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The Lightning Digital AV Adapter Surprise

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Re: The Lightning Digital AV Adapter Surprise

#51

Post by moreati »

DannyBee wrote: post #36
czhiddy wrote: post #33

Earlier quoted context omitted.

The form factor of Lightning is top notch - all of the USB-variants seem terribly designed after using it. Too bad Lighting isn't free-to-license like Firewire was. That said, the design for this AV adapter is puzzling. I wonder what the hardware limitation was that prevented straight digital video out. (# of pins?)

There are definitely not enough pins to do straight pin for pin HDMI through lightning. Of course, if you are going to go to the trouble to do what they did, you may as well bitstream it through the adapter, ...

According to Wikipedia MHL allows proprietary connectors, and MHL-through-microUSB is most often done with 5 pins. Lightning is 8 pins + shield, so it would have been possible for Apple to put HDMI signalling inside the devices, and get native 1080p/60 out.

However, MHL-through-Lightning might have prevented the AV adaptor having a daisy chained lightning socket of it's own. Maybe that's why Apple jumped through these hoops.

Re: The Lightning Digital AV Adapter Surprise

#52

Post by adamisen »

adamisen wrote: post #44
seanp2k2 wrote: post #30

One must wonder why they chose to expend significant R&D to make a complicated, power-sucking adapter for use on a mobile device that provides sub-par output and costs quite a bit more than a "dumb" cable. Maybe I'm missing something, but I feel like Lightning is just the next Firewire without all the usefulness that FW had (low latency, dedicated bus that wasn't USB, lots of pro audio gear that worked with it, abili…

Hopefully it's in pursuit of a connector that's somewhat forward & backward compatible for the next decade. It would be nice to learn more about Lightning. In particular the 1600x900 limitation is irritating. It'd be reassuring if this is something that will be addressed with a firmware update (similarly with the artifacts, though I have somewhat less hope for improvements there). I'm gung-ho for Lightning but if it…

After careful parsing of Apple's specs languag, I now believe that mirroring from sub 1080P devices (iPad mini, iPhone, iPod touch) is limited to 1600x900 but that 1080P video playback works (presumably without lame encode artifacts). It appears full size iPads will mirror 1080P.

It makes sense...

Re: The Lightning Digital AV Adapter Surprise

#53

Post by adamisen »

supercoder wrote: post #4

I think they're way off on the theory the cable is running iOS. I think what's most likely is the phone is putting out a h264 stream and the chip is just decoding it. Rather than a whole ios stack & AirPlay protocol. Sure this shares some similarities with how AirPlay works (showing a h264 stream from the device ) but wouldn't require a whole system on a chip just for showing this feed.

It makes a lot of sense to me now. The adapter is tied to iOS's supported video formats. If it will play on the device, it will play on the adapter. The downside being that mirrored content has to go through the not-awesome encoder (at least on the A5). Using the same optimized software stack and shared SoC logic probably eliminates a bunch of headaches and saves money.

If it really works like that it's kind of brilliant. Future devices will have better mirroring output due to better hardware encoders (I haven't scrutinized the mirrored output from an A6, it may already be a lot better than the output pictured in the post). It ought to work with every Lightning device. The only question is future video format support, but since it's limited to 1080P it's probably future proof enough.

Re: The Lightning Digital AV Adapter Surprise

#54

Post by coldtea »

seanp2k2 wrote: post #30

One must wonder why they chose to expend significant R&D to make a complicated, power-sucking adapter for use on a mobile device that provides sub-par output and costs quite a bit more than a "dumb" cable. Maybe I'm missing something, but I feel like Lightning is just the next Firewire without all the usefulness that FW had (low latency, dedicated bus that wasn't USB, lots of pro audio gear that worked with it, abili…

>One must wonder why they chose to expend significant R&D to make a complicated, power-sucking adapter for use on a mobile device that provides sub-par output and costs quite a bit more than a "dumb" cable.

And people have answered this convincingly. From comments on TFA:

= = = = =

The reason behind this stupid expensive solution: It seems that the lightning connector is similar to the thunderbolt connector idea.

With USB you have Power/USB/MHL output. Each method requires a specific combination of pins. Updating to a different protocol, support for other devices requires difficult pin sharing (thus hardware modification), support for currently unknown future connections is impossible. If in the future something new appears it won’t work with older USB devices.

With lightning you can connect anything. Similar to thunderbolt it does not use a specific protocol to handle a specific task. It uses a general method to communicate between adapter and iOS device. That way Apple can send anything through this lightning adapter. The adapter itself gets updated automatically because it loads its firmware from the used device. So Apple can send USB2.0, USB3.0, Analog audio, Digital Audio, HDMI and any new standard through it, in theory.

The idea is great: The lightning adapter will be Apples only port and it will remain future proof.

In reality however, the lightning connector also has a limited bandwidth thus they have to compress their data, the conversion to and from the Apple lightning protocol requires lots of processing power, on both sides, and reduces quality. And finally it’s expensive.

Apple should have tried to use thunderbolt instead of their own propietary technology, but then they would have used a common technology which other manufacturers could use and benefit from, too, that’s not the way Apple likes it, so they introduced their own thing, which is crap right now.

