iOS中实现语音转文字，除了一些第三方，如科大讯飞语音、百度语音等第三方的外(这种第三方的在其官方都有详细的教程，这里就不在叙述了。特点是：百度语音支持离线并免费。讯飞的也支持离线，虽然识别率很高也很精准，但是收费)，苹果官方也推出了自己的一套识别标准。
苹果官方的文字转语音支持iOS10之后
文字转语音的需求：
1.创建一个按钮用来控制启动、关闭录音
2.创建一个语音控制器，一个语音识别器 。一个语音任务管理器，
3.创建显示转换好的文字的控件
步骤：
iOS语音转文字：1.需要添加Speech.framework库 2.导入头文件#import
3.在info.plist文件里添加了两个键值Privacy - Microphone Usage Description、Privacy - Speech Recognition Usage Description
具体代码如下：
#import "ViewController.h"
#import<Speech/Speech.h>
#import<AVFoundation/AVFoundation.h>
@interface ViewController ()
@property (nonatomic,strong)UIButton *swicthBut;
@property (nonatomic,strong)UILabel *labText;
@property(nonatomic,strong)SFSpeechRecognizer*speechRecognizer;//语音识别器
@property (nonatomic,strong) SFSpeechAudioBufferRecognitionRequest *recognitionRequest;//语音识别请求
@property (nonatomic, strong) SFSpeechRecognitionTask *recognitionTask;//语音任务管理器
@property (nonatomic,strong) AVAudioEngine *audioEngine;//语音控制器
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
//发送语音认证请求(首先要判断设备是否支持语音识别功能)
[SFSpeechRecognizer requestAuthorization:^(SFSpeechRecognizerAuthorizationStatus status) {
boolisButtonEnabled =false;
switch(status) {
case SFSpeechRecognizerAuthorizationStatusAuthorized:
isButtonEnabled =true;
NSLog(@"可以语音识别");
break;
case SFSpeechRecognizerAuthorizationStatusDenied:
isButtonEnabled =false;
NSLog(@"用户未授权使用语音识别");
break;
case SFSpeechRecognizerAuthorizationStatusRestricted:
isButtonEnabled =false;
NSLog(@"语音识别在这台设备上受到限制");
break;
case SFSpeechRecognizerAuthorizationStatusNotDetermined:
isButtonEnabled =false;
NSLog(@"语音识别未授权");
break;
default:
break;
}
}];
// Do any additional setup after loading the view, typically from a nib.
self.title=@"测试";
self.view.backgroundColor = [UIColor whiteColor];
[self.viewaddSubview:self.swicthBut];
[self.viewaddSubview:self.labText];
}
- (void)speechRecognizer:(SFSpeechRecognizer*)speechRecognizer availabilityDidChange:(BOOL)available{
if(available) {
self.swicthBut.enabled=YES;
[self.swicthBut setTitle:@"开始录音" forState:UIControlStateNormal];
}else{
self.swicthBut.enabled=NO;
[self.swicthBut setTitle:@"语音识别不可用" forState:UIControlStateNormal];
}
}
#pragma mark----语音识别
- (SFSpeechRecognizer*)speechRecognizer{
if (!_speechRecognizer) {
NSLocale *cale = [[NSLocale alloc]initWithLocaleIdentifier:@"zh-CN"];
_speechRecognizer= [[SFSpeechRecognizeralloc]initWithLocale:cale];
//设置代理
_speechRecognizer.delegate = self;
}
return _speechRecognizer;
}
#pragma mark---停止录音
- (void)endRecording{
[self.audioEngine stop];
if (_recognitionRequest) {
[_recognitionRequest endAudio];
}
if (_recognitionTask) {
[_recognitionTask cancel];
_recognitionTask = nil;
}
self.swicthBut.enabled=NO;
}
#pragma mark---开始录音
- (void)startRecording{
if (self.recognitionTask) {
[self.recognitionTask cancel];
self.recognitionTask = nil;
}
AVAudioSession *audioSession = [AVAudioSession sharedInstance];
NSError*error;
bool audioBool = [audioSessionsetCategory:AVAudioSessionCategoryRecorderror:&error];
NSParameterAssert(!error);
bool audioBool1= [audioSessionsetMode:AVAudioSessionModeMeasurementerror:&error];
NSParameterAssert(!error);
bool audioBool2= [audioSessionsetActive:true withOptions:AVAudioSessionSetActiveOptionNotifyOthersOnDeactivation error:&error];
NSParameterAssert(!error);
if(audioBool || audioBool1|| audioBool2) {
NSLog(@"可以使用");
}else{
NSLog(@"这里说明有的功能不支持");
}
self.recognitionRequest = [[SFSpeechAudioBufferRecognitionRequest alloc]init];
AVAudioInputNode *inputNode = self.audioEngine.inputNode;
NSAssert(inputNode,@"录入设备没有准备好");
