iOS录音wav caf 及mp3转码 音频的曲线

一 : 定义一个全局变量AVAudioRecorder的录音对象,并启动录音

1. PCM格式设置如下:

//设置属性的字典
recordSetting = [[NSMutableDictionary alloc] init];

//1.格式
    [recordSetting setObject:[NSNumber numberWithInt:kAudioFormatLinearPCM] forKey:AVFormatIDKey];
    //2.采样率
    [recordSetting setObject:[NSNumber numberWithInt:1600] forKey:AVSampleRateKey];
    //3.声道 要转换mp3格式声道就必须设置为2
    [recordSetting setObject:[NSNumber numberWithInt:2] forKey:AVNumberOfChannelsKey];
    //4.采样位数
    [recordSetting setObject:[NSNumber numberWithInt:16] forKey:AVLinearPCMBitDepthKey];

非PCM格式 比如IMA4

    [recordSetting setValue :[NSNumber numberWithInt:kAudioFormatAppleIMA4] forKey:AVFormatIDKey];
    [recordSetting setValue:[NSNumber numberWithFloat:1600.0] forKey:AVSampleRateKey];
    [recordSetting setValue:[NSNumber numberWithInt: 1] forKey:AVNumberOfChannelsKey];

2.设置路径及其url,并清除上一次缓存录音文件,录取新的文件

NSString *recprderPath = [NSHomeDirectory() stringByAppendingPathComponent:@"recorder.wav"];
//路劲另一个方法:[NSString stringWithFormat:@"%@/Documents/MySound.caf", NSHomeDirectory()]];
}
NSURL *url = [NSURL fileURLWithPath:recprderPath];

NSError *err = nil;
    err = nil;
    //从路径下检查是否有文件
    NSData *audioData = [NSData dataWithContentsOfFile:[url path] options: 0 error:&err];
    if(audioData)
    {
    //如果有使用文件管理移除上一次录音文件
        NSFileManager *fm = [NSFileManager defaultManager];
        [fm removeItemAtPath:[url path] error:&err];
    }
    err = nil;
//用字典定义的属性配置录音(初始化)
    recorder = [[ AVAudioRecorder alloc] initWithURL:url settings:recordSetting error:&err];

//如果录音配置失败
    if(!recorder){
    //打印错误信息
        NSLog(@"recorder: %@ %ld %@", [err domain], [err code], [[err userInfo] description]);
        UIAlertView *alert =
        [[UIAlertView alloc] initWithTitle: @"Warning"
                                   message: [err localizedDescription]
                                  delegate: nil
                         cancelButtonTitle:@"OK"
                         otherButtonTitles:nil];
        [alert show];
        return;
    }

    [recorder setDelegate:self];//设置代理
    [recorder prepareToRecord];//准备录音
    recorder.meteringEnabled = YES;//开启音量检测
    [recorder recordForDuration:(NSTimeInterval) 180.0];//录音有效时长


//设置定时器,每0.05秒调用updateMeters的方法画出音频曲线
timer = [NSTimer scheduledTimerWithTimeInterval:0.05 target:self selector:@selector(updateMeters) userInfo:nil repeats:YES];
//这里的updateMeters是重写父类方法

二 : 关于定时器启动 以及音频曲线

1. 写父类方法  获得当前音频功率值,调用averagePowerForChannel之前你必须调用这个方法

- (void)updateMeters {
    [recorder updateMeters];
//如果录音的分贝小于-60并且时间超过180秒提交录音
   if (([recorder averagePowerForChannel:0] < -60.0) && (recordTime > 180.0)) {
        [self commitRecording];
        return;
    }
    recordTime += 0.05;//和定时器时间一样
    [self addSoundMeterItem:[recorder averagePowerForChannel:0]];
}

2. Sound meter operations

//定义一个宏和soundMeters[i]数值要一样
#define SOUND_METER_COUNT 40

- (void)shiftSoundMeterLeft {
    for(int i=0; i1; i++) {
        soundMeters[i] = soundMeters[i+1];
    }
}

- (void)addSoundMeterItem:(int)lastValue {
    [self shiftSoundMeterLeft];
    [self shiftSoundMeterLeft];
    soundMeters[SOUND_METER_COUNT - 1] = lastValue;
    soundMeters[SOUND_METER_COUNT - 2] = lastValue;
    [self setNeedsDisplay];
}

