iOS：百度长语音识别具体的封装：识别、播放、进度刷新

一、介绍

以前做过讯飞语音识别，比较简单，识别率很不错，但是它的识别时间是有限制的，最多60秒。可是有的时候我们需要更长的识别时间，例如朗诵古诗等功能。当然讯飞语音也是可以通过曲线救国来实现，就是每达到60秒时识别停止就立即重新开启，每次结束拼接录音。这么做，显然是麻烦的，百度语音解决了这个问题，它最近上线了长语音识别技术，可以不受时间限制，还是非常棒的。这次，我就专门抽成一个工具类使用，包括语音识别，录音拼接，录音播放、进度刷新，具体如何集成SDK看官方文档，我就不废话了，直接介绍如何使用我的这个工具类。

二、依赖

因为语音录制格式是pcm格式的，我使用lame静态库将其转成了mp3格式。

下载路径参考我的博客，有具体的介绍：http://www.cnblogs.com/XYQ-208910/p/7650759.html

三、代码

SJVoiceTransform.h

#import <Foundation/Foundation.h>

@interface SJVoiceTransform : NSObject

/**
 *  根据路径将pcm文件转化为MP3
 *
 *  @param docPath docment路径
 */
+(NSString *)stransformToMp3ByUrlWithUrl:(NSString *)docPath;

@end

SJVoiceTransform.m

#import "SJVoiceTransform.h"
#import "lame.h"
@interface SJVoiceTransform()

//@property (strong , nonatomic)NSString * path;//存放音频沙河路径
@end

@implementation SJVoiceTransform

+(NSString *)stransformToMp3ByUrlWithUrl:(NSString *)docPath
{
    NSString *pathUrl = [NSString stringWithFormat:@"%@",docPath];//存储录音pcm格式音频地址
    NSString * mp3Url = pathUrl;
    NSString *mp3FilePath = [docPath stringByAppendingString:@".mp3"];//存放Mp3地址
    if (!mp3Url || !mp3FilePath) {
        return ;
    }
    @try {
        unsigned long read, write;
        FILE *pcm = fopen([mp3Url cStringUsingEncoding:], "rb"); //source 被转换的音频文件位置
        //音频不能为空
        if (!pcm) {
            return nil;
        }
        fseek(pcm, *, SEEK_CUR); //skip file header
        FILE *mp3 = fopen([mp3FilePath cStringUsingEncoding:], "wb"); //output 输出生成的Mp3文件位置
        const int PCM_SIZE = ;
        const int MP3_SIZE = ;
        short int pcm_buffer[PCM_SIZE*];
        unsigned char mp3_buffer[MP3_SIZE];
        lame_t lame = lame_init();
        lame_set_num_channels(lame,);
        lame_set_in_samplerate(lame, 8000.0); //11025.0
        //lame_set_VBR(lame, vbr_default);
        lame_set_brate(lame, );
        lame_set_mode(lame, );
        lame_set_quality(lame, );//
        lame_init_params(lame);
        do {
            read = fread(pcm_buffer, *sizeof(short int), PCM_SIZE, pcm);
            if (read == )
                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, , mp3);
        } while (read != );
        lame_close(lame);
        fclose(mp3);
        fclose(pcm);
    }
    @catch (NSException *exception) {
        NSLog(@"%@",[exception description]);
    }
    @finally {
        NSLog(@"MP3生成成功: %@",mp3FilePath);
    }
    return mp3FilePath;

}

@end

BDHelper.h

//
//  BDHelper.h
//  BDRecognizer
//
//  Created by 夏远全 on 2017/11/14.
//  Copyright © 2017年 夏远全. All rights reserved.