AND:

Just remember, this is v1 hardware for a tough future proofing problem. I genuinely appreciate the lengths Apple went through to create A) a reversible plug, so you can stop mashing and flipping. B) handled all the connector options. The built in decoder module could take a compatible 1080p video stream and push that to the TV at full resolution, the screen mirroring is a separate protocol. Now I’m curious if the Lightning-SVGA adapter has the same rig!

So, v1 of the Lightning connector is probably (assuming) going at USB2 speeds. In v2 of the connector we could see USB3 (5Gbit/s) or thunderbolt (10Gbit/s) speeds, but all the accessories still work.

Assuming the faster speeds come, it’ll support 4K TV output video streams, same plug. Yay future.

Re: The Lightning Digital AV Adapter Surprise

#55

Post by AlexDanger »

raverbashing wrote: post #48
seanp2k2 wrote: post #30

One must wonder why they chose to expend significant R&D to make a complicated, power-sucking adapter for use on a mobile device that provides sub-par output and costs quite a bit more than a "dumb" cable. Maybe I'm missing something, but I feel like Lightning is just the next Firewire without all the usefulness that FW had (low latency, dedicated bus that wasn't USB, lots of pro audio gear that worked with it, abili…

My opinion: bandwidth The lightning connector doesn't have enough bandwidth to drive a HDMI connexion directly Of course, compressing (inside the iPad) for streaming, sending this through a limited bandwidth channel and then decompressing is complicated, but looks like it's the easiest solution (because all components - especially sw ones - are off the shelf) It's like a mini Raspberry-pi in that adaptor, amazing! (i…

It's like a mini Raspberry-pi in that adaptor, amazing! (if not slightly overpriced)

What a wonderful age we live in. How long ago was it that people doubted the Rasberry-Pi could be delivered at such a low price?

One of those rare moments where movement to the future is evidently palpable.

Re: The Lightning Digital AV Adapter Surprise

#56

Post by jacquesm »

micampe wrote: post #45
millerc wrote: post #29

Earlier quoted context omitted.

No need to be sarcastic. I find it interesting that somebody goes through the trouble of creating a new user account, just to confirm a theory that nobody could confirm without getting in trouble. It doesn't prove anything, but it certainly fits the context. I would say the theory (and the extra bit of information) merit being analyzed further. FWIW, a "stub copy of iOS" would mean in this context "a copy of iOS wher…

> creating a new user account that gives me less confidence, not more.

Apple has fired people over less. /. has a long standing tradition of ACs breaking rank and posting insider stuff, I see no reason why the same couldn't happen on HN.

Re: The Lightning Digital AV Adapter Surprise

#57

Post by makomk »

cabel wrote: post #11
drivebyacct2 wrote: post #7

Earlier quoted context omitted.

I honestly don't know. Someone is somehow implying that the adapter is implementing a full stack capable of being an AirPlay receiver and transcoding video on the fly. I think Cabel is wrong or has explained what they think is occuring incorrectly. /shrug

In this case, AirPlay is our easier-to-understand way of saying "the results you're getting are exactly the same as when you stream iOS video using AirPlay". (Which is really weird for a video-out dongle! Especially since the former, non-Lightning one did proper video out.) I've tweaked the post to make it clearer that AirPlay isn't _necessarily_ the _exact_ mechanism being used! It could just be H.264 or MPEG or wha…

It's not that weird at all, in a sense. With this mystery cleared up, all the evidence is basically consistent with "Lightning" being just USB 2.0 over a proprietary connector plus some proprietary authentication chips in the cables. There is literally nothing it does that could not be done with a standard micro USB 2.0 connector.

Re: The Lightning Digital AV Adapter Surprise

#58

Post by Joeri »

mjs wrote: post #49

The description on the UK Apple Store says that it "mirrors exactly what you see on your device", so that needs adjustment, at least. http://store.apple.com/uk/product/MD826ZM/A/lightning-digita...

Someone isn't practiced enough at weaselwords yet. Had they said 'mirrors in its entirety what you see on your device', they would have been accurate while misleading, while now they're just wrong.

Re: The Lightning Digital AV Adapter Surprise

#59

Post by arrrg »

signed0 wrote: post #12

So instead of just going with USB3 like other phone manufacturers and having native HDMI they created their own interface that results in an a picture display with noticeable artifacts.

The Micro USB plug is an abomination, only exceeded in horribleness by Apple’s predecessor to the Lightning plug, the Dock Connector.

Hardly anyone will use the HDMI out. Prioritizing the plug seems like the correct tradeoff to me. And make no mistake, this is what this is. It’s always about tradeoffs.

Re: The Lightning Digital AV Adapter Surprise

#60

Post by arrrg »

signed0 wrote: post #34
jws wrote: post #28

Earlier quoted context omitted.

They also have hardware in the phone to generated HDMI (although electrically modified to fit on the USB connector). Given that only a tiny percentage of people will ever plug their phone into HDMI, it makes sense to have that minority pony up $40 instead of making everyone pay an extra dollar for the hardware they will never use.

But if they cared about cutting costs they wouldn't have invented their own cable to begin with. When has Apple ever worried about making people pay for things they don't use? I'm disappointed because Lightening was billed as the next innovation in design, but if the picture quality is worse then what's the point?

Apple has no problem making pay – but they do have a problem making people pay for stuff they don’t use. Nothing to do with costs per se, it’s more a philosophical stance.
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