Do fiber optic HDMI cables add any noticeable input lag?

Ericone

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Hey! I need to buy a fiber optic HDMI cable at 6 meters in order to use my pc with my 4k tv and a controller for gaming. I'm a bit concerned about possible input lag though, as the signal is converted to light in the cable and then back again. What do you guys think? Do i risk increasing input lag? I plan to play Steam games with controller support.
 

vick1000

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Of course there would have to be some lag introduced. How much depends on the efficiency of the adapters at both ends I would assume. Whether or not they are usable for gaming would probably depend on your overall input lag, as it's a system wide cumilative effect. A repeater/ booster would be a cheaper experiment. Or just active copper cables. Since there is no signal conversion going on. Have not seen any in 2.1 though.
 
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Ericone

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Thanks. Whats the difference between active copper cables and fiber optical? Is there less of a conversion going on?
 

vick1000

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Copper just amplifies the signal I believe. As long as it's just an amplified cable, not an adapter (like Displayport to HDMI, etc...).
 

DanNeely

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Copper just amplifies the signal I believe. As long as it's just an amplified cable, not an adapter (like Displayport to HDMI, etc...).
AFAIK, at least at shorter lengths, it's less amplification than it is cleaning up the signal quality as soon as it enters the cable, and just before it leaves the cable. The mm or so of cable plug contacts on each end of the cable add a lot more degredation to the signal than all the wire between them. Just fixing that up gets you a lot more usable range. If you were looking at a 30m cable to run a projector in a large conference room; then they probably would need to run mid-cable signal boosters as well.
 

hajalie24

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No. I have a 50ft fiber optic hdmi cable and absolutely no issues and I would honestly have no hesitation getting a 100ft hdmi 2.1 cable if I needed it.

It's fiber optic so all these comments regarding copper degradation don't make any sense. Since it's HDMI and very low voltage (if any) it really just needs to be able to send data at the right throughput which is why fiber optic is perfect without needing amplification, etc.
 

Bowman15

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For 20 feet you should go fiber for 4K. Copper HDMI starts to degrade even at 15 feet. Even though it is more expensive its the right choice.
 

TheSlySyl

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Fiber optic cable moves data literally at the speed of light. There won't be any lag no matter the distance.

They use Fiber Optic cables to cross oceans.

The adapters would produce less lag than other sources as long as you get high quality cables.
 

Bowman15

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Fiber optic cable moves data literally at the speed of light. There won't be any lag no matter the distance.

They use Fiber Optic cables to cross oceans.

The adapters would produce less lag than other sources as long as you get high quality cables.

Bingo...
 

vick1000

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Fiber optic cable moves data literally at the speed of light. There won't be any lag no matter the distance.

They use Fiber Optic cables to cross oceans.

The adapters would produce less lag than other sources as long as you get high quality cables.
The signal has to be converted to light impulses and back to electrical though, by an adapter, at both ends. Transmission once converted, is not the problem.
 

Bowman15

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The signal has to be converted to light impulses and back to electrical though, by an adapter, at both ends. Transmission once converted, is not the problem.

The bottom line is light is faster than an electric pulse. If you want the same or lower lag at longer distances while allowing minimal signal degradation such as the best color, HDR, etc.. vs. standard copper then you want fiber HDMI.
 

Bowman15

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Its digital, so you either have signal, mate, or you dont. Color does nt degrade mate! Once you start losing sense of what the signal was, it'll go gobble-garble nd.......poof😁"no input signal"

Call it what you want but longer the longer an HDMI cable is the more signal it loses due to attenuation. It can have a real impact on the quality of audio and video you hear and see at the other end. Look at some video comparisons of HDMI copper vs HDMI fiber over long runs.
 

defaultluser

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The bottom line is light is faster than an electric pulse. If you want the same or lower lag at longer distances while allowing minimal signal degradation such as the best color, HDR, etc.. vs. standard copper then you want fiber HDMI.
only inside a vacuum.

https://www.blog.adva.com/en/speed-...ding-block-low-latency-trading-infrastructure

in fiber, it's around 2/3rds the sped of light in Copper (you trade speed for signal stability). That's why high-frequency traders tend to favor Ethernet or Microwave connections.
 

vick1000

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Call it what you want but longer the longer an HDMI cable is the more signal it loses due to attenuation. It can have a real impact on the quality of audio and video you hear and see at the other end. Look at some video comparisons of HDMI copper vs HDMI fiber over long runs.
Again, the question was about input lag. You can put as many boosters in a chain of copper cables that you need to mantain signal strength.
 

vick1000

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No need with fiber.
So are you saying there is no lag introduced by the adaptation of the signal to light and back? I doubt that is the case, and I doubt a strobing laser is faster than electrons anyway. Transmission speeds are not relavant at such short distances (100ft or less).
 

