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Apple's Lightning Digital AV Adapter is a Full-Fledged Computer


macrumors bot
Original poster
Apr 12, 2001

Panic, the developers behind apps like Coda and Transmit, spent some time disassembling the Lightning Digital AV cable that allows iOS devices like the iPad mini and the iPhone 5 to output HDMI to televisions.

The company discovered that, like its Lightning to 30-pin brethren, the Digital AV adapter is considerably more complicated than it would appear. Among other discoveries, Panic found an ARM chip and 256MB of RAM inside.

There are a lot of questions. What OS does it boot? @jmreid thinks the adapter copies over a "mini iOS" (!) from the device and boots it in a few seconds every time it's connected, which would explain the fairly lengthy startup time for video out. Why do this crazy thing at all? All we can figure is that the small number of Lightning pins prevented them from doing raw HDMI period, and the elegance of the adapter trumped the need for traditional video out, so someone had to think seriously out of the box. Or maybe they want get as much functionality out of the iPad as possible to reduce cost and complexity.
Panic conjectures that for some reason the Lightning port isn't capable of outputting raw HDMI -- something that should give an extremely high quality image -- and instead uses a form of AirPlay to output video, delivering a lower quality video signal.

Update: Panic highlights this comment from an anonymous reader hinting at being an Apple engineer, which offers more details about how the adapter works and indicating that code updates are being made to improve the video quality.
The reason why this adapter exists is because Lightning is simply not capable of streaming a "raw" HDMI signal across the cable. Lightning is a serial bus. There is no clever wire multiplexing involved. Contrary to the opinions presented in this thread, we didn't do this to screw the customer. We did this to specifically shift the complexity of the "adapter" bit into the adapter itself, leaving the host hardware free of any concerns in regards to what was hanging off the other end of the Lightning cable. [...]

Certain people are aware that the quality could be better and others are working on it. For the time being, the quality was deemed to be suitably acceptable. Given the dynamic nature of the system (and the fact that the firmware is stored in RAM rather then ROM), updates **will** be made available as a part of future iOS updates. When this will happen I can't say for anonymous reasons, but these concerns haven't gone unnoticed.

Article Link: Apple's Lightning Digital AV Adapter is a Full-Fledged Computer


macrumors 65816
Nov 2, 2008
That is cool! It is amazing how much tech they managed to put inside such a small adapter. :eek:


macrumors 604
May 4, 2002
Go Vegan
Does their comment at the end mean that the video output quality is poor? That would be disappointing. Especially considering the cost of such an adapter.

macrumors 65816
Nov 10, 2006
Kind of sad that the 4th gen iPod Touch that they still sell for $199 and up only has as much RAM as an AV Adapter.


macrumors regular
Apr 1, 2009
2 quick thoughts;

The processing power is likely to be greater than the original Apple Mac computer.

The reason you normally do things in software is to either cut costs (customised ASICs are not cheap!), or to enable future changes, bug fixes or performance improvements. Are Apple simply thinking ahead to developments such as 4K, 4K 3d?


Aug 11, 2003
Listen sonny!

Back in my day the only thing our cables had in them was Lead and Copper, and that is how we liked it!!!


Oct 7, 2010
Yet more proof that lightning is a junky and expensive connector. 2013 and can't output 1080p?

This is the year of the Android.


macrumors 601
Sep 16, 2007
Northeastern Ohio
Funny how simple adapters are more complex and probably faster than computers from a decade ago :D

10 years from now, We'll probably need a 12 core 64GB Thunderbolt 4.0 cable.


macrumors 65816
May 8, 2008
Yet more proof that lightning is a junky and expensive connector. 2013 and can't output 1080p?

This is the year of the Android.
Isn't this an apple fan site?!!! Why are you here instead enjoying the company of your brethren on an android site?


macrumors regular
Jul 17, 2011
New expensive adapter, can't do 1080p and has video artifacts? ******

Older, cheaper adapter can do clear artifact-free 1080p, not ******.
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macrumors 68000
Jul 1, 2009
How long until someone manages to hack this into a fully-fledged mini-PC??

Tell me when somebody gets XBMC running on it. It already has the video output port -- just need to connect a hard drive to the lightning side.


macrumors 6502a
Apr 10, 2009
Yet more proof that lightning is a junky and expensive connector. 2013 and can't output 1080p?

This is the year of the Android.

Agreed. Lightning is a horrible adapter. It's not meant to benefit the consumer, but to shift extra cost onto the consumer. In order to make the iPhone lighter and thinner (something not demanded by the customer, but by marketing), they took out most of the onboard processing of video, audio, etc. But they didn't cut the cost of the unit.

The lightning connector could easily have been twice as wide with the same utility, the same ability to flip it, etc., and then the phone could be doing the processing, we would still have analog audio and video out, and HDMI out. But Apple wanted to cut corners and screw over customers in the process.

Lightning is just one of the negatives of the iPhone 5, but I'm stuck with mine.


macrumors 603
That's very "embedded device and OS" cool. I was configuring a brand new HP all-in-one printer to an old PowerBook OSX 10.5.x since the printer came with a spanking new iMac. The computer downloaded the driver from the printer!.

I live in a new age.

My takeaway isn't any of the ones you guys had. To me this indicates that 2-3 generations from now there will be an IC with all that stuff in about 4x4x4 mm. This is the iWatch prototype! Manufacturing testing with customer development and feedback.

Just Rocketman
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