文章結(jié)束后實現(xiàn)：

• 用戶點擊 錄音按鈕 錄制聲音
• 松開 錄音按鈕 的時候，音頻文件轉(zhuǎn)換為 mp3 格式上傳到服務(wù)器
• 點擊 播發(fā)按鈕 播放之前錄制的聲音文件

需要的類

1： 導入 AVFoundation 框架，使用：

• AVAudioRecorder， 聲音錄制
• AVAudioPlayer， 聲音播放

2： 需要 lame 進行聲音轉(zhuǎn)化

plist 配置

允許使用麥克風

屏幕快照 2017-07-19 下午5.10.08.png

代碼

示例代碼：

import UIKit
import AVFoundation

class ViewController: UIViewController {
    
    private var session: AVAudioSession!

    private var recorder: AVAudioRecorder!
    private var player: AVAudioPlayer!
    
    private var pcmPath: String!
    private var mp3FilePath: String!
    
    private var recorderSetting: [String: AnyObject]!
    
    private var mp3FileURL: URL!
    
    private let avSampleRateKey = 44100
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        session = AVAudioSession.sharedInstance()
        try! session.setActive(true)
        
        let docDic = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0]
        
        pcmPath = docDic + "/play.pcm"
        mp3FilePath = docDic + "/play.mp3"
        
        mp3FileURL = URL(fileURLWithPath: mp3FilePath)
        
        recorderSetting =
            [
                AVFormatIDKey: NSNumber(value: kAudioFormatLinearPCM),
                AVNumberOfChannelsKey: 2 as AnyObject, //錄音的聲道數(shù)，立體聲為雙聲道
                AVEncoderAudioQualityKey : AVAudioQuality.max.rawValue as AnyObject,
                AVEncoderBitRateKey : 640000 as AnyObject,
                AVSampleRateKey : avSampleRateKey as AnyObject //錄音器每秒采集的錄音樣本數(shù)
        ]
    }
    
    
    @IBAction func touchDown() {
        do {
            try session.setCategory(AVAudioSessionCategoryPlayAndRecord)
            
            recorder = try AVAudioRecorder(url: URL(string: pcmPath)!, settings: recorderSetting)
            recorder.isMeteringEnabled = true
            recorder.record()
        } catch let error {
            print("create recorder error: \(error)")
        }
    }
    
    @IBAction func touchUp() {
        recorder.stop()
        
        DispatchQueue.global().async {
            let success = AudioTransform.transformToMp3(fromPath: self.pcmPath,
                                                        toMp3Path: self.mp3FilePath,
                                                        withAVSampleRateKey: Int32(self.avSampleRateKey))
            
            DispatchQueue.main.async {
                print("transform success")
                if success {
                    do {
                        let data = try Data(contentsOf: self.mp3FileURL!)
                        print("data: \(data)")
                        DemoModel.uploadRecord(data: data) { (success, info) in
                            
                        }
                    } catch let error {
                        print("upload audio error: \(error)")
                    }
                }
            }
        }
    }
    
    @IBAction func play() {
        do {
            try session.setCategory(AVAudioSessionCategoryPlayback)
            
            player = try AVAudioPlayer(contentsOf: recorder.url)
            player.play()
        } catch let error {
            print("paly audio error: \(error)")
        }
    }
}

注意需要為 錄制按鈕 實現(xiàn):

• touchDown 事件（按住按鈕觸發(fā)）
• touchUpInside 事件（松開按鈕觸發(fā)）

轉(zhuǎn)化為 mp3 代碼：

#import "lame.h"

@implementation AudioTransform

+ (BOOL)transformToMp3FromPath:(NSString *)originalPath
                     toMp3Path:(NSString *)mp3Path
           withAVSampleRateKey:(int)rateKey {
    @try {
        int read, write;
        
        FILE *pcm = fopen([originalPath cStringUsingEncoding:1], "rb");  //source
        fseek(pcm, 4*1024, SEEK_CUR);                                    //skip file header
        FILE *mp3 = fopen([mp3Path cStringUsingEncoding:1], "wb");       //output
        
        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_in_samplerate(lame, rateKey);
        lame_set_VBR(lame, vbr_default);
        lame_init_params(lame);
        
        do {
            read = (int)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);
        fclose(mp3);
        fclose(pcm);
    }
    @catch (NSException *exception) {
        NSLog(@"%@",[exception description]);
        return false;
    }
    @finally {
        return true;
    }

}


@end

注意：需要使用 lame 這個小插件實現(xiàn)轉(zhuǎn)化，lame下載地址。你也可以直接使用Demo內(nèi)的 fat-lame 里面是已經(jīng)編譯好的文件 (轉(zhuǎn)化文件是用 Objective-C 寫的，在 Swift 項目中需要一個bridge 文件)

屏幕快照 2017-07-19 下午5.33.17.png

錄制完聲音后，如果播放的時候發(fā)現(xiàn) 聲音變小
在播放聲音的方法內(nèi)設(shè)置：

try! session.setCategory(AVAudioSessionCategoryPlayback)

錄制聲音的方法內(nèi)設(shè)置：

try! session.setCategory(AVAudioSessionCategoryPlayAndRecord)

Demo 地址

參考鏈接：
音頻的文件格式和數(shù)據(jù)格式