3. 设置取消按钮,即图中的标注中,以及其方法

#define HUD_SIZE 220
#define CANCEL_BUTTON_HEIGHT 40

        //麦克风位置
        CGRect hudRect;
        hudRect = CGRectMake(self.center.x - (HUD_SIZE / 2), self.center.y - (HUD_SIZE / 2) - 20, HUD_SIZE, HUD_SIZE);
        int x = (frame.size.width - HUD_SIZE) / 2;
        btnCancel = [[UIButton alloc] initWithFrame:CGRectMake(x, hudRect.origin.y + HUD_SIZE - CANCEL_BUTTON_HEIGHT, HUD_SIZE, CANCEL_BUTTON_HEIGHT)];
        [btnCancel setTitle:NSLocalizedString(@"标注中", nil) forState:UIControlStateNormal];
        [btnCancel addTarget:self action:@selector(cancelled:) forControlEvents:UIControlEventTouchUpInside];
        btnCancel.enabled = NO;
        [self addSubview:btnCancel];

//取消按钮点击事件
- (void)cancelled:(id)sender {
    self.alpha = 0.0;
    [self setNeedsDisplay];

    [timer invalidate];
    [self cancelRecording];
}

//取消事件
- (void)cancelRecording {
  //配合代理使用事件
    if ([self.delegate respondsToSelector:@selector(voiceRecordCancelledByUser:)]) {
        [self.delegate voiceRecordCancelledByUser:self];
    }

    [recorder stop];
}


4. 画出录音曲线  以及  
- (void)drawRect:(CGRect)rect {
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
    CGContextRef context = UIGraphicsGetCurrentContext();//上下文

    UIColor *strokeColor = [UIColor colorWithRed:0.886 green:0.0 blue:0.0 alpha:0.8];
    UIColor *fillColor = [UIColor colorWithRed:0.5827 green:0.5827 blue:0.5827 alpha:1.0];
    UIColor *gradientColor = [UIColor colorWithRed:0.0 green:0.0 blue:0.0 alpha:0.8];
    UIColor *color = [UIColor colorWithRed:1.0 green:1.0 blue:1.0 alpha:1.0];


    NSArray *gradientColors = [NSArray arrayWithObjects:
                               (id)fillColor.CGColor,
                               (id)gradientColor.CGColor, nil];
    CGFloat gradientLocations[] = {0, 1};
    CGGradientRef gradient = CGGradientCreateWithColors(colorSpace, (__bridge CFArrayRef)gradientColors, gradientLocations);

    UIBezierPath *border = [UIBezierPath bezierPathWithRoundedRect:hudRect cornerRadius:10.0];
    CGContextSaveGState(context);
    [border addClip];
    CGContextDrawRadialGradient(context, gradient,
                                CGPointMake(hudRect.origin.x+HUD_SIZE/2, 120), 10,
                                CGPointMake(hudRect.origin.x+HUD_SIZE/2, 195), 215,
                                kCGGradientDrawsBeforeStartLocation | kCGGradientDrawsAfterEndLocation);

    CGContextRestoreGState(context);
    [strokeColor setStroke];
    border.lineWidth = 3.0;
    [border stroke];

    // 画出音频波浪 
    [[UIColor colorWithRed:1.0 green:1.0 blue:1.0 alpha:0.4] set];

    CGContextSetLineWidth(context, 3.0);
    CGContextSetLineJoin(context, kCGLineJoinRound);

    int baseLine = 250;//不同的机型 定义不一样 距离screen上端距离可能是310mm
    int multiplier = 1;
    int maxLengthOfWave = 50;
    int maxValueOfMeter = 70;
    for(CGFloat x = SOUND_METER_COUNT - 1; x >= 0; x--)
    {
        multiplier = ((int)x % 2) == 0 ? 1 : -1;

