this post was submitted on 22 Sep 2023
15 points (75.9% liked)

Ask Lemmy

27257 readers
1868 users here now

A Fediverse community for open-ended, thought provoking questions


Rules: (interactive)


1) Be nice and; have funDoxxing, trolling, sealioning, racism, and toxicity are not welcomed in AskLemmy. Remember what your mother said: if you can't say something nice, don't say anything at all. In addition, the site-wide Lemmy.world terms of service also apply here. Please familiarize yourself with them


2) All posts must end with a '?'This is sort of like Jeopardy. Please phrase all post titles in the form of a proper question ending with ?


3) No spamPlease do not flood the community with nonsense. Actual suspected spammers will be banned on site. No astroturfing.


4) NSFW is okay, within reasonJust remember to tag posts with either a content warning or a [NSFW] tag. Overtly sexual posts are not allowed, please direct them to either [email protected] or [email protected]. NSFW comments should be restricted to posts tagged [NSFW].


5) This is not a support community.
It is not a place for 'how do I?', type questions. If you have any questions regarding the site itself or would like to report a community, please direct them to Lemmy.world Support or email [email protected]. For other questions check our partnered communities list, or use the search function.


6) No US Politics.
Please don't post about current US Politics. If you need to do this, try [email protected] or [email protected]


Reminder: The terms of service apply here too.

Partnered Communities:

Tech Support

No Stupid Questions

You Should Know

Reddit

Jokes

Ask Ouija


Logo design credit goes to: tubbadu


founded 2 years ago
MODERATORS
 

I bought a cheapo capture card a while back but the quality is pretty terrible

Is there any reason PCs can't just receive HDMI/displayport input from other devices through the same mechanism they output it?

For that matter also is there any reason HDMI can't be run over Ethernet? Afaik ethernet has far more bandwitth than hdmi nowadays

you are viewing a single comment's thread
view the rest of the comments
[–] willis936 7 points 1 year ago* (last edited 1 year ago)

High speed receivers are much more complex than transmitters. Just shoving some bits down the line with a bit of emphasis filter training is not that tricky. Tuning a receiving emphasis filter while simultaneously recovering the clock and performing error correction requires many more transistors, which uses more power and costs more to produce. HDMI receiver chips on digikey are 2-10x more expensive than transmitter chips.

Beyond the technical reasons, there is the fact that media companies have a vested interest in not having video input being prolific. They have a long history of fighting technologies such as VCRs. In the shadowy internet era you can let your imagination run wild with what motivations they set up in what industries to make HDMI receivers less prolific.

Also, for those talking about HDMI over Ethernet: be careful. HDMI is actually quite high bandwidth. There's a reason the cables stop working after a few feet and it isn't because they're poorly designed or manufactured (though that's surely the case for crap you get on amazon). Cat 1 million isn't magic. It's still beholden to Shannon's limit in copper twisted pair. You can't shove 25 GbE over any copper longer than a few meters of TwinAx. There are plenty of solutions on the market that are too good to be true and simply won't work at the pixel clocks they advertise, yet will happily take hundreds of your dollars and weeks of your time.