I would like to know the follwing information about iPhone audio system
Heirarchy of the audio framework in iPhone OS.
i know that there are 3 main audio frameworks in iPhone OS.i.e
AVFoundation Framework
CoreAudio Framework
OpenAL Framework
what are the audio formats supported in each of the above framework?I mean will all the framework support all audio formats or are they dependent about the audio formats it support?
Thank You
For AVFoundation,CoreAudio pls check this link -- LINK
And for OpenAL this link might help you -- Link
Related
Is it possible to play MIDI files on iOS?
This would be the MIDI format file I was trying to play back.
Which framework / library could be used to play MIDI files on iOS?
Short answer : use the CoreMIDI framework to read the file, and the Core Audio framework to make sound (you'll also need to add the AudioToolbox framework).
Here's a tutorial on the subject
Basically, you can use the MusicPlayer object found in the AudioToolbox framework to read your file, then use the MusicPlayer to play notes on an AUSampler Audio Unit.
Is it possible to record video on iphone 3g with ios 4.1 using AVFoundation?
I m able to record audio and can pick still image using AVFoundation but not able to record video.
If you see the AVFoundation reference documentation its stated that
You should typically use the
highest-level abstraction available
that allows you to perform the tasks
you want. For example:
If you simply want to play movies, you can use the Media Player
Framework (MPMoviePlayerController or
MPMoviePlayerViewController), or for
web-based media you could use a
UIWebView object.
To record video when you need only minimal control over format, use the
UIKit framework
(UIImagePickerController).
As long as a device has a camera, you should be able to record using AVFoundation, check out the AVCam demo code from WWDC 2010 to see how you can do that.
I am working on creating a DJ mix app for Iphone in which a user can select two audio files and can select parts of the audio files to create a new audio files.
I was going through some libraries for audio mixing, I was going though Extended Audio Services libraries in Iphone SDK, since its a new field for me..(as it is an academic project) can anyone tell..me how to start with my application, like which libraries can be helpful and..how the application should work like...whether a user should first mark the audio file listen to it and then stop it at checkpoint and add the audio file to the new audio files ..This is what I was thinking of doing it...is my approach right??..
I would be very much thankful to your guidance.
There is a WWDC video called Audio Development for iPhone OS available if you are a registered apple developer on developer.apple.com.
Some of the frameworks used for this sort of thing are AudioToolbox AudioUnit and AVFoundation. AudioUnit is shown in this video as being specifically for mixing. I am no expert but hopefully this gets you headed in the right direction!
I know that AVFoundation framework works on iPhone.
Does the same framework be used for Mac as well to play and record sounds???
Basically I want to write an application to play 2 music files parallelly and record the music that is being played. Is it possible???
No, AVFoundation is for the iPhone only.
What does work cross platform (iPhone, OS X) is the Audio Queue framework. It is more difficult to use but there are plenty of examples available. It is also more low level so it will allow you to do stuff like playing and recording.
In the documentation I see several Apple frameworks for audio. All of them seem to be targeted at playing and recording audio. So I wonder what the big differences are between these?
Audio Toolbox
Audio Unit
AV Foundation
Core Audio
Did I miss a guide that gives a good overview of all these?
I made a brief graphical overview of Core Audio and its (containing) frameworks:
The framework closest to the hardware is Audio Unit. Based on that there is OpenAL and AudioToolbox with AudioQueue. On top, you can find the Media Player and AVFoundation (Audio & Video) frameworks.
Now it depends on what you want to do: just a small recording, use AVFoundation, which is the easiest one to use. (Media Player has no options for recording, it is - as the name says - just a media player.)
Do you want to do serious real-time signal processing? Use Audio Unit. But believe me, this is the hardest way. :-)
With iOS 8.0 Apple introduced AVAudioEngine, an Objective-C/Swift based audio graph system in AV Foundation. This encapsulates some dirty C-stuff from Audio Units. Due to the complexity of Audio Unit it is maybe worth a look.
Further readings in the Apple Documentation:
Core Audio Overview: Introduction
Multimedia Programming Guide
Audio & Video Starting Point
Core Audio is the lowest-level of all the frameworks and also the oldest.
Audio Toolbox is just above Core Audio and provides many different APIs that make it easier to deal with sound but still gives you a lot of control. There's ExtAudioFile, AudioConverter, and several other useful APIs.
Audio Unit is a framework for working with audio processing chains for both sampled audio data and MIDI. It's where the mixer and the various filters and effects such as reverb live.
AV Foundation is a new and fairly high-level API for recording and playing audio on the iPhone OS. All of them are available on both OS X and iOS, though AV Foundation requires OS X 10.8+.
Core Audio is not actually a framework, but an infrastructure that contains many different frameworks. Any audio that comes out of you iOS speaker is, in fact, managed by Core Audio.
The lowest-level in Core Audio that you can get is by using Audio Units, which you can work with by using the AudioToolbox and the AudioUnit frameworks.
The AudioToolbox framework also provides a bit higher level abstractions to deal with playing/recording of audio using AudioQueues, or managing various audio formats by using various Converter and File Services.
Finally, AV Foundation provides high level access to playing one specific file, and MediaPlayer gives you access (and playback) to your iPod library.
This site has a short and excellent overview of core features the different API's:
http://cocoawithlove.com/2011/03/history-of-ios-media-apis-iphone-os-20.html
Here you can find an overview of all iOS and OSX audio frameworks:
https://developer.apple.com/library/ios/documentation/MusicAudio/Conceptual/CoreAudioOverview/WhatsinCoreAudio/WhatsinCoreAudio.html#//apple_ref/doc/uid/TP40003577-CH4-SW4