Re:O.mg Cable
by crazygringo on Saturday September 04, 2021 @11:18AM
(#28415862)
I'm not sure what point you're trying to make? Basic 1080p is 3.96 Gbps. Lightning is 480 Mbps. The bandwidth isn't there according to how lightning was designed.
Re:O.mg Cable
by Dylan16807 on Saturday September 04, 2021 @01:54PM
(#28417375)
> Basic 1080p is 3.96 Gbps.
Yes. (Well technically you need 3.20 or 3.33 for 1080p60, and HDMI 1.0 supports 3.96)
> Lightning is 480 Mbps. The bandwidth isn't there according to how lightning was designed.
Not true. Lightning has two differential data pairs. The port can do much more than 480 Mbps.
If your response to that is "oh, but it's only connected to pins that do 480", they would have to reconnect it to video pins anyway to do HDMI out. And nothing else in the lightning ecosystem would limit it, because this is a directly-attached adapter.
Also some of the iPad Pros have actual usb 3 support on their lightning ports.
And I'll even leave aside the issue of running a whole OS just to decode video.
But this is dealing with 1080p output. That's not very intensive. A lightning port has two high speed data pairs. You don't even need USB 3 speeds to transmit HDMI over one of those data pairs, and then put in like a $2 redriver.
If you set up double-sided output I think you could even have a passive lightning to HDMI adapter. But that's a side issue, my main point is the bandwidth available that makes these tradeoffs unnecessary.