iOS錄音實踐

iOS錄音實踐

在AVFoundation架構中AVAudioRecorder類專門處理錄音操作，支援多種音頻格式。下面是常用的屬性和方法：

 

屬性	說明
@property(readonly, getter=isRecording) BOOL recording;	是否正在錄音，唯讀
@property(readonly) NSURL *url	錄音檔案地址，唯讀
@property(readonly) NSDictionary *settings	錄音檔案設定，唯讀
@property(readonly) NSTimeInterval currentTime	錄音時間長度，唯讀，注意僅僅在錄音狀態可用
@property(readonly) NSTimeInterval deviceCurrentTime	輸入設定的時間長度，唯讀，注意此屬性一直可訪問
@property(getter=isMeteringEnabled) BOOL meteringEnabled;	是否啟用錄音測量，如果啟用錄音測量可以獲得錄音分貝等資料資訊
@property(nonatomic, copy) NSArray *channelAssignments	當前錄音的通道
對象方法	說明
- (instancetype)initWithURL:(NSURL *)url settings:(NSDictionary *)settings error:(NSError **)outError	錄音機對象初始化方法，注意其中的url必須是本地檔案url，settings是錄音格式、編碼等設定
- (BOOL)prepareToRecord	準備錄音，主要用於建立緩衝區，如果不手動調用，在調用record錄音時也會自動調用
- (BOOL)record	開始錄音
- (BOOL)recordAtTime:(NSTimeInterval)time	在指定的時間開始錄音，一般用於錄音暫停再恢複錄音
- (BOOL)recordForDuration:(NSTimeInterval) duration	按指定的時間長度開始錄音
- (BOOL)recordAtTime:(NSTimeInterval)time forDuration:(NSTimeInterval) duration	在指定的時間開始錄音，並指定錄音時間長度
- (void)pause;	暫停錄音
- (void)stop;	停止錄音
- (BOOL)deleteRecording;	刪除錄音，注意要刪除錄音此時錄音機必須處於停止狀態
- (void)updateMeters;	更新測量資料，注意只有meteringEnabled為YES此方法才可用
- (float)peakPowerForChannel:(NSUInteger)channelNumber;	指定通道的測量峰值，注意只有調用完updateMeters才有值
- (float)averagePowerForChannel:(NSUInteger)channelNumber	指定通道的測量平均值，注意只有調用完updateMeters才有值
代理方法	說明
- (void)audioRecorderDidFinishRecording:(AVAudioRecorder *)recorder successfully:(BOOL)flag	完成錄音
- (void)audioRecorderEncodeErrorDidOccur:(AVAudioRecorder *)recorder error:(NSError *)error	錄音編碼發生錯誤

 

 

AVAudioRecorder建立錄音機時除了指定路徑外還必須指定錄音設定資訊，因為錄音機必須知道錄音檔案的格式、採樣率、通道數、每個採樣點的位元等資訊，通常只需要幾個常用設定。關於錄音設定詳見協助文檔中的“AV Foundation Audio Settings Constants”。

以下代碼實現錄音，暫停，繼續，取消，停止，播放功能。

 

