[SOLVED] maximum length of HDMI for HTPC

[Danknank]

currently i'm trying to setup my HT (downstairs living room), i'm trying this without needing another computer in the living room and just use my gaming pc in my room (upstairs) because i want a better horsepower to game.
I was wondering what is the maximum length of an HDMI cable before it starts showing lags, and if the length between my room and my living room was around 35 m ± how do i resolve this issue? (because I've read some forums claiming the maximum length is around 25 m ± but i'm still unsure)
thanks in advance 🙏

 

[Glenwing]

currently i'm trying to setup my HT (downstairs living room), i'm trying this without needing another computer in the living room and just use my gaming pc in my room (upstairs) because i want a better horsepower to game.
I was wondering what is the maximum length of an HDMI cable before it starts showing lags, and if the length between my room and my living room was around 35 m ± how do i resolve this issue? (because I've read some forums claiming the maximum length is around 25 m ± but i'm still unsure)
thanks in advance 🙏

There is no specific maximum length. If you want an HDMI cable that will work, you just need one with the proper certification. For 1080p 144 Hz or 1440p 60 Hz, a High Speed certified HDMI cable will be fine, for 4K you would want a Premium High Speed certified HDMI cable.

 

[sizzling]

My experience and observation is you can have problems when you get to 10m and above. I’ve not used them but for the distances you are looking at I believe you would want to do HDMI over Ethernet using something like this https://www.amazon.co.uk/Extender-N...argid=aud-860528267405:pla-573591964921&psc=1

 

[Solandri]

The problem isn't lag. Signals travel over a cable at the speed of light (actually a bit slower but that's another discussion). So 35 meters only introduces 0.0001 ms of lag. Any noticeable lag is introduced at the interfaces and (for wireless) compression/decompression and encryption/decryption of the signal.

The problem is the voltage of the signal drops the further it travels. Eventually it drops so much that the receiving end can't understand the signal anymore, and the cable "doesn't work." The amount of voltage drop also depends on wire thickness. The thinner the wires, the more quickly the voltage drops. So your standard thickness HDMI cables are only good up to about 5 meters.

There are several solutions people have come up with to make longer cables:

• Make the wires thicker. This works to a certain extent, but it comes at the cost of making the cable thicker and bulkier. I've seen this done for cables up to about 15 m, but the cable ends up being almost as thick as a garden hose.
• "Active" cables. You boost the signal at the signal source, so it can travel further along the wires before the voltage drops to unusable. I've seen these cables go up to about 25 m (I own a 20 m one, which is only slightly thicker than a standard HDMI cable). The downside is the cables aren't reversible - the boosting end has to be plugged into the source. Monoprice sells these as "Redmere" cables.
• Optical cables. These convert the HDMI signal into optical signals. The cable itself is fiber optic. At the display end the signal is converted back into HDMI. I've seen these up to 30 m. The problem is they're much more expensive.
• HDMI over ethernet. Exactly what the name sounds like. The HDMI/ethernet converters are expensive, but you can just use plain ethernet cables to get up to 100m (or more), so the price is more or less independent of the length.
• HDMI over wireless. I don't have any experience with these. But just based on the signal bandwidth alone (HDMI is 10-18 Gbps) I'd be skeptical about it working that well.

Another solution which may provide acceptable performance is a streaming setup. All modern GPUs come with h.264 encoders and decoders built into them which can handle 1080p video in real-time. Your gaming PC converts the game video into a 1080p stream, and a receiving computer connectedto your TV converts the stream back into video. Some rudimentary code transmits keyboard and mouse input back to your gaming PC. This method does introduce some lag, plus image degradation (it has to be compressed).

Steam Link was one such device, but they don't sell them anymore. The software is still available though, and I hear there's a version for Raspberry Pi. Parsec is another app for Raspberry Pi which will do the same thing, though I have no experience with it. Nvidia added what looked like a feature which could do the same thing to their drivers a year or two ago, but I haven't explored it.

 

[Danknank]

The problem isn't lag. Signals travel over a cable at the speed of light (actually a bit slower but that's another discussion). So 35 meters only introduces 0.0001 ms of lag. Any noticeable lag is introduced at the interfaces and (for wireless) compression/decompression and encryption/decryption of the signal.

The problem is the voltage of the signal drops the further it travels. Eventually it drops so much that the receiving end can't understand the signal anymore, and the cable "doesn't work." The amount of voltage drop also depends on wire thickness. The thinner the wires, the more quickly the voltage drops. So your standard thickness HDMI cables are only good up to about 5 meters.

There are several solutions people have come up with to make longer cables:

• Make the wires thicker. This works to a certain extent, but it comes at the cost of making the cable thicker and bulkier. I've seen this done for cables up to about 15 m, but the cable ends up being almost as thick as a garden hose.
• "Active" cables. You boost the signal at the signal source, so it can travel further along the wires before the voltage drops to unusable. I've seen these cables go up to about 25 m (I own a 20 m one, which is only slightly thicker than a standard HDMI cable). The downside is the cables aren't reversible - the boosting end has to be plugged into the source. Monoprice sells these as "Redmere" cables.
• Optical cables. These convert the HDMI signal into optical signals. The cable itself is fiber optic. At the display end the signal is converted back into HDMI. I've seen these up to 30 m. The problem is they're much more expensive.
• HDMI over ethernet. Exactly what the name sounds like. The HDMI/ethernet converters are expensive, but you can just use plain ethernet cables to get up to 100m (or more), so the price is more or less independent of the length.
• HDMI over wireless. I don't have any experience with these. But just based on the signal bandwidth alone (HDMI is 10-18 Gbps) I'd be skeptical about it working that well.

Another solution which may provide acceptable performance is a streaming setup. All modern GPUs come with h.264 encoders and decoders built into them which can handle 1080p video in real-time. Your gaming PC converts the game video into a 1080p stream, and a receiving computer connectedto your TV converts the stream back into video. Some rudimentary code transmits keyboard and mouse input back to your gaming PC. This method does introduce some lag, plus image degradation (it has to be compressed).

Steam Link was one such device, but they don't sell them anymore. The software is still available though, and I hear there's a version for Raspberry Pi. Parsec is another app for Raspberry Pi which will do the same thing, though I have no experience with it. Nvidia added what looked like a feature which could do the same thing to their drivers a year or two ago, but I haven't explored it.

Thanks for the answer, i have a better clarity around the situation. I'm currently eyeing at the steam link solution and the HDMI/ethernet converters as you've suggest because i think they are the reasonably priced solutions.