iOS 录音功能的实现

这两天也调了一下ios的录音，原文链接：http://www.iphoneam.com/blog/index.php?title=using-the-iphone-to-record-audio-a-guide&more=1&c=1&tb=1&pb=1

这里ios的录音功能主要依靠AVFoundation.framework与CoreAudio.framework来实现

在工程内添加这两个framework

我这里给工程命名audio_text

在生成的audio_textViewController.h里的代码如下

#import <UIKit/UIKit.h>
#import <AVFoundation/AVFoundation.h>
#import <CoreAudio/CoreAudioTypes.h>

@interface audio_textViewController : UIViewController {

    IBOutlet UIButton *bthStart;
    IBOutlet UIButton *bthPlay;
    IBOutlet UITextField *freq;
    IBOutlet UITextField *value;
    IBOutlet UIActivityIndicatorView *actSpinner;
    BOOL toggle;

    //Variable setup for access in the class
    NSURL *recordedTmpFile;
    AVAudioRecorder *recorder;
    NSError *error;
}

@property (nonatomic,retain)IBOutlet UIActivityIndicatorView *actSpinner;
@property (nonatomic,retain)IBOutlet UIButton *bthStart;
@property (nonatomic,retain)IBOutlet UIButton *bthPlay;

-(IBAction)start_button_pressed;
-(IBAction)play_button_pressed;
@end

audio_textViewController.m

#import "audio_textViewController.h"

@implementation audio_textViewController


- (void)viewDidLoad {
    [super viewDidLoad];

    //Start the toggle in true mode.
    toggle = YES;
    bthPlay.hidden = YES;

    //Instanciate an instance of the AVAudioSession object.
    AVAudioSession * audioSession = [AVAudioSession sharedInstance];
    //Setup the audioSession for playback and record.
    //We could just use record and then switch it to playback leter, but
    //since we are going to do both lets set it up once.
    [audioSession setCategory:AVAudioSessionCategoryPlayAndRecord error: &error];
    //Activate the session
    [audioSession setActive:YES error: &error];

}
/*
// The designated initializer. Override to perform setup that is required before the view is loaded.
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}
*/

/*
// Implement loadView to create a view hierarchy programmatically, without using a nib.
- (void)loadView {
}
*/


/*
// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {
    [super viewDidLoad];
}
*/


/*
// Override to allow orientations other than the default portrait orientation.
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
    // Return YES for supported orientations
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
*/

- (IBAction)  start_button_pressed{

    if(toggle)
    {
        toggle = NO;
        [actSpinner startAnimating];
        [bthStart setTitle:@"停" forState: UIControlStateNormal ];
        bthPlay.enabled = toggle;
        bthPlay.hidden = !toggle;

        //Begin the recording session.
        //Error handling removed.  Please add to your own code.

        //Setup the dictionary object with all the recording settings that this
        //Recording sessoin will use
        //Its not clear to me which of these are required and which are the bare minimum.
        //This is a good resource: http://www.totodotnet.net/tag/avaudiorecorder/
        NSMutableDictionary* recordSetting = [[NSMutableDictionary alloc] init];

        [recordSetting setValue :[NSNumber numberWithInt:kAudioFormatAppleIMA4] forKey:AVFormatIDKey];

        [recordSetting setValue:[NSNumber numberWithFloat:[freq.text floatValue]] forKey:AVSampleRateKey];
        [recordSetting setValue:[NSNumber numberWithInt: [value.text intValue]] forKey:AVNumberOfChannelsKey];

        //Now that we have our settings we are going to instanciate an instance of our recorder instance.
        //Generate a temp file for use by the recording.
        //This sample was one I found online and seems to be a good choice for making a tmp file that
        //will not overwrite an existing one.
        //I know this is a mess of collapsed things into 1 call.  I can break it out if need be.
        recordedTmpFile = [NSURL fileURLWithPath:[NSTemporaryDirectory() stringByAppendingPathComponent: [NSString stringWithFormat: @"%.0f.%@", [NSDate timeIntervalSinceReferenceDate] * 1000.0, @"caf"]]];
        NSLog(@"Using File called: %@",recordedTmpFile);
        //Setup the recorder to use this file and record to it.
        recorder = [[ AVAudioRecorder alloc] initWithURL:recordedTmpFile settings:recordSetting error:&error];
        //Use the recorder to start the recording.
        //Im not sure why we set the delegate to self yet.
        //Found this in antother example, but Im fuzzy on this still.
        [recorder setDelegate:self];
        //We call this to start the recording process and initialize
        //the subsstems so that when we actually say "record" it starts right away.
        [recorder prepareToRecord];
        //Start the actual Recording
        [recorder record];
        //There is an optional method for doing the recording for a limited time see
        //[recorder recordForDuration:(NSTimeInterval) 10]

    }
    else
    {
        toggle = YES;
        [actSpinner stopAnimating];
        [bthStart setTitle:@"开始录音" forState:UIControlStateNormal ];
        bthPlay.enabled = toggle;
        bthPlay.hidden = !toggle;

        NSLog(@"Using File called: %@",recordedTmpFile);
        //Stop the recorder.
        [recorder stop];
    }
}

- (void)didReceiveMemoryWarning {
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];

    // Release any cached data, images, etc that aren't in use.
}

-(IBAction) play_button_pressed{

    //The play button was pressed...
    //Setup the AVAudioPlayer to play the file that we just recorded.
    AVAudioPlayer * avPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:recordedTmpFile error:&error];
    [avPlayer prepareToPlay];
    [avPlayer play];

}

- (void)viewDidUnload {
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
    //Clean up the temp file.
    NSFileManager * fm = [NSFileManager defaultManager];
    [fm removeItemAtPath:[recordedTmpFile path] error:&error];
    //Call the dealloc on the remaining objects.
    [recorder dealloc];
    recorder = nil;
    recordedTmpFile = nil;
}


- (void)dealloc {
    [super dealloc];
}

@end

最后在interface builder里面绘制好界面，如

设置下按键的属性

基本就ok了，可以开始录音了。

BUG解决

但是大家要注意一个貌似是ios5.0之后引入的bug，就是当你录制音频的时候启动时间往往会比较慢，大概需要3－－5秒的时间吧，这种现象尤其在播放的时候立刻切换到录制的时候非常明显。

 

具体的原因我也不是很清楚，感觉应该是更底层的一些bug。目前我的解决方案是这样的。

1.在音频队列的初始化方法中加入代码

OSStatus error = AudioSessionInitialize(NULL, NULL, NULL, NULL);

        UInt32 category = kAudioSessionCategory_PlayAndRecord;

error = AudioSessionSetProperty(kAudioSessionProperty_AudioCategory, sizeof(category), &category);

        

AudioSessionAddPropertyListener(kAudioSessionProperty_AudioRouteChange, NULL, self);

UInt32 inputAvailable = 0;

UInt32 size = sizeof(inputAvailable);

AudioSessionGetProperty(kAudioSessionProperty_AudioInputAvailable, &size, &inputAvailable);

AudioSessionAddPropertyListener(kAudioSessionProperty_AudioInputAvailable, NULL, self);

        AudioSessionSetActive(true); 

2.在录制声音开始的时候先把播放声音stop，加入

    UInt32 category = kAudioSessionCategory_PlayAndRecord;

    AudioSessionSetProperty(kAudioSessionProperty_AudioCategory, sizeof(category), &category);

 

这样做应该会让你的录制启动速度显著加快的。

 

csdn转载：http://blog.csdn.net/ch_soft/article/details/7382411