Are SDI cables backward in a comparison with HDMI 2.1 fiber optics cables?

[Truthler]

Are SDI cables backward in a comparison with HDMI 2.1 fiber optics cables in 8K video transmissions?

[october262]

Are SDI cables backward in a comparison with HDMI 2.1 fiber optics cables in 8K video transmissions?

see here - https://smallhd.com/products/12g-sdi-cable-120

[dellsam34]

SDI cables are backward and forward compatible, If you got one from the early 70's that was used with uMatic machine for composite it will work for 12G with no problems, It will be foolish to pay $100 for a SDI cable. If you are running it for a long distance then get a used brand name cable, Don't buy chinese cables, they are cheap for a reason, they use any kind of cheap materials to make it look like a cable, They have no sol.

[Truthler]

Okay, but fiber optic HDMI 2.1 sounds more trustable technology even for long distances.

SDI can not carry RGB and 4:4:4 colors in high resolutions.....

[dellsam34]

I don't know what the standard can carry but the cable itself can carry any signal up to RGB 4:4:4 as long as it is built to standard 75ohm, The only difference as I said above is for long runs shielding becomes very very importnat, It is easy to drop bits of a high frequency signal due to interference. So that's where the quality of the cable becomes a consideration, For under 6 feet you should be okay.

[Truthler]

I don't know what the standard can carry but the cable itself can carry any signal up to RGB 4:4:4 as long as it is built to standard 75ohm, The only difference as I said above is for long runs shielding becomes very very importnat, It is easy to drop bits of a high frequency signal due to interference. So that's where the quality of the cable becomes a consideration, For under 6 feet you should be okay.

But for the laser beams in fiber optics HDMI 2.1 every bit must arrive ON TIME.

Copper can not provide such speed and safety for the data transmission.

[Cornucopia]

SDI is self-clocking, and hdmi uses tmds along multiple channels for sychronization. Therefor your supposition that either sdi or copper hdmi cannot support things like 8k is ridiculous.

It all comes down to required bandwidth, and distance, and cable architecture and quality.

If you need your signal to travel a kilometer or more, you should use fiber, regardless of whether it is hdmi, sdi, dp, or even vga.

If you need 8k to transfer reasonably small distances (a couple of meters), ANY cable type copper or fiber, and most any quality, of any protocol (hdmi, dp, sdi) will work.

In the in-between (e.g. 10 meters-30 meters), it will depend on all the factors of cost vs quality, ease of running cable vs. infrastructure integration, etc.

But you misunderstand how fiber transceivers work - they have serializers & deserializers built into the couplers or the ports, so there should never be any issue of timing. Unless you are referring to group delay of multiple channels of video used in something like a broadcast uplink truck, and then they would also have either exactly timed length bundles of cables, or they would have inline variable time delay devices to adjust for those interchannel differences.


Scott

[Truthler]

SDI is self-clocking, and hdmi uses tmds along multiple channels for sychronization. Therefor your supposition that either sdi or copper hdmi cannot support things like 8k is ridiculous.

It all comes down to required bandwidth, and distance, and cable architecture and quality.

If you need your signal to travel a kilometer or more, you should use fiber, regardless of whether it is hdmi, sdi, dp, or even vga.

If you need 8k to transfer reasonably small distances (a couple of meters), ANY cable type copper or fiber, and most any quality, of any protocol (hdmi, dp, sdi) will work.

In the in-between (e.g. 10 meters-30 meters), it will depend on all the factors of cost vs quality, ease of running cable vs. infrastructure integration, etc.

But you misunderstand how fiber transceivers work - they have serializers & deserializers built into the couplers or the ports, so there should never be any issue of timing. Unless you are referring to group delay of multiple channels of video used in something like a broadcast uplink truck, and then they would also have either exactly timed length bundles of cables, or they would have inline variable time delay devices to adjust for those interchannel differences.


Scott

If you make a measurement of a still picture (PNG) , you send it trogh the port of a computer via a 30 m long classic SDI and a optical HDMI, and you will compare the same picture on a distant monitor, you will realize after the enlargement, that the copper SDI is not the same (from pixel to pixel), however the picture from the fibre optical HDMI will remain exactly the same as the source.

[dellsam34]

If you make a measurement of a still picture (PNG) , you send it trogh the port of a computer via a 30 m long classic SDI and a optical HDMI, and you will compare the same picture on a distant monitor, you will realize after the enlargement, that the copper SDI is not the same (from pixel to pixel), however the picture from the fibre optical HDMI will remain exactly the same as the source.

Here we go, snake oil science. How the hell a dumb cable decipher digital data pockets and strip out the individual pixels and change them? This is not analog video in a cable, it's digital, It's either you get the entire data or you don't.

[Cornucopia]

Hey dellsam34, don't quote me as him!

No, Truthler, in the digital world there is such a thing as error correction. In your scenario, BOTH would be identical to the source, assuming EC was working as it should. And in the case of SDI, for HD material, it is rated to be good to use out to 100 meters using copper without needing a repeater (which cleans & regenerates the signal).


Scott

[Truthler]

How can both be identical ? Copper could not transfer perfectly all the huge ammount of information. There will be missing pixels or wrong colored pixels... copper is not trustable...you said in an other topic.

Just because a signal is digital, it do not guarantee perfection either.

[dellsam34]

Hey dellsam34, don't quote me as him!

Fixed.

[Cornucopia]

No, Truther, what I said in some other topic, and will say here again is: there is NO perfect medium. All forms of connection and cabling have their weaknesses, and one should always choose the form that best meets the project. Digital or Analog.

Copper is fully "trustable"...up to a point. That point depends on factors as bandwidth/bitrate required (the "burden"), shielding & isolation, cable diameter, materials, and most importantly DISTANCE. Copper use in SDI, for HD material, should be fully "trustable" out to ~100 meters, as per the spec (which is why they put out specs).
Fiber is fully trustable also up to a point, but that point is much longer. In the short distances, you have the option of either, allowing you to factor in other things such as cost. Or the option to transmit inline power (possible with copper, but not yet with fiber).
At very long distances, you can still use Copper, but you then need repeaters.
At VERY VERY LONG distances, you also need repeaters for fiber.

You cannot make a overbroad sweeping statement without conditionals such as "what is the payload burden?" and "what is the distance?" and "what are the environmental factors?".
Words like "THE HUGE AMMOUNT" (sic) have no meaning unless you actually state the amount.


Scott