#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>
#import <AudioToolbox/AudioToolbox.h>
#import <AVFoundation/AVFoundation.h>

@protocol BDHelperDelegate <NSObject>
@optional
-(void)recognitionPartialResult:(NSString *)recognitionResult; //中间结果
-(void)recognitionFinalResult:(NSString *)recognitionResult;   //最终结果
-(void)recognitionError:(NSError *)error;                      //识别错误
-(void)updateProgress:(CGFloat)progress duration:(int)duration;//更新播放进度
-(void)updateReadingTime:(int)readingTime;//更新朗诵时间
-(void)recognitionRecordFinishedPlay;//语音识别录音播放完成
@end

@interface BDHelper : NSObject

/**
 代理
 */
@property (nonatomic,   weak) id<BDHelperDelegate> delegate;

/**
 播放器
 */
@property (nonatomic, strong) AVAudioPlayer   *audioPlayer;

/**
 文件路径
 */
@property (nonatomic,   copy) NSString       *audioFilePath;

/**
 创建对象
 @param voiceFileName 录音文件名
 @return 实例
 */
+(BDHelper *)sharedBDHelperWithVoiceFileName:(NSString *)voiceFileName;

/**
 开始语音识别
 */
- (void)startLongSpeechRecognition;

/**
 结束语音识别
 */
- (void)endLongSpeechRecognition;

/**
 播放识别语音
 */
-(void)playListenningRecognition;

/**
 暂停语音播放
 */
-(void)pauseListenningRecognition;

/**
 @param isNeedDeleteFilePath 是否需要移除缓存的音频文件
 销毁播放器
 */
-(void)didRemoveAudioPlayer:(BOOL)isNeedDeleteFilePath;

/**
 启动计时器，累计朗诵时间
 */
- (void)beginStatisticsReadingTime;

/**
 销毁计时器
 */
- (void)endStatisticsReadingTime;

@end

BDHelper.m

//
//  BDHelper.m
//  BDRecognizer
//
//  Created by 夏远全 on 2017/11/14.
//  Copyright © 2017年 夏远全. All rights reserved.
//

#import "BDHelper.h"
#import "SJVoiceTransform.h"

#if !TARGET_IPHONE_SIMULATOR

#import "BDSEventManager.h"
#import "BDSASRDefines.h"
#import "BDSASRParameters.h"

/// "请在官网新建应用，配置包名，并在此填写应用的 api key, secret key, appid(即appcode)"
static NSString* const API_KEY    =     @"BxLweqmGUxxxxxxxxxxxxxx";
static NSString* const SECRET_KEY = @"rhUIXG4gXmxxxxxxxxxxxxxx";
static NSString* const APP_ID     =     @"81xxxxx";

@interface BDHelper()<BDSClientASRDelegate,AVAudioPlayerDelegate>
@property (nonatomic, strong) BDSEventManager      *asrEventManager;
@property (nonatomic, strong) CADisplayLink        *progressLink;
@property (nonatomic, strong) NSTimer              *readingTimer;
@property (nonatomic, strong) NSMutableData        *mutabelData;
@property (nonatomic, strong) NSFileHandle         *fileHandler;
@property (nonatomic,   copy) NSString             *voiceFileName;
@end

#endif

@implementation BDHelper

#if !TARGET_IPHONE_SIMULATOR

+(BDHelper *)sharedBDHelperWithVoiceFileName:(NSString *)voiceFileName{
    BDHelper *helper = [[self alloc] init];
    helper.voiceFileName = voiceFileName;
    [helper setupDefalutValue];
    return helper;
}

-(void)setupDefalutValue{

    self.asrEventManager = [BDSEventManager createEventManagerWithName:BDS_ASR_NAME];
    [self configVoiceRecognitionClient];
    NSLog(@"current sdk version: %@", [self.asrEventManager libver]);

}

#pragma mark - public: Method
- (void)startLongSpeechRecognition{

    //移除播放器
    [self didRemoveAudioPlayer:NO];

    //设置录音路径
    if (!_audioFilePath) {
        [self pcmFilePathConfig];
    }

    //启动识别服务
    [self beginStatisticsReadingTime];
    [self.asrEventManager sendCommand:BDS_ASR_CMD_START];
}

