Apple's Lightning-to-HDMI Dongle Secretly Packed With ARM, Airplay 392
New submitter joelville writes "After noticing artifacts and a 1600 × 900 image in the output from Apple's new Lightning Digital AV Adapter, the Panic Blog sawed it open and found an ARM chip inside. They suspect that video bypasses the cable entirely and instead uses Airplay to stream three inches to make up for the Lightning connector's shortcomings."
Disappointing for a new connector (Score:3, Informative)
With its limited pin count, it's not a surprise that the Lightning connector does not have the bandwidth to transfer uncompressed video. But it's disappointing for it to be so bad at compression, with the MPEG artifacts shown in the article, plus latency issues with encoding/decoding. On that point, the old connector was better, and micro-USB3 would have had enough bandwidth to avoid the issue completely.
Re:Wireless wire? (Score:5, Informative)
Rather they charge more for less capabilities: The old device supported real, uncompressed video. The new adapter has MPEG artifacts and added latency.
Re:Good engineering? (Score:4, Informative)
Remember when Apple was known (at least by the general public) as being the company with simple, elegant engineering?
How the mighty have fallen. Really, needing a computerized cable is just silly.
The problem is likely that Lightening likely doesn't have enough pins to just pass through HDMI like the old connector.
Silly? Maybe, but all of Apple's competitors are doing something similar because micro USB also lacks sufficient pins to pass through HDMI. (http://en.wikipedia.org/wiki/Mobile_High-Definition_Link) Except they're shoveling half the chips into the device, which increases costs on that side.
Re:Wireless wire? (Score:3, Informative)
Re:Wireless wire? (Score:5, Informative)
After they made such a big deal of the new dock connector, turns out is is inferior to their competitors. Samsung's modified micro USB connector does uncompressed full 1080p HDMI. The cables are dirt cheap too.
Do you even know what "serial" means? (Score:5, Informative)
With its limited pin count, it's not a surprise that the Lightning connector does not have the bandwidth to transfer uncompressed video.
Good grief. How many pins, exactly, would you say are needed for a serial connection?
Now look at the end of any USB cable and the end of a Lightning connector. What is the pin count between the two?
micro-USB3 would have had enough bandwidth
Also look at how many pins are in a USB 3 connector (HINT: ITS THE SAME).
This issue has nothing to do with bandwidth from Lightning.
Of course it has a CPU in it. (Score:5, Informative)
Of course it has a CPU in it. Something has to do the protocol conversion.
It's not clear that Apple's AirPlay protocol [github.com], which has HTTP connections in both directions, is involved. But the pictures indicate compression artifacts. The original article doesn't go into enough detail to determine whether image compression (like JPEG) or motion compression (like MPEG) is being used. An MPEG compressor would introduce visible lag between the master and slave screens.
Re:Good engineering? (Score:1, Informative)
their god is dead
Re:Airplane mode? (Score:4, Informative)
Bizarrely, MHL (which also has 8 or 11 pins depending on whether your device comes from Samsung; the connector is not part of the standard) can do 1080p HDMI while having much cheaper (and probably much simpler) cables to boot. It appears that either Lightning is noticeably inferior to MHL or Apple just managed to badly screw up the adapter.
Re:Do you even know what "serial" means? (Score:5, Informative)
"Good grief. How many pins, exactly, would you say are needed for a serial connection?"
One, if you're operating an old telegraph. Eleven, if you're doing HDMI. Four twisted pairs for differential serial, plus three that are used for control information. Monitor resolution detection, that sort of thing.
http://www.hdmi.org/installers/insidehdmicable.aspx [hdmi.org]
Some devices appear to do it with less, but they are actually using MHL, not HDMI.
Re:Of course it has a CPU in it. (Score:3, Informative)
Although I don't have the means or desire to test it, it is far more likely that they decided most of what people would want to output via HDMI was H.264-encoded video. So they made an interface where H.264 was streamed over the lightning connector, and converted by this adapter to HDMI. Probably both sides use HDCP or similar protections.
The limitations Panic encountered are because the video support in the iPad mini can only h.264 encode the screen (for 'mirroring') at lower-than-1080p resolutions.
Re:Stop the presses! (Score:5, Informative)
Wow, not only did you not read the article, you didn't even look at the pictures, did you?
Stop the presses! The are scaling 1024x768 content to 1600x900,
The cable is advertised as doing "up to 1080". It does not.
and there are MPEG artifacts happening as a result?!?! The deuce you say! There's never artifacts when you scale things! Never, I say!
Did you look at the picture? Those are not scaling artifacts: there is noise around edges. Those look like artifacts from MPEG or a similar compression algorithm. If it was just scaling, it would introduce aliasing patterns, which is not what they are talking about.
Next thing I know, you'll be claiming that Apple didn't replace all the already transcoded content on the Inktomi CDN with new, higher resolution content over night!
What does that have to do with this discussion?
It's almost already too scandalous that they used a CPU and software to avoid having to design and spin silicon for a Lightning-to-HDMI converter ASIC.
In fact, it looks like they did create an ARM-based ASIC, which on the face of it is bizarre to find in something sold as "an adapter cable". It's obviously doing something much more than or quite different from your standard adapter cable.
I can only echo some of the sentiments expressed in the bad ratings they received in several reviews from owners of Samsung Televisions which improperly negotiate EDID information by failing to negotiate on input sources which are not selected at the time the device comes online. One would almost think this might be an issue for Linux systems when trying to use HDMI to output to Samsung equipment, or that Dish Network DVRs might have similar problems (with the fix being to plug the device into the input channel which is selected by default when the television is powered on).