#import ViewController.h#import #define kAudioFileName @test.caf@interface ViewController ()@property (nonatomic,strong) AVAudioRecorder *audioRecorder; //音頻錄音機@property (nonatomic,strong) AVAudioPlayer *audioPlayer;     //音頻播放器@property (nonatomic,strong) NSTimer *timer;            //錄音監控@property (weak, nonatomic) IBOutlet UIProgressView *audioPower;@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];    [self setAudioSession];}- (void)didReceiveMemoryWarning {    [super didReceiveMemoryWarning];    // Dispose of any resources that can be recreated.}/** *  設定音頻會話 */-(void)setAudioSession{    AVAudioSession *audioSession=[AVAudioSession sharedInstance];    //設定為播放和錄音狀態，以便可以在錄製完之後播放錄音    [audioSession setCategory:AVAudioSessionCategoryPlayAndRecord error:nil];    [audioSession setActive:YES error:nil];}/** *  錄音檔案設定 * *  @return 返回錄音設定 */- (NSDictionary *)getAudioSetting{    NSMutableDictionary *dic = [NSMutableDictionary dictionary];    [dic setObject:@(kAudioFormatLinearPCM) forKey:AVFormatIDKey];  //設定錄音格式    [dic setObject:@(8000) forKey:AVSampleRateKey];                 //設定採樣率    [dic setObject:@(1) forKey:AVNumberOfChannelsKey];              //設定通道，這裡採用單聲道    [dic setObject:@(8) forKey:AVLinearPCMBitDepthKey];             //每個採樣點位元，分為8，16，24，32    [dic setObject:@(YES) forKey:AVLinearPCMIsFloatKey];            //是否使用浮點數採樣    return dic;}/** *  錄音儲存路徑 * *  @return 返回儲存路徑 */- (NSURL *)getSavePath{    NSString *url = [NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory, NSUserDomainMask,YES) lastObject];    url = [url stringByAppendingPathComponent:kAudioFileName];    return [NSURL URLWithString:url];}- (NSTimer *)timer{    if (!_timer) {        _timer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(audioPowerChange) userInfo:nil repeats:YES];    }    return _timer;}- (AVAudioRecorder *)audioRecorder{    if (!_audioRecorder) {        NSError *error = nil;        _audioRecorder = [[AVAudioRecorder alloc] initWithURL:[self getSavePath] settings:[self getAudioSetting] error:&error];        _audioRecorder.delegate = self;        _audioRecorder.meteringEnabled = YES; //是否啟用錄音測量，如果啟用錄音測量可以獲得錄音分貝等資料資訊        if (error) {            NSLog(@建立錄音機對象發生錯誤:%@,error.localizedDescription);            return nil;        }    }    return _audioRecorder;}- (AVAudioPlayer *)audioPlayer{    if (!_audioPlayer) {        NSError *error = nil;        _audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:[self getSavePath] error:&error];        if (error) {            NSLog(@建立音頻播放器對象發生錯誤:%@,error.localizedDescription);            return nil;        }    }    return _audioPlayer;}#pragma mark - #pragma mark - AVAudioRecorderDelegate//錄音成功- (void)audioRecorderDidFinishRecording:(AVAudioRecorder *)recorder successfully:(BOOL)flag{    if (![self.audioPlayer isPlaying]) {        [self.audioPlayer play];    }}//錄音失敗- (void)audioRecorderEncodeErrorDidOccur:(AVAudioRecorder *)recorder error:(NSError *)error{    }#pragma mark - #pragma mark - Action- (void)audioPowerChange{    [self.audioRecorder updateMeters];  //更新測量值    float power = [self.audioRecorder averagePowerForChannel:1]; //取得第一個通道的音頻，注意音頻強度範圍時-160到0    self.audioPower.progress = (1.0/160)*(power+160);}/** *  點擊錄音按鈕 * *  @param sender 錄音按鈕 */- (IBAction)startRecord:(id)sender {        if (![self.audioRecorder isRecording]) {        [self.audioRecorder record];        self.timer.fireDate = [NSDate distantPast];    }}/** *  點擊取消錄音按鈕 * *  @param sender 取消錄音按鈕 */- (IBAction)cancelRecord:(id)sender {    self.audioRecorder.delegate = nil;    if ([self.audioRecorder isRecording]) {       [self.audioRecorder stop];    }    self.audioRecorder = nil;}/** *  點擊暫訂按鈕 * *  @param sender 暫停按鈕 */- (IBAction)pause:(id)sender {    if ([self.audioRecorder isRecording]) {        [self.audioRecorder pause];        self.timer.fireDate = [NSDate distantFuture];    }}/** *  點擊恢複按鈕 *  恢複錄音只需要再次調用record，AVAudioSession會協助你記錄上次錄音位置並追加錄音 * *  @param sender 恢複按鈕 */- (IBAction)goon:(id)sender {    [self startRecord:nil];}/** *  點擊停止按鈕 * *  @param sender 停止按鈕 */- (IBAction)stop:(id)sender {    if ([self.audioRecorder isRecording]) {        [self.audioRecorder stop];        self.timer = [NSDate distantFuture];    }}/** *  點擊播放按鈕 * *  @param sender 播放按鈕 */- (IBAction)play:(id)sender {        if (![self.audioPlayer isPlaying]) {        [self.audioPlayer play];    }}