IOS15录音知识

//
//  ViewController.m
//  05-录音
//
//  Created by lujun on 2022/1/21.
//

#import "ViewController.h"
#import 
@interface ViewController ()
@property(nonatomic,strong)AVAudioRecorder *recoder;
@property(nonatomic,strong)CADisplayLink *displayLink;
//静音的持续时间
@property(nonatomic,assign)CGFloat slientDuration;
@end
@implementation ViewController
- (IBAction)startRecoord:(id)sender {
    NSString *doc = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
    NSString *path   = [doc stringByAppendingPathComponent:@"test3.caf"];
    NSURL *ulr1 = [NSURL fileURLWithPath:path];
    NSLog(@"%@",ulr1);
    // setting:录音的设置项
    NSDictionary *configDic = @{// 编码格式
        AVFormatIDKey:@(kAudioFormatLinearPCM),
        // 采样率
        AVSampleRateKey:@(11025.0),
        // 通道数
        AVNumberOfChannelsKey:@(2),
        // 录音质量
        AVEncoderAudioQualityKey:@(AVAudioQualityMin)
    };
    self.recoder = [[AVAudioRecorder alloc]initWithURL:ulr1 settings:configDic error:nil];
    //开启分贝测量功能
    self.recoder.meteringEnabled = YES;
    [self.recoder prepareToRecord];
    [self.recoder record];
    [self addTime];
    //    [self.recoder averagePowerForChannel:0];
}
- (IBAction)stopRecoard:(id)sender {
    [self.recoder stop];
    [self removeTime];
}
-(void)update1{
    // NSLog(@"%f",[self.recoder averagePowerForChannel:0]);
    //更新测量值
    [self.recoder updateMeters];
    float power =  [self.recoder averagePowerForChannel:0];
    if(power <= -20){ //几乎为静音
        self.slientDuration += self.displayLink.duration;
        
        if(self.slientDuration >= 2){
            //停止录音
            [self.recoder stop];
        }
    }else{
        self.slientDuration = 0;
    }
}
-(void) addTime{
    self.displayLink = [CADisplayLink displayLinkWithTarget:self selector:@selector(update1)];
    [self.displayLink addToRunLoop:[NSRunLoop mainRunLoop] forMode:NSRunLoopCommonModes];
}
-(void)removeTime{
    [self.displayLink invalidate];
    self.displayLink = nil;
}
@end