Bowman15

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So are you saying there is no lag introduced by the adaptation of the signal to light and back? I doubt that is the case, and I doubt a strobing laser is faster than electrons anyway. Transmission speeds are not relavant at such short distances (100ft or less).

That is my understanding from looking at testing over longer distances. Don't care if you doubt it or not...

http://www.fiber-optic-tutorial.com/latency-whats-differences-fiber-copper.html

Here is a pic I found.

ZeroLagHDMIOptical.jpg
 

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Bowman15

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Well the article is regarding NIC protcols, which may or may not be relavent. The pic could be relavent if we knew the source.

Um, google it yourself then, the info is out there. Some forum expert says he doesn't think so and now pics lie. Yeah I'm out....
 

vick1000

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Um, google it yourself then, the info is out there. Some forum expert says he doesn't think so and now pics lie. Yeah I'm out....
Pics lie? Someone just shopped a logo over a pic of a monitor. How do we know the context? I have not been able to find anything in search engines to confirm or deny, which is why I asked for your source. I suspect you have not found anything either, thus a random image search yeilding a result, probably from someone selling that brand of cable. Not my fault you spent extra on a placebo. I have found data to support that copper with switches and/or boosters, does not add input lag, even at 100+ feet.
 

Bowman15

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Pics lie? Someone just shopped a logo over a pic of a monitor. How do we know the context? I have not been able to find anything in search engines to confirm or deny, which is why I asked for your source. I suspect you have not found anything either, thus a random image search yeilding a result, probably from someone selling that brand of cable. Not my fault you spent extra on a placebo. I have found data to support that copper with switches and/or boosters, does not add input lag, even at 100+ feet.

LOL to be fair it is hard to find any references to lag vs. attenuation but they are out there. And I got that pic from an article (reviewer testing some $180 fiber cable) ...I can search again but you are not worth it. I'm sure you can find references proving me wrong with that expertise of doubt?
 

vick1000

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LOL to be fair it is hard to find any references to lag vs. attenuation but they are out there. And I got that pic from an article (reviewer testing some $180 fiber cable) ...I can search again but you are not worth it. I'm sure you can find references proving me wrong with that expertise of doubt?
Right, just as I suspected, and excuses old as the web itself. Just take your word for it 'cause.....reasons. I bet you spend tons of money on speaker cable too, or maybe even DACs with vacuum tubes.
 

Bowman15

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Right, just as I suspected, and excuses old as the web itself. Just take your word for it 'cause.....reasons. I bet you spend tons of money on speaker cable too, or maybe even DACs with vacuum tubes.

LOL so you have nothing...though so. I provided info and the first reply is FAKE! If I found it using Google but you can't yeah that tells me a lot. Go be a forum expert somewhere else.
 

BinarySynapse

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While electrons moving through a wire are slow (very very slow), they’re not the carriers for the signal. In a high frequency signal electrons don’t actually move more than a few microns before being pulled back the other way (on average). So they wouldn’t make very good signal carriers.

It’s the EM wave propagating along the outside of the the conductor that transfers the signal, and its speed depends on the characteristics of the insulator (.95c for air or .6-.8c for typical insulators).


Light travels about .7c through a glass fiber optic cable. However because of internal reflections, the signal effectively travels 1-5% further than the linear length of the cable, making copper cables of the same length potentially faster (though in a 100m cable, it’s only a difference of maybe a few nanoseconds).


Anything that converts light to electricity or electricity to light is going to induce a signal delay. Whether or not it affects your experience depends on how that conversion is happening. Using the electrical signal to drive an LED isn’t going to be noticeable. Consuming a data packet from the copper and retransmitting it as light (possibly re-encoded for better performance in the different medium), could induce a noticeable delay.
 

Bowman15

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While electrons moving through a wire are slow (very very slow), they’re not the carriers for the signal. In a high frequency signal electrons don’t actually move more than a few microns before being pulled back the other way (on average). So they wouldn’t make very good signal carriers.

