He doesn't say, but probably because they just don't have the bandwidth.
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.
> 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.
Yep, and the comment about them using already existent h264 support in hardware I think supports dry-run-fastest-to-deadline solution.
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_)?
Still not an EE, but as I understand it, if you are creating your own controllers and you also control how the cable is shielded, pin count doesn't matter much except for power.
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.
Has this been true since the late 80's/ early 90's when serial ports left parallel ports behind?
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.
There is pretty significant relation between number of pins and prices of almost every piece of hardware involved. IC package price is almost linearly dependent on number of it's pins and for most mass-manufactured chips packaging is major component of final price. Also wide parallel interfaces are harder to design from interference perspective and to route on PCBs. General shift to essentially serial interfaces for almost everything except main memory is motivated by simple fact that trading silicon area used by serialization/deserialization logic for less device pins, simpler boards and simpler system design is very worthwhile whenever it's at least partially possible. For very slow interfaces it has been this way for at least 30 years, since mid 90's for slow system buses (that's why around 2000 motherboards stopped having ISA slots, ISA was replaced by serial LPC interface around that time) and since early 00's for almost everything in non-specialist applications.
Why wouldn't they use H.264 and their existing hardware ?
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.
You'd need 3Gbps to push uncompressed 1080p data. If you look at USB 3.0 and make a not-unreasonable bet that Lightning is slower, then you simply don't have the bandwidth to do so.
As well as bandwidth, power consumption. Chucking 3Gbps down a long wire is going to reduce battery life for a mobile product. Perhaps the controller can support it, but heat dissipation in the phone is significant?
Actually, that doesn't make sense - the adapter is powered from the iPhone or iPad and still has to chuck 3 Gbps down a long wire, except now you're using the iPhone's h.264 encode hardware and an entire ARM SoC in the adapter which you have to power too.
Retina iPads already need to re-scale the image since they're higher resolution than an HDTV. Why force the little adapter to do (some pretty massive) scaling and encoding when the iPad has a very nice GPU?
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.
Well, there was a big whoop about the thinness of the connector when they announced it being necessary for very thin devices. Can we manufacture non-brittle connectors with center pins that are 1.5mm thick?
If you count them there are actually 16 pins. Apple wants you to think there are only 8 pins and that the connector can be reversed. But nothing prevents them from adding some additional handshaking in a future device that lets them use all 16 pins separately. The connector could still be reversible with additional switching circuitry that routes signals to the correct place depending on how you have rotated the connector.
And HDMI does it effortlessly. That's exactly what these interfaces were designed to do: raw massive data with low latency over short distances, suitable for processing in dedicated circuits, not SOCs.
> suitable for processing in dedicated circuits, not SOCs.
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.
Yes, of course. But they have the the actual transfer of the raw data offloaded onto specific circuitry that mostly just passes it through, something the processor part of a SOC would be terrible at. That's not what Apple is doing; they take in a normal lossy compressed video stream (H.264, who knows) and then reconstruct a HDMI signal.
The only difference between what you've described and what is going on in this adaptor is the inclusion of h264 decoding. The use of this is an argument that can be had (personally I think it was a great play on Apple's part, see my comment here: http://news.ycombinator.com/item?id=5308345)
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.
But then there's 4K, if we're talking about future proofing.
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?
> 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).
So, you're saying bandwidth increase while maintaining backwards compatibility won't be possible through the Lightning interface? Surely, USB 1.0 to USB 2.0 demonstrated a counter-example to your statement.
Yes, and? Lightning 2.0. Sure. That doesn't mean the physical interface changes. That doesn't mean there isn't backwards compatibility. That doesn't mean there isn't forwards compatibility. "And thats where all this future proof talk goes deaf" argument made no statements to support itself. "Meanwhile, Lightning still has the same bandwidth" is like saying "Meanwhile, USB still has the same bandwidth with USB 2.0 as it did with USB 1.0". There will be higher bandwidth Lightning 2.0 peripherals with Lightning 2.0 devices; but Lightning 1.0 peripherals will still be compatible. The Lightning interface doesn't establish some sort of permanent bandwidth cap to its future backwards-compatible revisions.
Do you mean the future where we're streaming 4k video? If HEVC (aka H.265) lives up to its promise, 4k video will come in around a mere 50% more than 1080p does now.
