Yes, it’s a limitation of the hardware. The iPhone uses a dedicated chip to handle decompression. The chip of course only decodes one stream at a time.

As for CoreAudio support; yes it does support the entire CoreAudio API. You can manipulate multiple audio streams, but with the limitation that only one can be from a compressed source.

The API docs state this quite clearly. I remember it because I was disappointed when I read it.

So imagine one main mixing screen that just had volume faders and an a-b fader. Perhaps there’d be one more slider to scroll the view left and right displaying virtual left and right decks… When viewing each deck, you’d only really need play, stop, and cue… and I’m sure scrolling through the actual wave form for cueing can be handled by another slider.

When it comes down to it, keep it simple… That’s one of my biggest gripes about today’s digital DJ… Half of us wouldn’t know what to do if we didn’t have a loop function or effects for transistioning. I mean I don’t wanna sound like the old man.. “Back in my day… etc etc etc…” But it is true, when it comes down to it… all you need is two turntables and a mixer, virtual or not.

Anyway, Numark has demonstrated through the iDJ device that two audio streams can be cranked out of an iPod, so I’m assuming that the iTouch and iPhone can do the same… I’m not saying that the iPhone will replace all existing devices, I’m just saying that it is possible…

1. You can only decode one compressed audio stream at a time. You could play a cached un-encoded wav parallel to the compressed stream, but the iPhone is RAM constrained making that difficult. Not forgetting that you need to decode that wav file _first_.

Are you sure about your statement? Then why during the SDK presentation Steve Jobs said that SDK had full featured CoreAudio? I guess you’re thinking about the fact the iPhone may send compressed audio to a specific chip which can proccess one compressed stream at a time, but I didn’t digg into Apple’s SDK enough to see how audio works.

@neural, such dream is quite an overkill for a device that is a PHONE.
This device would only be usefull as a xy fx controller. The creen is too small for any serious control/state overview.

I’m not expecting any serious mixing with the iPhone, a laptop will always do a better job at it, but I think that, if possible, someone could bring up a minimum of features to keep a gig going in case your laptop is dead.

For the moment, the best way if you don’t want to bring a CD player and CDs for backup solution is to bring your iPhone or iPod and one of those Numark mixers with iPod dock. It’s pretty expensive at the moment though.

We need innovation in interfaces, not lame eye-candy.

I second this.
Joke: we need nanotech to get tactile feedback from our touchscreenz.

1. You can only decode one compressed audio stream at a time. You could play a cached un-encoded wav parallel to the compressed stream, but the iPhone is RAM constrained making that difficult. Not forgetting that you need to decode that wav file _first_.

2. Only one audio out. Makes it difficult to monitor mixes. A hardware add-on could address this, but most attachments that draw audio from the dock-plug cause the headphone out to be switched off, this is a feature of the phone itself.

And just a bit of commentary; putting tiny turntables in a DJ app is a sign of shallow thinking. It couldn’t possibly emulate the real thing, it takes up more room than it needs and moreover it means nothing _interesting_ is happening. We need innovation in interfaces, not lame eye-candy.

Errrrr? soz, that just occurred to me then, and I had to say it! :)