音视频的API选择

1.上层API

对于仅仅想直接播放个音频或视频的需求,没有必要使用底层的API,这些API可以简单的直接调用一些类似start,stop,设置一些资源文件路径就可以做录制与播放.

视频播放:AVPlayer

视频录制:UIImagePickerController

音频播放:AVAudioRecorder

音频录制:AVAudioPlayer

以上API如需了解使用自行百度,简单易用.

2.中层API

如果想采集到视频帧,音频帧加以利用,需要使用一些中层的API,对于采集而言,视频最底层即AVCaptureSession,我们可以通过回调函数拿到指定格式的音频视频.录制基本也同理.但对音频而言,如果不对音频有太多具体设置,仅仅做同步,可以直接使用AVCaputureSession中的音频采集.

音视频采集: AVCaptureSession

原理篇: 掘金, 简书,博客

实战篇: 掘金,简书,博客

音视频录制: AVAssetWriter,AVCaptureMovieFileOutput - 掘金, 简书,博客

3.底层,功能最多的API

音频采集方面还可以使用更底层,更好用的Audio Queue, Audio Unit.

音频采集/播放: Audio Queue, Audio Unit

音频录制: Audio File -简书,掘金,博客

Audio Queue与Audio Unit的选择

Audio Queue: 以队列的形式高效采集音频数据,可以直接设置采集PCM,AAC等压缩,未压缩类型格式音频数据.

原理篇:掘金,简书,博客

实战篇:简书,博客, 掘金

Audio Unit: 比起Audio Queue, 提供更加专业音频处理,支持混合,均衡,格式转换和实时输入/输出,用于录制,播放,离线渲染和实时对话,例如VoIP(互联网协议语音).可以从iOS应用程序动态加载和使用它.

原理篇:掘金,简书,博客

实战篇:掘金,简书,博客

AVAudioRecorder实现录制

AVAudioRecorder类是专门处理录音操作，可以在你的应用程序提供音频记录功能。录音只能保存到本地文件。它包含在AVFoundation FrameWork库中。

在创建录音机时除了指定路径外还必须指定录音设置信息，因为录音机必须知道录音文件的格式、采样率、通道数等信息。

通过xcode找到真机调试的沙盒路径文件

在这里插入图片描述

代码

////  ViewController.m//  录音////  Created by on 2020/2/25.//  Copyright © 2020 Shae. All rights reserved.//#import "ViewController.h"#import 
   
    @interface ViewController ()@property (nonatomic,strong)NSURL *url;@property (nonatomic,strong)AVAudioRecorder *recorder;@end@implementation ViewController- (NSURL *)url{
       if (_url==nil) {
           NSString *tmpDir=NSTemporaryDirectory();//获取沙盒的TemporaryDirectory路径        NSString *urlPath=[tmpDir stringByAppendingString:@"record.caf"];        _url=[NSURL fileURLWithPath:urlPath];        NSLog(@"_url:%@",_url);    }    return _url;}- (void)viewDidLoad {
       [super viewDidLoad];    // Do any additional setup after loading the view, typically from a nib.}- (IBAction)startRecord:(UIButton *)sender {
       NSLog(@"开始录音");    NSError *error=nil;//    //1.激活AVAudioSession    AVAudioSession *session=[AVAudioSession sharedInstance];//单例类    [session setCategory:AVAudioSessionCategoryPlayAndRecord error:&error];    if (session !=nil) {
           [session setActive:YES error:nil];    }else{
           NSLog(@"session error :%@",error);    }    //2.设置AVAudioSession类的属性    NSDictionary *recoderSettings=[[NSDictionary alloc]initWithObjectsAndKeys:[NSNumber numberWithFloat:16000.0],AVSampleRateKey,[NSNumber numberWithInt:kAudioFormatAppleIMA4],AVFormatIDKey,[NSNumber numberWithInt:1],AVNumberOfChannelsKey,[NSNumber numberWithInt:AVAudioQualityMax],AVEncoderAudioQualityKey, nil];//采样率，格式，Channel，采样质量    //3.初始化recod对象    self.recorder=[[AVAudioRecorder alloc]initWithURL:self.url settings:recoderSettings error:nil];    //4.开始录音    [self.recorder record];}- (IBAction)endRecord:(UIButton *)sender {
       NSLog(@"结束录音");    [self.recorder stop];    self.recorder=nil;//停止录音需要将现有AVAudioRecorder释放掉，不然再次录音会录到之前的文件里}@end

