Access Images and Audio with AVFoundation
===

I am using AVFoundation for accessing images and audio for making video. Problem is when i am adding device for audio like.

    AVCaptureDevice *audioDevice     = [AVCaptureDevice defaultDeviceWithMediaType: AVMediaTypeAudio];
	AVCaptureDeviceInput * microphone_input = [AVCaptureDeviceInput deviceInputWithDevice:audioDevice error:nil];
	AVCaptureAudioDataOutput * audio_output = [[AVCaptureAudioDataOutput alloc] init];
	[self.captureSession2 addInput:microphone_input];
	[self.captureSession2 addOutput:audio_output];
    dispatch_queue_t queue2;
	queue2 = dispatch_queue_create("Audio", NULL);
	[audio_output setSampleBufferDelegate:self queue:queue2];
	dispatch_release(queue2);

and Camera for images.

    AVCaptureDevice *cameraDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
	
	//putting it on the input.
	AVCaptureDeviceInput *captureInput = [AVCaptureDeviceInput deviceInputWithDevice:cameraDevice error:nil];

	//selecting the Output. 
	AVCaptureVideoDataOutput *captureOutput = [[AVCaptureVideoDataOutput alloc] init];

	[self.captureSession addInput:captureInput];
	[self.captureSession addOutput:captureOutput];
    dispatch_queue_t	queue;
	queue = dispatch_queue_create("cameraQueue", 0);
	[captureOutput setSampleBufferDelegate:self queue:queue];
	dispatch_release(queue);

and after all getting raw data through delegates

    - (void)captureOutput:(AVCaptureOutput *)captureOutput 
    didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer
	   fromConnection:(AVCaptureConnection *)connection 
    { 	
    if ([captureOutput isKindOfClass:[AVCaptureAudioDataOutput class]]) 
		[self sendAudeoRaw:sampleBuffer];
	if ([captureOutput isKindOfClass:[AVCaptureVideoDataOutput class]]) 
		[self sendVideoRaw:sampleBuffer];}

**the speed of getting Images Raw data is very slow around 2 images per second. how can i improve it because i am looking around 10-12 images/second.
please Help**