One reason for Apple’s overpriced cables: The Lightning digital AV adapter has its own ARM SoC

Autore: ExtremeTech

Inside Apple's Lightning AV adapter: An ARM SoC!

Sending video from your phone or tablet to your TV is very useful, and many options exist for doing so wirelessly — though most existing solutions are highly compressed and quite laggy. Obviously, a wired connection is what’s needed, right? If you want a crisp 1080p signal from your iPhone or iPad, the best bet is to plug it in directly using Apple’s own $ 49 Lightning digital AV adapter. Unfortunately, it seems that this latest iteration of the device — designed to work with the new Lightning connector — isn’t putting out full 1080p. Even worse, it seems that it is introducing noticeable compression artifacts (pictured below). Now comes the search for truth amongst all of the internet rage this is kicking up among Apple enthusiasts.

Cabel Sasser, a well known software developer at Panic Inc., brought this issue to light just a few days ago. Through his own testing, he discovered that using the old Dock Connector AV adapter will output a full 1920×1080 video mirroring signal, but the newer Lightning AV adapter tops out at 1600×900. After taking a hacksaw to the tiny adapter, its apparent that this isn’t just a simple cable. In fact, it has a minuscule ARM SoC and it’s sporting upwards of 256MB of RAM. Cabel theorizes that it is using the same compression used in AirPlay to stream out the video, and that would explain the lag and artifacting being introduced to the signal. But why bother with this middle man at all? Well, we don’t have an official answer from Apple, but we have the next best thing: Wild conjecture and anonymous comments.

Compression artifacts from Apple's Lightning AV adapter

The internet exploded with countless rage-posts about how Apple is screwing consumers. As cathartic as that may be, that didn’t provide much insight. Luckily, a comment on the original post provides interesting background to the ordeal. The anonymous commenter gives plenty of detail, and hints heavily that he or she is an Apple engineer. The commenter confirms that the SoC boots into Apple’s XNU kernel, but that’s as close as it gets to being iOS-like. Lightning isn’t capable of outputting an HDMI signal, so instead of adding complexity to each device, HDMI functionality was moved into the adapter.

Under this explanation, the iPhone uses the same hardware H.264 encoding that it would use to send video wirelessly over AirPlay. It then sends that compressed data out of the Lightning serial bus, and directly to the adapter. The SoC decodes the video, and handles the rest of the trip out to the end of the HDMI plug. This accounts for all of the problems that Cabel ran into, and it seemingly has an understandable reason for existing in the first place. By having the iPhone spit out a vanilla H.264 signal out of the Lightning connector, countless adapters can be made to work with existing phones instead of relying on the phone itself to support different specs (like HDMI itself). All of the heavy lifting is done with the adapter.

The quality is a problem, but updates are certainly a possibility if this commenter is to be believed. He or she even goes as far as to claim that iOS updates on the phone or tablet will be able to improve the quality of the output. At least it won’t require you to shell out for a whole new phone or $ 49 adapter. This isn’t a good excuse for the low quality output, but at least improvement seems inevitable and free of additional cost. Now we just have to wait for Apple to get around to making this better.

Now read: Google can make Android’s streaming experience better than Apple’s AirPlay

[Image credit: William Hook & Panic]

5 thoughts on “One reason for Apple’s overpriced cables: The Lightning digital AV adapter has its own ARM SoC

  1. ciao a tutti sono un minorenne entrato a far parte del lavoro ed ho una busta paga di 800€ al mese,
    vorrei acquistare un Macbook pro e pagare con un piccolo finanziamento che la stessa Apple offre.
    vorrei sapere se io da minore però con busta paga posso ottenere tale finanziamento.
    grazie in anticipo delle risposte!

  2. Ho acquistato sul sito Apple un iMac del valore di 1400 euro e ho chiesto che mi fosse recapitato presso un TNT point nella mia città. A 20 giorni dall’ordine il TNT point dichiara di non aver ricevuto nulla e Apple dichiara di aver consegnato a loro regolarmente e di avere ricevuta di consegna firmata da chissà chi… Ho inviato ad Apple la dichiarazione firmata e in carta intestata del TNT point che attesta di non aver ricevuto nulla da ma ad Apple non basta ancora per provvedere alla sostituzione del iMac. Cosa mi consigliate di fare? Possibile che fare acquisti online sia ancora così rischioso per il cliente? (non per Apple che ha già preso i miei soldi dalla mia carta di credito…) Chi devo denunciare? Apple o il TNT point? Grazie.

  3. Ho un iphone 4s e mi ê cascato e quando lo ho sbloccato mi sono accorto che lo schermo era meno lunimoso! Non si tratta da cambiare la luminosita dalle impostazioni ma è prorio sciupato lo schermo..cmq tra poco vado all apple store e vorrei sapere come faccio a farmelo ridare nuovo, sapendo che la garanzia non copre danni accidentali.. I

  4. ciao a tutti…qualcuno di voi sà dirmi dove posso trovare un centro assistenza apple a roma ?? io abito in zona boccea e non so dove andare…….
    problema ipod ( se qualcuno mi dà un consiglio senza andare in assistenza ): è da ieri sera che, quando lo attaccato alla spina della corrente per ricaricarlo, non si carica. Ho provato anche ad attaccarlo al pc ma niente….DRAMMA!!
    10 punti assicurati…GRAZIE DI CUORE!!

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