播放录音AVAudioPlayer

缺点：AVAudioPlayer不支持加载网络媒体流，只能播放本地文件

优点：能够精确控制播放进度、音量、播放速度等属性

(1) 初始化AVAudioPlayer对象，此时通常指定本地文件路径

(2) 设置播放器属性，例如重复次数、音量大小等

(3) 调用play方法播放

////  ViewController.m//  录音////  Created by 谢鑫 on 2020/2/25.//  Copyright © 2020 Shae. All rights reserved.//#import "ViewController.h"#import 
   
    @interface ViewController ()
    
     @property (nonatomic,strong)NSURL *url;@property (nonatomic,strong)AVAudioRecorder *recorder;@property (nonatomic,strong)AVAudioPlayer *player;@end@implementation ViewController- (NSURL *)url{
       if (_url==nil) {
           NSString *tmpDir=NSTemporaryDirectory();//获取沙盒的TemporaryDirectory路径        NSString *urlPath=[tmpDir stringByAppendingString:@"record.caf"];        _url=[NSURL fileURLWithPath:urlPath];        NSLog(@"_url:%@",_url);    }    return _url;}- (AVAudioPlayer *)player{
       if (_player==nil) {
           _player=[[AVAudioPlayer alloc] initWithContentsOfURL:self.url error:nil];        _player.volume=1.0;        _player.delegate=self;    }    return _player;}- (void)viewDidLoad {
       [super viewDidLoad];    // Do any additional setup after loading the view, typically from a nib.}- (IBAction)startRecord:(UIButton *)sender {
       NSLog(@"开始录音");    NSError *error=nil;//    //1.激活AVAudioSession    AVAudioSession *session=[AVAudioSession sharedInstance];//单例类    [session setCategory:AVAudioSessionCategoryPlayAndRecord error:&error];    if (session !=nil) {
           [session setActive:YES error:nil];    }else{
           NSLog(@"session error :%@",error);    }    //2.设置AVAudioSession类的属性    NSDictionary *recoderSettings=[[NSDictionary alloc]initWithObjectsAndKeys:[NSNumber numberWithFloat:16000.0],AVSampleRateKey,[NSNumber numberWithInt:kAudioFormatAppleIMA4],AVFormatIDKey,[NSNumber numberWithInt:1],AVNumberOfChannelsKey,[NSNumber numberWithInt:AVAudioQualityMax],AVEncoderAudioQualityKey, nil];//采样率，格式，Channel，采样质量    //3.初始化recod对象    self.recorder=[[AVAudioRecorder alloc]initWithURL:self.url settings:recoderSettings error:nil];    //4.开始录音    [self.recorder record];}- (IBAction)endRecord:(UIButton *)sender {
       NSLog(@"结束录音");    [self.recorder stop];    self.recorder=nil;//停止录音需要将现有AVAudioRecorder释放掉，不然再次录音会录到之前的文件里}- (IBAction)playRecord:(UIButton *)sender {
           [self.player play];}#pragma AVAudioPlayer的代理方法- (void)audioPlayerDidFinishPlaying:(AVAudioPlayer *)player successfully:(BOOL)flag{
       NSLog(@"%s",__func__);    self.player=nil;}@end

如果自定义播放器可参考：https://blog.csdn.net/qq_18505715/article/details/79868677

微信录音实现（长按录音）

微信录音是长按录音，所以要用到长按手势。

UILongPressGestureRecognizer *longPress=[[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPressToRecord:)];    [_longPressBtn addGestureRecognizer:longPress];

# pragma  mark --自定义方法-(void)longPressToRecord:(UILongPressGestureRecognizer *)gesture{
       if(gesture.state==UIGestureRecognizerStateBegan){
           //开始录音        [self startRecord];    }else{
           //结束录音        [self endRecord];    }    }

音频播放

NSSlider控制音量

////  ViewController.m//  播放音频////  Created by 谢鑫 on 2020/2/25.//  Copyright © 2020 Shae. All rights reserved.//#import "ViewController.h"#import 
   
    @interface ViewController ()@property (nonatomic,strong)AVAudioPlayer *player;@end@implementation ViewController- (void)viewDidLoad {
       [super viewDidLoad];    // Do any additional setup after loading the view, typically from a nib.}- (AVAudioPlayer *)player{
       NSString *urlString=[[NSBundle mainBundle]pathForResource:@"bg" ofType:@"mp3"];    NSURL *url=[NSURL fileURLWithPath:urlString];    if (_player==nil) {
           _player=[[AVAudioPlayer alloc]initWithContentsOfURL:url error:nil];    }    return _player;}- (IBAction)play:(UIButton *)sender {
       [self.player play];}- (IBAction)pause:(UIButton *)sender {
       [self.player pause];}- (IBAction)stop:(UIButton *)sender {
       [self.player stop];    self.player=nil;}- (IBAction)valueChange:(UISlider *)sender {
       self.player.volume=sender.value;}@end