Writing apps for iPhone - discussion

[mosc]

I'm interested in writing an app for the iphone/ipod touch. I want to write an audio processor application that will process the internal audio stream from whatever is playing - ipod, web radio, synth apps, etc.

I'm concerned that such a thing isn't really possible because of the discussion on this app: equalizer http://www.carmot.co.cc/Carmot/Equalizer.html = check out the user comments on the appstore - they are bummed.

[BobTheDog]

Hi Howard,

As a guess I would say this is very probably true, I know you have access to playlists and basic control but getting the audio stream I think is not possible.

Much of the OS is like this, It is a very closed system.

I will try to check today for you

Cheers

Andy

[BobTheDog]

I have had a look in the SDK and nothing jumps out but then again there is shitloads of stuff there.

I have posted on the Apple Dev forums so someone with more understanding than me on this may well answer.

[Inventor]

Dang, that bytes!

[BobTheDog]

[Muied Lumens]

The native player can run at the same time as some other apps, but that's about it as I understand it.

There are some pure effects apps, like reverb and EQ but I don't have them. I would think that they work by using some kind of copy/paste of audio.

Multitasking is coming in an upcoming OS upgrade (OS 4), and will probably make it onto the ipad.

That about sums up what I know about this.

[v-un-v]

From the library? No, I don't think you can. I think it's something to do with Apple's reluctance to let developers making apps that can record phone conversations, or at least that's what I read a few years back. OTOH, the app can have its own library, and this is how most get around this obstacle (although of course, it just creates another one! )

[v-un-v]

[mosc]

Thanks for the information, guys. I'll probably bump this after the new OS appears.

[Tibor]

Hi there,

I am the developer of Equalizer for iPhone and I think I can provide some help.

Apple prevents third party apps access to the iPod library. All you can do is read out a playlist and play those songs. There is no actual access to the audio samples in your iPod library.

That's why if you want to create a third party app that processes audio, you will have to get the audio into the app by other means than the iPod library. This has been solved with wifi upload.

In the mean time, audio app developers have joined forces and created a standard to exchange audio between apps (as Apple again tries to prevent apps to exchange files the easy way). The protocol to use is called AudioCopy and Paste. (there is another less popular protocol that has some merit also but is less powerfull, called Intua Pasteboard).

This means once you got your audio in one app, you can pass it on to the next app etc without need for another wifi session.

However, this does not resolve the issue at hand, accessing audio data from the iPod library. Now I am bound by NDA to comment on OS4. But just extrapolating from history, I would not hold my breath.

We (audio app devs) have posted so many requests and bug reports about this issue, that I have to believe it is not that Apple doesn't know we all want it, it's more like Apple does not *want* to provide the feature and has probably very important reasons why...

[v-un-v]

[mosc]

Tibor

Thanks for that information, no matter how sad it is.

If something happens and things with Apple open up. PLEASE post something here.

I assume that if you can't process audio from the Library, you can't process audio from a stream either. Is that correct?



In any case, Tibor, it is great to have you here. I hope you enjoy our community.