I think the main takeaway is that yes, lightning is future proof and can adapt to any output you want it to.
I do wonder what's the reason for encode/decode cycle was in the first place though.
I do wonder what's the reason for encode/decode cycle was in the first place though.
And thats where all this future proof talk goes deaf. New interfaces will only have more bandwidth, thats the whole point. Meanwhile, Lightning still has the same bandwidth and theres still a considerable penalty in serializing any other interface.
If they can't even do 1080p lossless right now, they are in much deeper trouble for the future.
Let me try and shed some light on this mystery. Consider this rumor. Also, I am not an electrical engineer, so I may be talking out of my ass.
As best as I can tell, Lightning is not (yet, anyway) a real protocol like Firewire, USB, etc. What it is so far is USB with a different connector and some negotiating chips.
So when connect your lightning-USB cable to your iPhone, your iPhone squawks and says "What is this?" and the cable says "I'm USB". The iPhone then sets its pinout to USB mode and off you go.
What's so great about this, why not just use USB? I think the secret sauce is that Apple wants to surreptitiously invent new pinouts with faster data rates, without consulting any standards bodies and having to rally industry support on TVs, computers, et al. They just build some new controller to push Lightning at 2Gbps+, put it in new iPhones, and build active cables that spit out HDMI or UHDTV or USB3 or whatever it is the kids are doing these days. The active cables degrade gracefully for hardware running at the slower data rate.
What I think you are seeing right now, is the dry run with the off-the-shelf controller. Get manufacturing ramped up. You need this to plug your phone into a computer anyway. But it's just the tick. Wait for the tock.
Now the only thing that puzzles me is why they settled on 8 pins, when USB3 is 9. Obviously they wanted an even number so you could plug it in every which way, but you would think stepping up to 10 pins would let them use off-the-shelf USB3 controllers instead of USB2. Maybe they can do USB3 on 8-pins somehow, or maybe the tock will be ready fast enough that it's not worth it.
Further reading: http://brockerhoff.net/blog/2012/09/23/boom-pins/
Re pins, I'm not EE either, but I don't get why people concern about number of pins so much, as I asked earlier in this thread, is there a relation between number of pins and bandwidth (well with physics involved there is _some_)?
Traditionally it's been easier for most hardware makers to double the pin counts than to build controllers that run at twice the clock rate and also make everybody use fancy cables. But traditionally not everybody has PA Semi across the hall to build chips for you and years of experience selling $50 cables to consumers via direct retail. So I'm betting that the usual economics of the consumer data interface market don't apply to Apple.
With serial techniques such as differential encoding parallel transmission off circuit board has been obsolete for a long time. The potential skew between the pins is too great and synchronisation too complex.
Do you really think it makes more sense to decode H.264 on the device then re-encode it in another format and then decode that on the adapter ? Sounds slow, illogical and bound to introduce more artifacts.
It seems to me they had a system for outputting video via h.264, and they decided to use it again here. Seems like a reasonable decision at that point.
How so? A center pin is still the center pin when you flip it around. Odd pin counts work fine.
Is the metal prong itself the 9th pin?
Unencoded video is about the most bandwidth intensive thing I can imagine coming out of or going into a phone, and will remain so for a long time.
1080p30 @ 24bit is roughly 1.5 Gbit/sec before you talk about transport level ecoding (8b/10b) or audio.
Your splitting hairs. Pretty much all HDMI transmitter ICs have a microcontroller on board, they need a processor to deal with the protocol configuration, DDC and HDCP. Probably most are using some 8051 design plunked into the chip. They are SoCs by any reasonable definition.
The rest of this is ancillary stuff. They aren't decoding h.264 on an ARM core, that's impossible for any significant bit rate, they are doing it with a purpose built bit of hardware, just as the HDMI encoding is done in a purpose built bit of hardware. Incidentally the encoding of HDMI is a mess, the spec is worth a read some time.
Well, say right now it cannot transmit 1080p60 raw. Could it with new hardware in device and adapter? Or put another way — does number of pins limit bandwidth in any way?