        CGFloat y = baseLine + ((maxValueOfMeter * (maxLengthOfWave - abs(soundMeters[(int)x]))) / maxLengthOfWave) * multiplier;

        if(x == SOUND_METER_COUNT - 1) {
            CGContextMoveToPoint(context, x * (HUD_SIZE / SOUND_METER_COUNT) + hudRect.origin.x + 10, y);
            CGContextAddLineToPoint(context, x * (HUD_SIZE / SOUND_METER_COUNT) + hudRect.origin.x + 7, y);
        }
        else {
            CGContextAddLineToPoint(context, x * (HUD_SIZE / SOUND_METER_COUNT) + hudRect.origin.x + 10, y);
            CGContextAddLineToPoint(context, x * (HUD_SIZE / SOUND_METER_COUNT) + hudRect.origin.x + 7, y);
        }
    }

    CGContextStrokePath(context);

    // 画出标题 即图中大字标注中
    [color setFill];
    [self.title drawInRect:CGRectInset(hudRect, 0, 20) withFont:[UIFont systemFontOfSize:30.0] lineBreakMode:UILineBreakModeWordWrap alignment:UITextAlignmentCenter];//标题的位置文字大小 等等

    [imgMicrophone drawAtPoint:CGPointMake(hudRect.origin.x + hudRect.size.width/2 - imgMicrophone.size.width/2, hudRect.origin.y + hudRect.size.height/2 - imgMicrophone.size.height/2)];

    [[UIColor colorWithWhite:0.8 alpha:1.0] setFill];
    UIBezierPath *line = [UIBezierPath bezierPath];
    [line moveToPoint:CGPointMake(hudRect.origin.x, hudRect.origin.y + HUD_SIZE - CANCEL_BUTTON_HEIGHT)];
    [line addLineToPoint:CGPointMake(hudRect.origin.x + HUD_SIZE, hudRect.origin.y + HUD_SIZE - CANCEL_BUTTON_HEIGHT)];
    [line setLineWidth:3.0];
    [line stroke];
}

三 : 录音完成之后 开始转码 mp3

//导入头文件lame.h和其静态库
- (BOOL)audio_PCMtoMP3
{
    NSString *mp3FilePath = [NSHomeDirectory() stringByAppendingPathComponent:@"mp3FilePath.mp3"];
    mp3Path = mp3FilePath;
    NSFileManager * fileManager=[ NSFileManager defaultManager ];

    if ([fileManager removeItemAtPath :mp3FilePath error : nil ])
    {
        NSLog ( @" 删除 " );
    }

    @try {

        int read, write;

        FILE *pcm = fopen ([recorderFilePath cStringUsingEncoding : 1 ], "rb" );
        //source 被 转换的音频文件位置

        if (pcm == NULL )
        {

            NSLog ( @"file not found" );

        }
        else
        {

            fseek (pcm, 4 * 1024 , SEEK_CUR );
            //skip file header

            FILE *mp3 = fopen ([mp3FilePath cStringUsingEncoding : 1 ], "wb" );
            //output 输出生成的 Mp3 文件位置

            const int PCM_SIZE = 8192 ;

            const int MP3_SIZE = 8192 ;

            short int pcm_buffer[PCM_SIZE* 2 ];

            unsigned char mp3_buffer[MP3_SIZE];



            lame_t lame  = lame_init ();

            lame_set_num_channels (lame, 1 ); // 设置 1 为单通道，默认为 2 双通道

            lame_set_in_samplerate (lame, 1600.0 ); //11025.0取频 采样

            //lame_set_VBR(lame, vbr_default);

            lame_set_brate (lame, 8 );

            lame_set_mode (lame, 3 );

            lame_set_quality (lame, 2 ); /* 2=high 5 = medium 7=low 音 质 */

            lame_init_params (lame);



            do {

                read = fread (pcm_buffer, 2 * sizeof ( short int ), PCM_SIZE, pcm);

                if (read == 0 )

                    write = lame_encode_flush (lame, mp3_buffer, MP3_SIZE);

                else

                    write = lame_encode_buffer_interleaved (lame, pcm_buffer, read, mp3_buffer, MP3_SIZE);



                fwrite (mp3_buffer, write, 1 , mp3);



            } while (read != 0 );



            lame_close (lame);//释放lame

            fclose (mp3);

            fclose (pcm);

            return YES ;

        }

        return NO ;

    }

    @catch (NSException *exception) {

        NSLog ( @"%@" ,[exception description ]);

        return NO ;

    }

    @finally {

        NSLog ( @" 转码执行完成 " );

    }

}