance, as I understand it, there would seem to be nothing to stop Red installing a RedRay decoder in their 4k laser projector and have their RedRay player send compressed data streams along a single HDMI cable at 4k.

Of course, that would seem to be a pretty big assumption on the part of whoever made these cables in question. :rolleyes5: 'Scuse me, talkin' out my arse again...