- (void)endLongSpeechRecognition{

    //关闭识别服务
    [self endStatisticsReadingTime];
    [self.asrEventManager sendCommand:BDS_ASR_CMD_STOP];
    [self.fileHandler writeData:self.mutabelData];
    self.mutabelData = nil;

}

-(void)playListenningRecognition{

    //避免重复点击
    if (_audioPlayer && _audioPlayer.isPlaying) {
        return;
    }

    //直接播放
    if (_audioPlayer && !_audioPlayer.isPlaying) {
        [_audioPlayer play];
         _progressLink.paused = NO;
        return;
    }

    //播放识别语音(pcm格式转成mp3格式)
    NSString *mp3Path = [SJVoiceTransform stransformToMp3ByUrlWithUrl:_audioFilePath];
    if (!mp3Path) {
        return;
    }

    //初始化播放器
    _audioPlayer = [[AVAudioPlayer alloc]initWithContentsOfURL:[NSURL fileURLWithPath:mp3Path] error:NULL];
    _audioPlayer.volume = ;
    _audioPlayer.delegate = self;
    [[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayback error:nil];
    [[AVAudioSession sharedInstance] setActive:YES error:nil];
    [_audioPlayer prepareToPlay];
    [_audioPlayer play];
    _progressLink = [CADisplayLink displayLinkWithTarget:self selector:@selector(updateProgressValue)];
    [_progressLink addToRunLoop:[NSRunLoop currentRunLoop] forMode:NSRunLoopCommonModes];
}

-(void)pauseListenningRecognition{

    //暂停播放
    if (_audioPlayer && _audioPlayer.isPlaying) {
        [_audioPlayer pause];
        _progressLink.paused = YES;
    }
}

#pragma mark - event
-(void)updateProgressValue{

    //更新播放进度
    int duration = round(_audioPlayer.duration);
    if (self.delegate && [self.delegate respondsToSelector:@selector(updateProgress:duration:)]) {
        [self.delegate updateProgress:_audioPlayer.currentTime/_audioPlayer.duration duration:duration];
    }
}

-(void)startReadingTimer{

    //累计朗诵时间
    if (self.delegate && [self.delegate respondsToSelector:@selector(updateReadingTime:)]) {
        [self.delegate updateReadingTime:];
    }
}

#pragma mark - Private: Configuration
- (void)configVoiceRecognitionClient {

    // ---- 设置DEBUG_LOG的级别
    [self.asrEventManager setParameter:@(EVRDebugLogLevelTrace) forKey:BDS_ASR_DEBUG_LOG_LEVEL];

    // ---- 配置API_KEY 和 SECRET_KEY 和 APP_ID
    [self.asrEventManager setParameter:@[API_KEY, SECRET_KEY] forKey:BDS_ASR_API_SECRET_KEYS];
    [self.asrEventManager setParameter:APP_ID forKey:BDS_ASR_OFFLINE_APP_CODE];

    // ---- 配置端点检测（二选一）
    [self configModelVAD];
    //[self configDNNMFE];

    // ---- 语义与标点 -----
    [self enableNLU];
    [self enablePunctuation];

    // ---- 长语音请务必开启本地VAD -----
    [self.asrEventManager setParameter:@(YES) forKey:BDS_ASR_ENABLE_LONG_SPEECH];
    [self.asrEventManager setParameter:@(YES) forKey:BDS_ASR_ENABLE_LOCAL_VAD];

    // ---- 录音文件路径 -----
    [self pcmFilePathConfig];

    // ---- 设置代理 -----
    [self.asrEventManager setDelegate:self];
    [self.asrEventManager setParameter:nil forKey:BDS_ASR_AUDIO_FILE_PATH];
    [self.asrEventManager setParameter:nil forKey:BDS_ASR_AUDIO_INPUT_STREAM];
}

- (void)pcmFilePathConfig{

    [self configFileHandler:self.voiceFileName];
    _audioFilePath = [self getFilePath:self.voiceFileName];
}

