http://www.bluejeanscable.com/articles/how-long-can-hdmi-run.htm
On 2015-09-08 Adam Thompson wrote:
http://www.bluejeanscable.com/articles/how-long-can-hdmi-run.htm
OK, so I should be able to do high-rez's at the 10-12' I need. I'm optimistically going to believe my problem is I need a 1.3 or 1.4 version cable, and test that next (have to bug my friend to bring his monitor back). I'll report back!
Some more research:
"1.4 spec, in order for an HDMI cable to be considered high-speed, it must be able to pass 3,840x2,160 pixels at up to 30 frames per second (and 4,096x2,160 at 24 frames per second)."
Using my math-fu that means that the bandwidth that 3840x2160@30 the above says 1.4 can do is MORE than the bw the Dell 2560x1440@60 requires, meaning that a HDMI 1.4 cable should drive the Dell. I'll make sure I obtain a (non-liar) 1.4 cable to test next. Maybe a 6 and a 12, to ensure length isn't a factor.
It's surprising that there's a dearth of info on this stuff on the net. For instance, most video card spec pages (for >1 year old cards at least) don't list the HDMI version supported. I don't think there's a (linux) software way to tell either.
There are ton of people trying to attach 2k and 4k monitors to their existing cards with DVI/HDMI and running into problems.
This seems to be bleeding edge, no info out there, you're on your own territory. I'm a bit annoyed since I'm not even trying to do 4k, just lousy 2k that even 10 year old DVI supports! Grrr.
P.S. The reason I didn't just use DVI is that the new monitor has no DVI! P.P.S. DVI can support 2560x1440 as long as it's dual-link.
The other real gotcha for me is that my workstation is older and many newer PCI-express cards I try don't run in it (no POST). I've seen this with many older boards, not just mine. It's all supposed to be backwards compatible, but in reality it is not. So if I buy a new card with d.port I'd say there's a 75% chance it won't work for me. I would buy a new board too, but my ws is ECC and that means $1k+, not $400 for a guts upgrade. Higher rez isn't worth $1k + monitor price to me: not yet anyway. :-)
It really makes you wonder why manufacturers always seem to want to reinvent the wheel. Why wouldn't they just use 1G Ethernet? It's an established solid technology with readily available connectors and cables. Easy to work with, good over significant distances... You could even plug it into a switch if you need to go further and you could probably leverage Ethernet multi-cast to feed multiple displays over large distances such as in sports bar.
John
On Wed, Sep 9, 2015 at 1:13 AM, Trevor Cordes trevor@tecnopolis.ca wrote:
Some more research:
"1.4 spec, in order for an HDMI cable to be considered high-speed, it must be able to pass 3,840x2,160 pixels at up to 30 frames per second (and 4,096x2,160 at 24 frames per second)."
Using my math-fu that means that the bandwidth that 3840x2160@30 the above says 1.4 can do is MORE than the bw the Dell 2560x1440@60 requires, meaning that a HDMI 1.4 cable should drive the Dell. I'll make sure I obtain a (non-liar) 1.4 cable to test next. Maybe a 6 and a 12, to ensure length isn't a factor.
It's surprising that there's a dearth of info on this stuff on the net. For instance, most video card spec pages (for >1 year old cards at least) don't list the HDMI version supported. I don't think there's a (linux) software way to tell either.
There are ton of people trying to attach 2k and 4k monitors to their existing cards with DVI/HDMI and running into problems.
This seems to be bleeding edge, no info out there, you're on your own territory. I'm a bit annoyed since I'm not even trying to do 4k, just lousy 2k that even 10 year old DVI supports! Grrr.
P.S. The reason I didn't just use DVI is that the new monitor has no DVI! P.P.S. DVI can support 2560x1440 as long as it's dual-link.
The other real gotcha for me is that my workstation is older and many newer PCI-express cards I try don't run in it (no POST). I've seen this with many older boards, not just mine. It's all supposed to be backwards compatible, but in reality it is not. So if I buy a new card with d.port I'd say there's a 75% chance it won't work for me. I would buy a new board too, but my ws is ECC and that means $1k+, not $400 for a guts upgrade. Higher rez isn't worth $1k + monitor price to me: not yet anyway. :-) _______________________________________________ Roundtable mailing list Roundtable@muug.mb.ca http://www.muug.mb.ca/mailman/listinfo/roundtable
I share your frustration, but in this case even gigabit Ethernet doesn't have the bit rate to support HD resolutions. HDMI 1.0 is almost 5 Gb/s, 1.3 is about 10 Gb/s, and 2.0 is about 18. (https://en.wikipedia.org/wiki/HDMI) I suppose they could initially have gone with 10 Gb/s Ethernet, but that would have limited future growth. Not to mention that there'd be tons of support issues with people trying to use cables not rated for anything over 1 Gb/s or even 100 Mb/s. ;-)
More frustrating is the patent encumbrances and associated license fees, and inevitable competing standards to try to avoid these. Or am I mistaken that this was one of the motivations behind DisplayPort?