EDID? Linux? What? The article doesn't mention those topics at all. It's talking about an ARM-based chip that was unexpectedly found in a new model of a supposed "adapter cable" from Apple that is providing results that are substantially inferior to what was available on older models of Apple's similar products. As a result, if you use this cable to attach your iWhatever to a TV, you get laggy, downsampled, artifact-laden video, where Apples previous products and products from their competitors deliver sharp, un-transcoded 1080p video.
Re:Wireless wire? (Score:2, Informative)
3. Pins are dynamically assigned, so future peripherals and devices can keep physical connector and use new protocols and capabilities (real analog, etc).
4. Beveled edges and blade shape guide connector in; much easier to insert than Micro USB even when you have Micro USB right side up.
5. Cooler name.
Re:Where do you see "serial" in "Lightning"? (Score:2, Informative)
The serial/parallel distinction is completely useless in here.
The point of that is that he's claiming it can't possibly have much bandwidth without a lot of pins. So, seemingly, he's never heard of serial style connectors which never have a ton of pins compared to parallel style connectors...
And until now, all we've seen is quite underwhelming, with USB2 data cables, and now this adapter.
Neither needs to be faster. Most people now use cables only for charging. Data and even movie purchases go onto the devices wirelessly for most users. Backup happens wirelessly. Broadcasting video happens wirelessly. So Apple made cables that do on thing really well - charge rapidly - and the other tasks provide sufficient levels of performance, with some things like HDMI signals directly from the device dropped as legacy. It's pointless to support USB 3.0 speeds on data transfer when it would add to the cost of the device and yet very few users would benefit from it.
Re:Do you even know what "serial" means? (Score:4, Informative)
Nope. He is correct. Just one.
And a grounded wire at each end; sure. But there is no need to run that along the signal line. ;-)
- Jesper
There is no Airplay involved. (Score:5, Informative)
Airplay is not involved in the operation of this adapter.
It is true that the kernel the adapter SoC boots is based off of XNU, but that's where the similarities between iOS and the adapter firmware end. The firmware environment doesn't even run launchd. There's no shell in the image, there's no utilities (analogous to what we used to call the "BSD Subsystem" in Mac OS X). It boots straight into a daemon designed to accept incoming data from the host device, decode that data stream, and output it through the A/V connectors. There's a set of kernel modules that handle the low level data transfer and HDMI output, but that's about it. I wish I could offer more details then this but I'm posting as AC for a damned good reason.
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. If you wanted to produce a Lightning adapter that offered something like a GPIB port (don't laugh, I know some guys doing exactly this) on the other end, then the only support you need to implement on the iDevice is in software- not hardware. The GPIB adapter contains all the relevant Lightning -> GPIB circuitry.
It's vastly the same thing with the HDMI adapter. Lightning doesn't have anything to do with HDMI at all. Again, it's just a high speed serial interface. Airplay uses a bunch of hardware h264 encoding technology that we've already got access to, so what happens here is that we use the same hardware to encode an output stream on the fly and fire it down the Lightning cable straight into the ARM SoC the guys at Panic discovered. Airplay itself (the network protocol) is NOT involved in this process. The encoded data is transferred as packetized data across the Lightning bus, where it is decoded by the ARM SoC and pushed out over HDMI.
This system essentially allows us to output to any device on the planet, irregardless of the endpoint bus (HDMI, DisplayPort, and any future inventions) by simply producing the relevant adapter that plugs into the Lightning port. Since the iOS device doesn't care about the hardware hanging off the other end, you don't need a new iPad or iPhone when a new A/V connector hits the market.
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.
Re:Wireless wire? (Score:4, Informative)
The first is the only reason for lightning. Consumer demand and Apple policy are towards thinner and thinner products, with Apple leading the charge: They introduced lightning for the same reason the Macbook Pro lost ethernet. The connector became the limitation on thinnness, so it had to go.
If the connector became the limitation then Apple's engineers have failed. There's several phones that are thinner than the iPhone 5 on the market not only currently but also dating back to 2011 (Motorola RAZOR Droid which was a shit phone for other reasons), all of them had microUSB connectors.
The real reason is that Apple wouldn't be caught dead using an open common connector type that doesn't give them absolute control over aftermarket accessories. This is much like the bullshit of the nano SIM card that Apple claims was too big and thus limiting device size despite many smaller phones using larger SIMs. Again the reason is that Apple insisted on an edge connected SIM card where the rest of the industry had it mounted next to the battery behind the removable cover.
Re:Car analogy (Score:5, Informative)
I can do that without even needing more than one make.
GTI ($26k model), Beetle Turbo or diesel version ($24.5k), Sportwagen diesel station wagon ($27k), Jetta sedan diesel or hybrid ($24k), CC ($32k), Eos $34.7k).
So that's six cars with an automated manual under $35k, and I didn't even have to leave Volkswagen.
Re:There is no Airplay involved. (Score:5, Informative)
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.
The HD-SDI [wikipedia.org] standard can transmit a full, uncompressed HD signal over a serial connection. Why wasn't that used?
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.
Any level of compression artifacts introduced at this level is unacceptable. We understand that HD video has to be compressed to fit into a sane amount of space, but up until now all cable formats have been lossless – this is a regression.
And why does your marketing literature say 1080p output when that is clearly not true?
Re:Car analogy (Score:4, Informative)
The only "motorsport" I can think of which favors automatic transmissions is drag racing, and those are specially built units. Slushboxes are no good for really any other type of racing.