- (void)enableNLU {

    // ---- 开启语义理解 -----
    [self.asrEventManager setParameter:@(YES) forKey:BDS_ASR_ENABLE_NLU];
    [self.asrEventManager setParameter:@"" forKey:BDS_ASR_PRODUCT_ID];
}

- (void)enablePunctuation {

    // ---- 开启标点输出 -----
    [self.asrEventManager setParameter:@(NO) forKey:BDS_ASR_DISABLE_PUNCTUATION];

    // ---- 普通话标点 -----
    [self.asrEventManager setParameter:@"" forKey:BDS_ASR_PRODUCT_ID];
}

- (void)configModelVAD {

    NSString *modelVAD_filepath = [[NSBundle mainBundle] pathForResource:@"bds_easr_basic_model" ofType:@"dat"];
    [self.asrEventManager setParameter:modelVAD_filepath forKey:BDS_ASR_MODEL_VAD_DAT_FILE];
    [self.asrEventManager setParameter:@(YES) forKey:BDS_ASR_ENABLE_MODEL_VAD];
}

- (void)configDNNMFE {

    NSString *mfe_dnn_filepath = [[NSBundle mainBundle] pathForResource:@"bds_easr_mfe_dnn" ofType:@"dat"];
    NSString *cmvn_dnn_filepath = [[NSBundle mainBundle] pathForResource:@"bds_easr_mfe_cmvn" ofType:@"dat"];
    [self.asrEventManager setParameter:mfe_dnn_filepath forKey:BDS_ASR_MFE_DNN_DAT_FILE];
    [self.asrEventManager setParameter:cmvn_dnn_filepath forKey:BDS_ASR_MFE_CMVN_DAT_FILE];

    //自定义静音时长（单位：每帧10ms）
    //[self.asrEventManager setParameter:@(500) forKey:BDS_ASR_MFE_MAX_SPEECH_PAUSE];
    //[self.asrEventManager setParameter:@(501) forKey:BDS_ASR_MFE_MAX_WAIT_DURATION];
}

#pragma mark - MVoiceRecognitionClientDelegate
- (void)VoiceRecognitionClientWorkStatus:(int)workStatus obj:(id)aObj {

    switch (workStatus) {
        case EVoiceRecognitionClientWorkStatusNewRecordData: {
            /// 录音数据回调、NSData-原始音频数据，此处可以用来存储录音
            NSData *originData = (NSData *)aObj;
            [self.mutabelData appendData:originData];
            break;
        }
        case EVoiceRecognitionClientWorkStatusStartWorkIng: {
            /// 识别工作开始，开始采集及处理数据
            NSDictionary *logDic = [self parseLogToDic:aObj];
            NSLog(@"%@",[NSString stringWithFormat:@"CALLBACK: start vr, log: %@\n", logDic]);
            break;
        }
        case EVoiceRecognitionClientWorkStatusStart: {
            /// 检测到用户开始说话
            NSLog(@"CALLBACK: detect voice start point.\n");
            break;
        }
        case EVoiceRecognitionClientWorkStatusEnd: {
            /// 本地声音采集结束
            NSLog(@"CALLBACK: detect voice end point.\n");
            break;
        }
        case EVoiceRecognitionClientWorkStatusFlushData: {
            /// 连续上屏、NSDictionary-中间结果
            NSString *result = [self getDescriptionForDic:aObj];
            NSLog(@"%@",[NSString stringWithFormat:@"CALLBACK: partial result -%@.\n\n" ,result]);
            NSMutableString *recognitionResult = [aObj[@"results_recognition"] firstObject];
            if (self.delegate && [self.delegate respondsToSelector:@selector(recognitionPartialResult:)]) {
                [self.delegate recognitionPartialResult:recognitionResult];
            }
            break;
        }
        case EVoiceRecognitionClientWorkStatusFinish: {
            /// 语音识别功能完成，服务器返回正确结果、NSDictionary-最终识别结果
            NSString *result = [self getDescriptionForDic:aObj];
            NSLog(@"%@",[NSString stringWithFormat:@"CALLBACK: final result - %@.\n\n",result]);

