Getting started with Voip programming - real-time

I need to create a voip application ( like msn ).
What do I need in general ?

Start by learning about SIP protocol. If you don't want to do everything from scratch, you can take a look at Sofia-SIP library. Also, looking at some OpenSource Softphone projects (like Telephone) might be helpful.
Hope it helps.

Related

How to establish app to app communicaiton using socket on same device in iPhone without any server component?

I want my app to intercommunicate with my service,send and receive data to and from service
Check this:
How can I transfer files from one application to another in the same iOS device?
UIDocumentInteractionController class reference
Hope this might help to achieve your goal
There's plenty of references about that'll help you with what you're trying to achieve, I'd recommend doing a little research and attempting to get something basic working.
To get any help, you'll need to provide a bit more information - what protocol does your service operate on? what is the function of the app? what have you tried?
This place is an invaluable resource to programmers who ask for help, rather than an entire solution. :)
Good Luck!

iOS RTP library/tutorial/example

I'm wondering about the availability of a library to send and receive realtime text updates (between device and server) in a messaging-type app. I'm not really sure where to look, or what to search for, but my preliminary searches haven't had much success. Any help is much appreciated. Thanks!
How about XMPP (Extensible Messaging and Presence Protocol)? It has a very decent framework in Objective-C - http://code.google.com/p/xmppframework/.
If it's an option for you, WebSockets also come handy here. Try using zimt for instance or UnittWebSocketClient API.

Best way to implement "user to user" VoIP on iOS

I have seen some great libraries to implement VoIP on iOS but they all apply for making calls to actual numbers. All I need is communication between users of my app. Siphon seems like a great option but you have to configure it with a service which allows you to make calls. All I need is communication between my users, maybe there is a better way to do this.
Any advice is appreciated!
It's not entirely clear what you're asking, but,
all of what you describe is built in to Game Kit which is part of iOS.
You can use "Game Kit" for any sort of networking. (It does not have to be a game.) And person-to-person voice chat is completely built in. It's two or three lines of code.
Hope it helps!

Audio Fingerprinting implementation on iPhone

It's the first time I post a question in a blog, but it seems to me this is the best resource on the web for that.
I'm looking for a way to implement audio fingerprinting in an application for iPhone. I had a look at the lastfm fingerprinter, being that I already use other lstfm api calls, but porting it to the iphone seems to be a mess and I'm quiet sure that it would be highly inefficient.
Should I give the search for now as I am looking for a free service ,I'm a young private developer and don't have sufficient economic resources for a payed service. This is also the reason for which I cannot install the library on my web server and run it remotely, sending just the audio data to it. The hosting I rely on dosen't allow me to install third party applications...
Music Brainz seems to be a solution, but not quiet sure on how to obtain the fingerprint...
Any suggestions, hint, tips, links, search queries, anything?
Thanks in advance!
Christian
Check out Echoprint, an open source audio fingerprinting service provided by Echonest.
Here is the iOS example they provide on their echoprint github repo.

Getting started with libpurple

I'm writing a Cocoa Touch program that will (hopefully) use Libpurple as it's background. The only problem is that I have no clue where to get started. I've been looking through some source code of applications that do use it, but so far haven't gotten anywhere.
Does anyone know anything that will help me familiarize myself with libpurple?
First of all, you may encounter some trouble, since libpurple is licensed under GPLv2. It may be incompatible with what you are trying to do. (I am not totally sure you can have a GPLv2 app on the App Store.)
Second, you can read purple-client-example.c in the libpurple source, for a super-short example.
Also, Adium might be more useful to study than Pidgin since it is a Mac OS X app, closer to what you might do on the iPhone.
The best way to understand libpurple is to work with Pidgin, the OSS client that uses it. Study the Pidgin implementation, then start to design your own client.
If you plan to sell this, you cannot use libpurple because it is under the GNU license. Please check out my alternative AIM API for Objective-C, with a bit of tweaking, it will probably work moderately well on iPhone: LibOrange