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Apple's Lightning-to-HDMI Dongle Secretly Packed With ARM, Airplay
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."
Rather they charge more for less capabilities: The old device supported real, uncompressed video. The new adapter has MPEG artifacts and added latency.
Kid-proof tablet..
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.
const int one = 65536; (Silvermoon, Texture.cs)
SJW, n: "Someone I don't like, and by the way I'm a fuckwit" - AC
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.
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.