The price gouging on cables in the early days of the standard, before there was much competition, was another big frustration, but fortunately reasonably short lived.
On 09/09/2015 08:07 AM, John Lange wrote:
It really makes you wonder why manufacturers always seem to want to reinvent the wheel. Why wouldn't they just use 1G Ethernet? It's an established solid technology with readily available connectors and cables. Easy to work with, good over significant distances... You could even plug it into a switch if you need to go further and you could probably leverage Ethernet multi-cast to feed multiple displays over large distances such as in sports bar.
John
Ya, I guess I underestimated the bit rate which explains why they couldn't use ethernet and also why the HDMI distances are so short. It also explains why HDMI extenders are so unreliable.
John
On Wed, Sep 9, 2015 at 12:35 PM, Gilles Detillieux < grdetil@scrc.umanitoba.ca> wrote:
I share your frustration, but in this case even gigabit Ethernet doesn't have the bit rate to support HD resolutions. HDMI 1.0 is almost 5 Gb/s, 1.3 is about 10 Gb/s, and 2.0 is about 18. ( https://en.wikipedia.org/wiki/HDMI) I suppose they could initially have gone with 10 Gb/s Ethernet, but that would have limited future growth. Not to mention that there'd be tons of support issues with people trying to use cables not rated for anything over 1 Gb/s or even 100 Mb/s. ;-)
More frustrating is the patent encumbrances and associated license fees, and inevitable competing standards to try to avoid these. Or am I mistaken that this was one of the motivations behind DisplayPort?
The price gouging on cables in the early days of the standard, before there was much competition, was another big frustration, but fortunately reasonably short lived.
On 09/09/2015 08:07 AM, John Lange wrote:
It really makes you wonder why manufacturers always seem to want to reinvent the wheel. Why wouldn't they just use 1G Ethernet? It's an established solid technology with readily available connectors and cables. Easy to work with, good over significant distances... You could even plug it into a switch if you need to go further and you could probably leverage Ethernet multi-cast to feed multiple displays over large distances such as in sports bar.
John
-- Gilles R. Detillieux E-mail: grdetil@scrc.umanitoba.ca Spinal Cord Research Centre WWW: http://www.scrc.umanitoba.ca/ Dept. of Physiology and Pathophysiology, Faculty of Health Sciences, Univ. of Manitoba Winnipeg, MB R3E 0J9 (Canada)
Roundtable mailing list Roundtable@muug.mb.ca http://www.muug.mb.ca/mailman/listinfo/roundtable
Worse still, after spending another 2 hours looking into it last night, I found that it is incredibly hard to tell what cables are what. Sites say that legally speaking, the HDMI group doesn't let cable vendors label their cables as "1.4" or "2.0". They are only allowed to say "High Speed HDMI", which is near useless in telling you anything.
It turns out that it's not just rez but refresh that has to be factored into your cable purchase. I guess that's a holdover from HDMI's TV focus. TV's are fine with 30fps. Most computer people need 60fps.
For instance, you *need* HDMI 2.0 to do 4k@60. But they can't label their cable as "2.0", so WTF are you supposed to do?
I talked with my reseller rep at Startech and they said none of their HDMI cables are 2.0 even though they loudly exclaim "ultra hd!" and "4k!". He said they are all HDMI 1.4 or 4k@30. Luckily 1.4 will also do my required 2560x1440@60, so in my case 1.4 is good enough. However, if I was super bleeding edge I'd be getting a 4k monitor and then be stuck having to find a 2.0 cable amongst these wacky labeling rules.
C2G's HDMI cables claim to do 4k@60, so there's a safe option... unless they are lying!
P.S. Michael is almost certainly right when he said at the meeting that you have to manually add the 2560x1440 rez into xrandr once you have the correct components in place.
P.P.S. It looks like 2560x1440 is doable with HDMI, just with so many caveats most people can't get it working and switch to DP. I've picked out a cable and a new inexpensive VC that should allow me to get this working. (And vdpau, which I've wanted for a while...) I will report back in a few weeks.
The place I usually go for cables is monoprice.com. They don't mention the HDMI certification level on any of the cables that I randomly clicked on, but they do clearly state "supports 4K @60Hz" on some of them. Unfortunately there is no way to filter only the cables in that category. The information is hidden in the description so you have to click them one-by-one.
