DisplayPort 2.1b Arriving This Spring With DP80LL Cables

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  • Nuc!eoN
    Senior Member
    • Nov 2012
    • 302

    #31
    How come DisplayPort is suddenly behind HDMI in bandwidth?

    Comment

    • cl333r
      Senior Member
      • Oct 2009
      • 2301

      #32
      Originally posted by anarki2 View Post

      Nah.

      The real reason is that pretty much all TV makers are members of the HDMI consortium. So to them, license fees don't really matter, it's just a matter of accounting, they're moving money from one pocket to the other.
      Thanks for pointing this out, then I shouldn't hold my breath. Too bad.

      Comment

      • Old Grouch
        Senior Member
        • Apr 2020
        • 693

        #33
        Originally posted by DumbFsck View Post
        People talking about using optical could be better informed.

        It is too expensive, the light has to be high quality, fast pulsing, that is expensive and it gets hot, so you must have a way to distribute the heat and possibly actively cool it.

        All of it is undesirable to put in consumer and "cheap" home appliances like TVs.


        SPDIF is VERY different, as that has basically no bandwidth at all (in comparison).
        Hmm, this 40G transceiver for 100M fibre dissipates 1.5 Watts. Admittedly, the price might be a little high.

        40G QSFP+ SR4 100m 850nm MPO Optical Transceiver


        QSFP+ 40G SR4 Transceiver module is a parallel 40Gbps Quad Small Form-factor Pluggable (QSFP) optical module. It provides increased port density and total system cost savings. The QSFP full -duplex optical module offers 4 independent transmit and receive channels, each capable of 10Gbps operation for an aggregate data rate of 40Gbps over 100 meters of OM3 multi-mode fiber.

        An optical fiber cable with an MPO/MTPTM connector can be plugged into the QSFP module receptacle.
        A 100 Gbit/s BiDi Optical Transceiver (Bidirectional, operating at two separate wavelengths, one for send, one for receive, so you need but a single fibre) uses 3.5 Watts. You'll need to download the PDF product spec. to see the number.

        A 200G transceiver from the same supplier operates at 5 Watts

        Price could well be the stopper. Heat management won't be.

        Comment

        • DumbFsck
          Senior Member
          • Dec 2023
          • 328

          #34
          Originally posted by Old Grouch View Post

          Hmm, this 40G transceiver for 100M fibre dissipates 1.5 Watts. Admittedly, the price might be a little high.



          A 100 Gbit/s BiDi Optical Transceiver (Bidirectional, operating at two separate wavelengths, one for send, one for receive, so you need but a single fibre) uses 3.5 Watts. You'll need to download the PDF product spec. to see the number.

          A 200G transceiver from the same supplier operates at 5 Watts

          Price could well be the stopper. Heat management won't be.
          I stand corrected. Thank you.

          Also, apparently HDMI over fibre for like 50gbps can be bought at amazon for 50 quid. Of course I don't know about the quality, but for 100ft, it can't be too bad right?


          So cost must be the reason, maybe their "lack of toughness"/fragility.

          As clearly demonstrated I don't know enough about it to make an educated guess. I could've sworn I read on some discussion of SPDIF people talking about heat. So now I'm not even sure what I do know from what I don't.

          Comment

          • DumbFsck
            Senior Member
            • Dec 2023
            • 328

            #35
            Also, I keep writing "SPDIF" but obviously what I meant was Toslink...

            My bad on that as well.

            Comment

            • Old Grouch
              Senior Member
              • Apr 2020
              • 693

              #36
              Originally posted by DumbFsck View Post

              I stand corrected. Thank you.

              Also, apparently HDMI over fibre for like 50gbps can be bought at amazon for 50 quid. Of course I don't know about the quality, but for 100ft, it can't be too bad right?


              So cost must be the reason, maybe their "lack of toughness"/fragility.

              As clearly demonstrated I don't know enough about it to make an educated guess. I could've sworn I read on some discussion of SPDIF people talking about heat. So now I'm not even sure what I do know from what I don't.
              The limitations on optical connectors could have more to do with the robustness of the actual connectors. What follows is my speculation:

              The diameter of the core of multi-mode fibre is 62.5 micrometres - for comparison, human hair varies in diameter from about 60 to 120 micrometres. The connector needs to align two optically-flat faces of that diameter together, without dust between them, or scratches on the surface. This is routinely done with optical connectors that simply click into place, which is a minor miracle. The interface is easily damaged, and not the kind of thing you want exposed the environment of a laptop in a carrying bag. There's also a minimum bend radius for optical fibre, which can be 20 times the diameter of the fibre+cladding if the fibre is under tension (typically when being installed), which is easy to undershoot and damage the fibre. So while optical fibre has impressive data-carrying capacity, it is not robust in everyday use. TOSLINK™ is very forgiving because its data-carrying capacity is so low.

              Electrical connectors can be designed to wipe themselves clean of dust and surface oxidation when things are connected, and be designed to do so for a certain (high) number of connection-attempts, giving good electrical contacts - doing so on optically-flat optical-fibre surfaces will lead to scratches in no time, If you are doing a 'one-time' install, then optical is a great technology. Continually connecting and disconnecting - no so much.

              HDMI connectors are specified to be able to cope with 10,000 insertions/disconnection cycles. By contrast, typical optical connectors are rated for 500-1,000 cycles.
              Last edited by Old Grouch; 08 January 2025, 04:03 AM. Reason: thin --> thing

              Comment

              • Sonadow
                Senior Member
                • Jun 2009
                • 2276

                #37
                Originally posted by Old Grouch View Post

                The diameter of the core of multi-mode fibre is 62.5 micrometres
                Your information is > 15 years out of date.

                Comment

                • Old Grouch
                  Senior Member
                  • Apr 2020
                  • 693

                  #38
                  Originally posted by Sonadow View Post

                  Your information is > 15 years out of date.
                  How so? Or are you going to say that nobody uses OM1 these days? Yes, OM2,3,4,5 all have core diameters of 50 micrometres. Shrug.

                  Comment

                  • Ferrum Master
                    Phoronix Member
                    • Feb 2024
                    • 113

                    #39
                    Originally posted by DumbFsck View Post
                    So cost must be the reason, maybe their "lack of toughness"/fragility.
                    Never had those fail.

                    ​​​​Certified 8K cables are also thick as finger and break at connector edges as you have to bend them to hide behind the wall, but it is a pain. Optical ones are pretty sleek and elastic.

                    Basically my idea was, without the bull crap complaints, the DACs are already there in the market, around 50€. There are connectors, ICs, just make it standard.

                    Why fooling around with 3d party? Like creating additional market for things that should be there by default.

                    Optical is the way to go.

                    Comment

                    • adriansev
                      Junior Member
                      • Oct 2020
                      • 22

                      #40
                      at this point i wonder why there is not a video card like device (as end-point) connected with some direct output to the tv/monitor and just transport PCIe/CXL to the host device over some standardized fiber cabling with QSFP28 connectors... to much drama and frustrations over doing the same thing as everything in networking (namely moving bits fast over cabling)

                      Comment

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