NSAssert(self.recognitionRequest, @"请求初始化失败");
self.recognitionRequest.shouldReportPartialResults = true;
__weaktypeof(self) weakSelf =self;
//开始识别任务
self.recognitionTask = [self.speechRecognizer recognitionTaskWithRequest:self.recognitionRequest resultHandler:^(SFSpeechRecognitionResult * _Nullable result, NSError * _Nullable error) {
__strongtypeof(weakSelf) strongSelf = weakSelf;
boolisFinal =false;
if(result) {
strongSelf.labText.text= [[resultbestTranscription]formattedString];//语音转文本
isFinal = [resultisFinal];
}
if(error || isFinal) {
[strongSelf.audioEnginestop];
[inputNoderemoveTapOnBus:0];
strongSelf.recognitionRequest=nil;
strongSelf.recognitionTask=nil;
[strongSelf.swicthButsetTitle:@"开始录音"forState:UIControlStateNormal];
strongSelf.swicthBut.enabled=true;
}
}];
AVAudioFormat*recordingFormat = [inputNodeoutputFormatForBus:0];
//在添加tap之前先移除上一个 不然有可能报"Terminating app due to uncaught exception 'com.apple.coreaudio.avfaudio',"之类的错误
[inputNoderemoveTapOnBus:0];
[inputNodeinstallTapOnBus:0bufferSize:1024format:recordingFormatblock:^(AVAudioPCMBuffer*_Nonnullbuffer,AVAudioTime*_Nonnullwhen) {
__strongtypeof(weakSelf) strongSelf = weakSelf;
if(strongSelf.recognitionRequest) {
[strongSelf.recognitionRequestappendAudioPCMBuffer:buffer];
}
}];
[self.audioEngine prepare];
boolaudioEngineBool = [self.audioEnginestartAndReturnError:&error];
NSParameterAssert(!error);
self.labText.text = @"正在录音。。。";
NSLog(@"%d",audioEngineBool);
}
#pragma mark---创建录音引擎
- (AVAudioEngine*)audioEngine{
if (!_audioEngine) {
_audioEngine= [[AVAudioEnginealloc]init];
}
return _audioEngine;
}
#pragma mark----显示控件
- (UILabel*)labText{
if(!_labText) {
_labText= [[UILabelalloc]init];
_labText.frame = CGRectMake(0, 140, [UIScreen mainScreen].bounds.size.width, 50);
_labText.font= [UIFontsystemFontOfSize:13.0f];
_labText.numberOfLines = 0;
_labText.textAlignment = NSTextAlignmentCenter;
_labText.textColor = [UIColor yellowColor];
}
return _labText;
}
#pragma mark----开关
- (UIButton*)swicthBut{
if (!_swicthBut) {
_swicthBut= [[UIButtonalloc]init];
_swicthBut.frame=CGRectMake(50,100,80,30);
_swicthBut.titleLabel.textAlignment = NSTextAlignmentCenter;
[_swicthBut setTitleColor:[UIColor orangeColor] forState:UIControlStateNormal];
[_swicthBut addTarget:self action:@selector(switchOn:) forControlEvents:UIControlEventTouchUpInside];
[_swicthBut setTitle:@"开始录音" forState:UIControlStateNormal];
}
return _swicthBut;
}
- (void)switchOn:(id)sender{
if([self.audioEngineisRunning]) {
[self endRecording];
[_swicthBut setTitle:@"开始录音" forState:UIControlStateNormal];
}else{
[self startRecording];
[_swicthBut setTitle:@"关闭" forState:UIControlStateNormal];
}
}
#pragma mark---识别本地音频文件
- (void)recognizeLocalAudioFile:(UIButton*)sender {
NSLocale *local =[[NSLocale alloc] initWithLocaleIdentifier:@"zh_CN"];
SFSpeechRecognizer *localRecognizer =[[SFSpeechRecognizer alloc] initWithLocale:local];
NSURL *url =[[NSBundle mainBundle] URLForResource:@"录音.m4a" withExtension:nil];
if(!url)return;
SFSpeechURLRecognitionRequest *res =[[SFSpeechURLRecognitionRequest alloc] initWithURL:url];
__weak typeof(self) weakSelf = self;
[localRecognizerrecognitionTaskWithRequest:resresultHandler:^(SFSpeechRecognitionResult*_Nullableresult,NSError*_Nullableerror) {
if(error) {
NSLog(@"语音识别解析失败,%@",error);
}
else
{
weakSelf.labText.text = result.bestTranscription.formattedString;
}
}];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
@end
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