            NSString *recognitionResult = [aObj[@"results_recognition"] firstObject];
            if (self.delegate && [self.delegate respondsToSelector:@selector(recognitionFinalResult:)]) {
                [self.delegate recognitionFinalResult:recognitionResult];
            }
            break;
        }
        case EVoiceRecognitionClientWorkStatusMeterLevel: {
            /// 当前音量回调、NSNumber:int-当前音量
            NSLog(@"-------voice volume:%d-------",[aObj intValue]);
            break;
        }
        case EVoiceRecognitionClientWorkStatusCancel: {
            /// 用户主动取消
            NSLog(@"CALLBACK: user press cancel.\n");
            break;
        }
        case EVoiceRecognitionClientWorkStatusError: {
            /// 发生错误 NSError-错误信息
            NSLog(@"%@", [NSString stringWithFormat:@"CALLBACK: encount error - %@.\n", (NSError *)aObj]);
            if (self.delegate && [self.delegate respondsToSelector:@selector(recognitionError:)]) {
                [self.delegate recognitionError:(NSError *)aObj];
            }
            break;
        }
        case EVoiceRecognitionClientWorkStatusLoaded: {
            /// 离线引擎加载完成
            NSLog(@"CALLBACK: offline engine loaded.\n");
            break;
        }
        case EVoiceRecognitionClientWorkStatusUnLoaded: {
            /// 离线引擎卸载完成
            NSLog(@"CALLBACK: offline engine unLoaded.\n");
            break;
        }
        case EVoiceRecognitionClientWorkStatusChunkThirdData: {
            /// CHUNK: 识别结果中的第三方数据  NSData
            NSLog(@"%@",[NSString stringWithFormat:@"CALLBACK: Chunk 3-party data length: %lu\n", (unsigned long)[(NSData *)aObj length]]);
            break;
        }
        case EVoiceRecognitionClientWorkStatusChunkNlu: {
            /// CHUNK: 识别结果中的语义结果  NSData
            NSString *nlu = [[NSString alloc] initWithData:(NSData *)aObj encoding:NSUTF8StringEncoding];
            NSLog(@"%@",[NSString stringWithFormat:@"CALLBACK: Chunk NLU data: %@\n", nlu]);
            break;
        }
        case EVoiceRecognitionClientWorkStatusChunkEnd: {
            /// CHUNK: 识别过程结束 NSString
            NSLog(@"%@",[NSString stringWithFormat:@"CALLBACK: Chunk end, sn: %@.\n", aObj]);
            break;
        }
        case EVoiceRecognitionClientWorkStatusFeedback: {
            /// Feedback: 识别过程反馈的打点数据 NSString
            NSDictionary *logDic = [self parseLogToDic:aObj];
            NSLog(@"%@",[NSString stringWithFormat:@"CALLBACK Feedback: %@\n", logDic]);
            break;
        }
        case EVoiceRecognitionClientWorkStatusRecorderEnd: {
            /// 录音机关闭，页面跳转需检测此时间，规避状态条 (iOS)
            NSLog(@"CALLBACK: recorder closed.\n");
            break;
        }
        case EVoiceRecognitionClientWorkStatusLongSpeechEnd: {
            /// 长语音结束状态
            NSLog(@"CALLBACK: Long Speech end.\n");
            [self endLongSpeechRecognition];
            break;
        }
        default:
            break;
    }
}

#pragma mark - AVAudioPlayerDelegate
-(void)audioPlayerDidFinishPlaying:(AVAudioPlayer *)player successfully:(BOOL)flag{
    if (flag) {
        if (self.delegate && [self.delegate respondsToSelector:@selector(recognitionRecordFinishedPlay)]) {
            [self.delegate recognitionRecordFinishedPlay];
        }
    }
}

