While trying to figure out why video output from some iDevices was so poor, the company cracked open a Lightning AV Adapter, a $US49 accessory that is sold as allowing Apple devices to send video to HDMI devices in glorious 1080p HD, and found a CPU and RAM inside.
Why does a video adapter need a CPU?
An answer, very unusually, seems to have been provided by an Apple employee who joined the burgeoning thread following Panic's blog post about its find.
The comment offers the following explanation:
“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.”"
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