一、录音设置

    NSMutableDictionary *recordSetting = [[NSMutableDictionary alloc]init];

    //设置录音格式  AVFormatIDKey==kAudioFormatLinearPCM

    [recordSetting setValue:[NSNumber numberWithInt:kAudioFormatMPEG4AAC] forKey:AVFormatIDKey];

    //设置录音采样率(Hz) 如：AVSampleRateKey==8000/44100/96000（影响音频的质量）

    [recordSetting setValue:[NSNumber numberWithFloat:16000] forKey:AVSampleRateKey];

    //录音通道数  1 或 2

    [recordSetting setValue:[NSNumber numberWithInt:1] forKey:AVNumberOfChannelsKey];

    //线性采样位数  8、16、24、32

    [recordSetting setValue:[NSNumber numberWithInt:16] forKey:AVLinearPCMBitDepthKey];

    //录音的质量

    [recordSetting setValue:[NSNumber numberWithInt:AVAudioQualityHigh] forKey:AVEncoderAudioQualityKey];

    NSString *strUrl = [NSString stringWithFormat:@"%@/%@.wav", [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject], [NSString uuid]];

    NSURL *url = [NSURL fileURLWithPath:strUrl];

    self.recordUrlKey = strUrl;

//    self.audioRecord.filePath = strUrl;

    NSError *error;

    //初始化

    _recorder = [[AVAudioRecorder alloc]initWithURL:url settings:recordSetting error:&error];

    //开启音量检测

    self.recorder.meteringEnabled = YES;

    if ([self.recorder prepareToRecord]){

        return YES;

    }

二、wav 转 m4a 格式

NSURL *audioPath = [NSURL fileURLWithPath:path];

    AVURLAsset* audioAsset = [[AVURLAsset alloc] initWithURL:audioPath options:nil];

    AVAssetExportSession* exportSession = [[AVAssetExportSession alloc] initWithAsset:audioAsset presetName:AVAssetExportPresetAppleM4A];

    NSURL* exportURL = [NSURL fileURLWithPath:[[path componentsSeparatedByString:@".wav"] objectAtIndex:0]];

    NSURL* destinationURL = [exportURL URLByAppendingPathExtension:@"m4a"];

    exportSession.outputURL = destinationURL;

    exportSession.outputFileType = AVFileTypeAppleM4A;

    [exportSession exportAsynchronouslyWithCompletionHandler:^{

        if (AVAssetExportSessionStatusCompleted == exportSession.status) {

        } else if (AVAssetExportSessionStatusFailed == exportSession.status) {

        } else {

        }

        didFinish();

    }];

三、m4a 翻译

NSURL *exportURL = [NSURL fileURLWithPath:[[path componentsSeparatedByString:@".wav"] objectAtIndex:0]];

            NSURL *destinationURL = [exportURL URLByAppendingPathExtension:@"m4a"];

            NSLocale *local =[[NSLocale alloc] initWithLocaleIdentifier:@"zh_CN"];

            SFSpeechRecognizer *localRecognizer =[[SFSpeechRecognizer alloc] initWithLocale:local];

            NSURL *url = destinationURL;

            if (!url) { [AlertUtil showAlertWithText:@"转换失败"]; return;}

            SFSpeechURLRecognitionRequest *res =[[SFSpeechURLRecognitionRequest alloc] initWithURL:url];

            __weak typeof(self) weakSelf = self;

            [localRecognizer recognitionTaskWithRequest:res resultHandler:^(SFSpeechRecognitionResult * _Nullable result, NSError * _Nullable error) {

                if (error) {

                    NSLog(@"------------------------语音识别解析======失败,%@",error);

                    [AlertUtil showAlertWithText:@"转换失败"];

                } else {

                    NSLog(@"------------------------语音识别解析======成功,%@",result.bestTranscription.formattedString);

                    [weakSelf showWord:result.bestTranscription.formattedString];

                }

            }];