Interestingly, it also appears that long HDMI cable lengths are possible (100+ feet) because the cable makes appear to be embedding some kind of extender chip into the cables themselves.
John
On Wed, Sep 9, 2015 at 2:01 PM, Trevor Cordes trevor@tecnopolis.ca wrote:
Worse still, after spending another 2 hours looking into it last night, I found that it is incredibly hard to tell what cables are what. Sites say that legally speaking, the HDMI group doesn't let cable vendors label their cables as "1.4" or "2.0". They are only allowed to say "High Speed HDMI", which is near useless in telling you anything.
It turns out that it's not just rez but refresh that has to be factored into your cable purchase. I guess that's a holdover from HDMI's TV focus. TV's are fine with 30fps. Most computer people need 60fps.
For instance, you *need* HDMI 2.0 to do 4k@60. But they can't label their cable as "2.0", so WTF are you supposed to do?
I talked with my reseller rep at Startech and they said none of their HDMI cables are 2.0 even though they loudly exclaim "ultra hd!" and "4k!". He said they are all HDMI 1.4 or 4k@30. Luckily 1.4 will also do my required 2560x1440@60, so in my case 1.4 is good enough. However, if I was super bleeding edge I'd be getting a 4k monitor and then be stuck having to find a 2.0 cable amongst these wacky labeling rules.
C2G's HDMI cables claim to do 4k@60, so there's a safe option... unless they are lying!
P.S. Michael is almost certainly right when he said at the meeting that you have to manually add the 2560x1440 rez into xrandr once you have the correct components in place.
P.P.S. It looks like 2560x1440 is doable with HDMI, just with so many caveats most people can't get it working and switch to DP. I've picked out a cable and a new inexpensive VC that should allow me to get this working. (And vdpau, which I've wanted for a while...) I will report back in a few weeks. _______________________________________________ Roundtable mailing list Roundtable@muug.mb.ca http://www.muug.mb.ca/mailman/listinfo/roundtable
Brief follow up to this thread; I just noticed a story on engadget that the HDMI 2.0 certification was just launched. So that explains why you couldn't find any 4K certified cables until now.
http://www.engadget.com/2015/10/05/hdmi-4k-certification/
John
On Wed, Sep 9, 2015 at 2:21 PM, John Lange john@johnlange.ca wrote:
The place I usually go for cables is monoprice.com. They don't mention the HDMI certification level on any of the cables that I randomly clicked on, but they do clearly state "supports 4K @60Hz" on some of them. Unfortunately there is no way to filter only the cables in that category. The information is hidden in the description so you have to click them one-by-one.
Interestingly, it also appears that long HDMI cable lengths are possible (100+ feet) because the cable makes appear to be embedding some kind of extender chip into the cables themselves.
John
On Wed, Sep 9, 2015 at 2:01 PM, Trevor Cordes trevor@tecnopolis.ca wrote:
Worse still, after spending another 2 hours looking into it last night, I found that it is incredibly hard to tell what cables are what. Sites say that legally speaking, the HDMI group doesn't let cable vendors label their cables as "1.4" or "2.0". They are only allowed to say "High Speed HDMI", which is near useless in telling you anything.
It turns out that it's not just rez but refresh that has to be factored into your cable purchase. I guess that's a holdover from HDMI's TV focus. TV's are fine with 30fps. Most computer people need 60fps.
For instance, you *need* HDMI 2.0 to do 4k@60. But they can't label their cable as "2.0", so WTF are you supposed to do?
I talked with my reseller rep at Startech and they said none of their HDMI cables are 2.0 even though they loudly exclaim "ultra hd!" and "4k!". He said they are all HDMI 1.4 or 4k@30. Luckily 1.4 will also do my required 2560x1440@60, so in my case 1.4 is good enough. However, if I was super bleeding edge I'd be getting a 4k monitor and then be stuck having to find a 2.0 cable amongst these wacky labeling rules.
C2G's HDMI cables claim to do 4k@60, so there's a safe option... unless they are lying!
P.S. Michael is almost certainly right when he said at the meeting that you have to manually add the 2560x1440 rez into xrandr once you have the correct components in place.
P.P.S. It looks like 2560x1440 is doable with HDMI, just with so many caveats most people can't get it working and switch to DP. I've picked out a cable and a new inexpensive VC that should allow me to get this working. (And vdpau, which I've wanted for a while...) I will report back in a few weeks. _______________________________________________ Roundtable mailing list Roundtable@muug.mb.ca http://www.muug.mb.ca/mailman/listinfo/roundtable
-- John Lange www.johnlange.ca
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Adam Thompson -
Gilles Detillieux -
John Lange -
Trevor Cordes