Based on what has come out about lightning it appears to have 2 differential data channels (same as USB2). There will be some upper limit on frequency but its impossible to know without detailed specs. Its also not clear if one is locked as send and one as receive, or if they are configurable, there is an ancillary control channel so anything seems possible.
For comparison, HDMI has 3 data channels, each with raw bit rate of up to 3.4Gbit/sec (~2.7Gbit/sec data).
Meanwhile, lossless 1080p would require 20000% more space (no I didn't add too many zeros, that's 200 times more).
DVI, HDMI and MHL all require custom hardware in the device. As the Apple engineer said, Apple are trying to avoid this.
Avoiding custom hardware in devices just seems ridiculous - to support new standards Apple are either going to have to update their chips or update their devices, and they will have to update the cables too. There's not a saving here that isn't achieved by simply using an existing standard.
Of course dual link DVI et al can do more than 1080p. They are all huge. Apple's needs to support not just today's thin devices but those for the next decade (iWatch ?).
All we can guess is that Lightning can handle somewhere between 10Mbps (AirPlay over WiFi) and 2Gbps (native HDMI rates). We have absolutely no idea where in that range its actual capabilities lie.
It says nothing about Lightning maximum speed. Besides, whatever maximum speed can be measured with today hw, it doesn't mean that can be pushed tomorrow with different HW in the iDevice.
Besides, if we're talking about hypothetical future hardware, there's nothing to stop someone doing the same with micro-USB. (In fact, manufacturers already have in the form of MHL.)
Surely the future will be H.265 content which will have better quality for the same bandwidth. And it's unlikely that people are going to be demanding a higher output resolution than 1080p from their mobile device for anytime soon.
I could imagine people want to play 4k movies from their mobile device on their TV, but you wouldn't install a 4k screen as the display on the mobile device.
Edit: Yes, computer is inaccurate. I wanted to get the idea across that we are talking about connectors (DVI, HDMI) that you would normally use to hook up a computer or laptop to a TV or LCD. They have only recently appeared on mobile devices, but serve the same purpose here: video (and audio, for HDMI) out.
Huh? Its the plug on the bottom of a phone (and ipads now i guess). Lightning isn't on any computers.
b) Why is there a second pass compression/decompression stage ? Isn't iOS outputting the compressed H.264 stream and the adapter decoding it i.e. one stage ?
c) Given that Retina displays by definition are the best resolution we will need and it is far less than 4K it is questionable whether there will be a use for 4K on mobile devices. Other than using your iOS device as a media player for your TV (very small use case).
For the consumer who just wants to connect their device to a HDTV, it's crazy they have to pay 10x more just because they're in the Apple ecosystem and not Android.
As for being future-proof, by the time some cool new A/V interface hits the market, and we've all updated our TVs, the Lightning devices of today will be in a museum.
And economy of scale does work. I do not think Apple can seriously undercut Samsung because they managed to leave out a HDMI chip.
I think Apple's reason for this connector is more one of aesthetics: why have X > 1 chips that can communicate with the outside world and, typically, X connectors? Full wireless is not yet an option, so they need one. Then, they need some way to figure out what is on the other end of the line.
Why they didn't pick USB3, I don't know. Not proprietary enough? Connectors too bulky? Low power spec not (yet) available? Not flexible enough? Supports too many devices? (If you put an USB connector in, people will expect that it works with their hard disk, photo camera, keyboard, mouse, etc)
Why? They'll plug another $50 adapter on it and it'll work.
And that the original dock connector first appeared in the iPod 3G nearly a decade ago. So yes today's devices will be in a museum. But the connector could still be in use in 2023 and beyond. Worth keeping in mind.
Firmware loaded at runtime is not new (see many of the wifi/bluetooth dongles that don't work in linux). However, would apple let 3rd party peripherals download driver code? I wouldn't have thought they want to keep baking it into iOS itself as the number of peripherals increase. Perhaps drivers embedded in a controller app via the app store?
I like the idea that with a thunderbolt<->lightning adapter (and a huge amount of hacking) iOS peripherals are a blank canvas and could be used with other non apple devices or for purposes never originally intended (that VGA card as a software radio transmitter springs to mind...)