#pragma mark - public: Method
-(void)didRemoveAudioPlayer:(BOOL)isNeedDeleteFilePath{

    [_audioPlayer  stop];
    [_progressLink invalidate];
    _audioPlayer = nil;
    _progressLink = nil;

    if (isNeedDeleteFilePath) {
        [[NSFileManager defaultManager] removeItemAtPath:_audioFilePath error:nil];
        _audioFilePath = nil;
    }
}

- (void)beginStatisticsReadingTime{
    [self.readingTimer fire];
}

- (void)endStatisticsReadingTime{
    if (self.readingTimer.isValid) {
        [self.readingTimer invalidate];
        self.readingTimer = nil;
    }
}

#pragma mark - private: Method

- (NSDictionary *)parseLogToDic:(NSString *)logString
{
    NSArray *tmp = NULL;
    NSMutableDictionary *logDic = [[NSMutableDictionary alloc] initWithCapacity:];
    NSArray *items = [logString componentsSeparatedByString:@"&"];
    for (NSString *item in items) {
        tmp = [item componentsSeparatedByString:@"="];
        if (tmp.count == ) {
            [logDic setObject:tmp.lastObject forKey:tmp.firstObject];
        }
    }
    return logDic;
}

- (NSString *)getDescriptionForDic:(NSDictionary *)dic {
    if (dic) {
        return [[NSString alloc] initWithData:[NSJSONSerialization dataWithJSONObject:dic
                                                                              options:NSJSONWritingPrettyPrinted
                                                                                error:nil]
                                     encoding:NSUTF8StringEncoding];
    }
    return nil;
}

#pragma mark - Private: File

- (NSString *)getFilePath:(NSString *)fileName {
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    if (paths && [paths count]) {
        return [[paths objectAtIndex:] stringByAppendingPathComponent:fileName];
    } else {
        return nil;
    }
}

- (void)configFileHandler:(NSString *)fileName {
    self.fileHandler = [self createFileHandleWithName:fileName isAppend:NO];
}

- (NSFileHandle *)createFileHandleWithName:(NSString *)aFileName isAppend:(BOOL)isAppend {

    NSFileHandle *fileHandle = nil;
    NSString *fileName = [self getFilePath:aFileName];

    int fd = -;
    if (fileName) {
        if ([[NSFileManager defaultManager] fileExistsAtPath:fileName]&& !isAppend) {
            [[NSFileManager defaultManager] removeItemAtPath:fileName error:nil];
        }

        int flags = O_WRONLY | O_APPEND | O_CREAT;
        fd = open([fileName fileSystemRepresentation], flags, );
    }

    if (fd != -) {
        fileHandle = [[NSFileHandle alloc] initWithFileDescriptor:fd closeOnDealloc:YES];
    }
    return fileHandle;
}

#pragma mark - lazy load
-(NSMutableData *)mutabelData{
    if (!_mutabelData) {
        _mutabelData = [NSMutableData data];
    }
    return _mutabelData;
}
-(NSTimer *)readingTimer{
    if (!_readingTimer) {
        _readingTimer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(startReadingTimer) userInfo:nil repeats:YES];
        [[NSRunLoop currentRunLoop] addTimer:_readingTimer forMode:UITrackingRunLoopMode];
    }
    return _readingTimer;
}

#endif

@end

四、注意

百度语音SDK只支持armv6、armv7的真机架构，不支持x86_64模拟器架构。

五、如何在模拟器下开发

办法：

1、首先将涉及到百度语音的代码全部采用宏定义注释掉，如：

#if !TARGET_IPHONE_SIMULATOR
// 语音相关调用
// self.asrEventManager = [BDSEventManager createEventManagerWithName:BDS_ASR_NAME];
// 其他调用
#endif

2、（重点要处理的地方）切换到模拟时，将libBaiduSpeechSDK.a静态包从Linked Frameworks and Librarise删掉(切换到真机时，再将libBaiduSpeechSDK.a导入进来就行)