It’s the EM wave propagating along the outside of the the conductor that transfers the signal, and its speed depends on the characteristics of the insulator (.95c for air or .6-.8c for typical insulators).


Light travels about .7c through a glass fiber optic cable. However because of internal reflections, the signal effectively travels 1-5% further than the linear length of the cable, making copper cables of the same length potentially faster (though in a 100m cable, it’s only a difference of maybe a few nanoseconds).


Anything that converts light to electricity or electricity to light is going to induce a signal delay. Whether or not it affects your experience depends on how that conversion is happening. Using the electrical signal to drive an LED isn’t going to be noticeable. Consuming a data packet from the copper and retransmitting it as light (possibly re-encoded for better performance in the different medium), could induce a noticeable delay.

Can you provide examples via HDMI fiber signal adding latency? I provided negligible latency difference and told it was fake...
 

BinarySynapse

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Can you provide examples via HDMI fiber signal adding latency? I provided negligible latency difference and told it was fake...

I don’t have any specific examples, but anything less than 100m will never have any measurable lag. Making a cable that has enough signal processing to induce a noticeable lag would be uneconomical and have zero benefit. Then again... you have people willingly paying $100 for 2m triple shielded, water isolated, internal grounded audio cables to make sure they never hear that 0.000000001% signal distortion.
 

vick1000

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LOL so you have nothing...though so. I provided info and the first reply is FAKE! If I found it using Google but you can't yeah that tells me a lot. Go be a forum expert somewhere else.
What the hell are you talkng about. I told you I have found nothing. You are the one claiming to have sources and not posting them because you cannot be bothered. Don't try accusing me of what you are doing. I don't use Google, I use Duck Duck Go. If you can't provide a f*cking link to your source, you are a dipsh*t or don't have one, or BOTH.
 

Bowman15

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What the hell are you talkng about. I told you I have found nothing. You are the one claiming to have sources and not posting them because you cannot be bothered. Don't try accusing me of what you are doing. I don't use Google, I use Duck Duck Go. If you can't provide a f*cking link to your source, you are a dipsh*t or don't have one, or BOTH.

Found it...https://www.retrorgb.com/fiber-optic-hdmi-cable-lag-tested.html

Now piss off...
 
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Bowman15

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I don’t have any specific examples, but anything less than 100m will never have any measurable lag. Making a cable that has enough signal processing to induce a noticeable lag would be uneconomical and have zero benefit. Then again... you have people willingly paying $100 for 2m triple shielded, water isolated, internal grounded audio cables to make sure they never hear that 0.000000001% signal distortion.

Thanks, I will bow to your expertise...I wanted to find some info either way regarding lag. Not much out there. 😬
 

vick1000

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There, that wasn't so hard, was it? Now that I have the source, and have partaken, it's that writer's opinion that some fiber cables and repeaters can add lag. The specific model he tested does not. So we are stuck having to find results, or test for ourselves on a product by product basis, until a standard is develpoed, if ever. As I said at the begining, it's cheaper to try the repeater/ booster option for experimentation.
 

hajalie24

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This thread just shows the ridiculousness of people on the internet, willing to argue so much about something that barely matters. Let's try to help OP out and not argue over semantics.

OP asked if there was "noticeable" input lag. Even with vick's comments about how converting a signal will result in some lag, this isn't going to be noticeable obviously and Bowman proved this. I guarantee you're going to run into way more issues with repeaters over long super long distances versus a fiber optic cable, especially with high bandwidth like HDMI 2.1. Also, the repeaters seem pretty expensive ($25?), I'd rather get a 50ft fiber optic cable versus the repeater + 2x 25' HDMI cables which will likely cost the same.

But then again, OP is only talking about 6m which isn't much distance. If OP only needs an HDMI 2.0 signal there are plenty of copper cables that will do the job.
 

Bowman15

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There, that wasn't so hard, was it? Now that I have the source, and have partaken, it's that writer's opinion that some fiber cables and repeaters can add lag. The specific model he tested does not. So we are stuck having to find results, or test for ourselves on a product by product basis, until a standard is develpoed, if ever. As I said at the begining, it's cheaper to try the repeater/ booster option for experimentation.
Sorry about being stubborn mybad, stressful couple of days for work, etc. Between me and you I'd stick to good copper until prices come down as well.
 
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