http://eureka.ykyuen.info/2010/06/02/iphone-configuring-the-avaudiosession-and-output-audio-to-iphone-speaker/

iPhone – Configuring the AVAudioSession and Output Audio to iPhone Speaker

Posted on June 2, 2010

I am working on the AVAudioRecorder and AVAudioPlayer. By default, the output audio is routed to the receiver instead of the iPhone speaker. In order to fulfill my requirement, i have to configure the AVAudioSession in the AppDelegate.

There are 2 ways to route the audio output to speaker.

• Overriding the output audio route
• Changing the default output audio route (iPhone OS 3.1 or above)

If you only overriding the output audio route, the audio output will revert to the receiver instead of the speaker when u plugging in and then unplugging the headset. Therefore, it’d be better to change the default output audio route. but please note that it only support iPhone OS 3.1 or above.

Here comes to the codes.
1. Load the AVFoundation and AVToolbox frameworks into your Xcode project.

2. Import the header file in the AppDelegate.h

1#import <AVFoundation/AVFoundation.h>

2#import <AudioToolbox/AudioToolbox.h>

 

3. Add the following code in applicationDidFinishLaunching method in AppDelegate.m

01// Set AudioSession

02NSError *sessionError = nil;

03[[AVAudioSession sharedInstance] setDelegate:self];

04[[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayAndRecord error:&sessionError];

05 

06/* Pick any one of them */

07// 1. Overriding the output audio route

08//UInt32 audioRouteOverride = kAudioSessionOverrideAudioRoute_Speaker;

09//AudioSessionSetProperty(kAudioSessionProperty_OverrideAudioRoute, sizeof(audioRouteOverride), &audioRouteOverride);

10 

11// 2. Changing the default output audio route

12UInt32 doChangeDefaultRoute = 1;

13AudioSessionSetProperty(kAudioSessionProperty_OverrideCategoryDefaultToSpeaker,sizeof(doChangeDefaultRoute), &doChangeDefaultRoute);

 

Then u can try the playback with the AVAudioPlayer
 

Done =)

Reference: Audio Session Cookbook – Redirecting Output Audio