Meanwhile, lossless 1080p would require 20000% more space (no I didn't add too many zeros, that's 200 times more).
This isn't streaming, its the last 50cm from your computer to your display. The 200 times more of data are already handled without a sweat by today's interfaces. Dual link DVI, from 1999, can already do more than 1080p.
Apple are trying to handle all technologies without custom hardware in the device. Effectively, they have turned it into a streaming scenario. It's not as weird as you'd think -- there are USB3 video adapters that work the same way.
DVI, HDMI and MHL all require custom hardware in the device. As the Apple engineer said, Apple are trying to avoid this.
Taking 1 master protocol (DisplayPort) and converting appropriately would make a hell of a lot more sense then starting with your own proprietary format, and putting compressed video decoders in your cables.
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.
Sorry but are you talking about the right connector here ? Lightning is for the iPod, iPhone and iPad.
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 ?).
Because MHL isn't USB. It uses the same plug but runs its own HDMI hardware connection over the pins -- exactly what the Apple engineer said they were trying to avoid doing for every single hardware setup.
There's every indication that Lightning can handle much more than this but in order to get the hardware running quickly, they've reused settings that were previous used for WiFi data rates.
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.
I'm guessing its actual capabilities are basically just USB 2.0. Someone tore apart a Lightning-to-USB sync cable ages ago and the data pins are apparently wired straight through - so we know that Lightning can speak it natively - and given all the focus on simplicity and not doing multiplexing at the expense of more complexity in the adapter I can't see any reason why Apple would develop their own protocol.
That means that the CPU reconfigures the pins into USB2 mode, which means that Lightning can at least do 400Mbps. This is because any SoC nowadays can do low-level USB-device pinout, so it's reasonable to simply pass it through the lightning connector, unlike HDMI or DVI which require specific video encoders.
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.
Given there's nothing that can currently use more Lightning bandwidth than USB 2.0, and apparently 3rd-party manufacturers don't have access to anything except USB 2.0 and slow TTL serial, it'd be surprising if it did support anything else. Also quite expensive - Apple's hardware USB implementation is almost certainly third-party IP they've bought in and dropped into place unamended, modifying it to multiplex another protocol they don't need is a waste of money.
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.)
I might be really confused but why is Apple going to be in deeper trouble ?
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.
Again, this is a connector from your mobile device to a display. Nobody has ever done any lossy compression on that pathway; both because you can drive simple circuits at frequencies high enough to have plenty of bandwidth and because it would actively destroy information (hence lossy). This is such a big problem because the video you are playing has already been lossy compressed (H.265) and it will most certainly not get better by a second pass that only has the raw pixel data available.
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.
I think that if you have a 1080p source on your phone, it goes to tv as 1080 and without another compression step, it's only mirroring that reduces the resolution (which, for ipad mini, is less than 1080p btw) and introduces compression pass
a) This is a connector from a mobile device to a TV. That is the primary use case here. I doubt anybody is hooking up an iPhone to any other type of display.
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).
I think the main takeaway is, why pay for a $50 widget when a $5 cable will do the job?
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.
Somebody has to pay the piper-- the hardware to transmit HDMI has to exist somewhere. With a smart adapter, only the people who need the feature have to pay for it.
Seriously ? All the arguments about Apple products "just working" and being "premium products", now change to "only people who need the feature have to pay for it" ?
"Now"? The iMac G3 didn't have a floppy but I'm sure you could buy an external floppy drive. Macs after that rarely had a full VGA or DVI port, people had to buy adapters. Starting with the MacBook Air, we had to buy external optical drives, external ethernet adapters, external FireWire adapters... This is not news. And I'm saying that as someone who hates Lightning with all their heart :)
But given economy of scale, they (per person) will pay more for it than the amount they would have paid if everybody bought that hardware in their phone.
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)
You know you can buy Lightning cables off eBay for $5.
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.
Yes, you can get a Lightning to USB cable for charging and syncing for $5, but to connect to a TV you need to get the Lightning AV adapter which costs $50.
The interesting point to me is that a device can be future proof through iOS updates - i.e. for as long as apple is prepared to create software drivers/updates to support the peripheral. Obsolescence is now almost entirely a software rather than hardware problem. Features can be added or removed via updates.
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...)
I do wonder what's the reason for encode/decode cycle was in the first place though.