推广

iOS 自定义相机拍照+视频录制(二)

iseeyu3年前 (2024-02-21)推广132

shortrecord.gif

框架：<AVFoundation/AVFoundation.h>

关键类： AVAssetWriter

大致需要属性

@property (nonatomic ,strong) AVAssetWriter *writer;//视频采集
@property (nonatomic ,strong) AVAssetWriterInput *writerAudioInput;//视频采集
@property (nonatomic ,strong) AVAssetWriterInput *writerVideoInput;//视频采集

大致流程：

session 初始化
device 初始化
input，output 初始化，并关联device
session 添加 input 和 output
初始化预览层 AVCaptureVideoPreviewLayer
session startRunning
点击录制按钮, 录制视频代理回调后，处理数据，写入文件，生成视频

PS : 和拍照的区别点在于，首先，需要使用不同的 input 和 output ,视频拍摄还需要音频的输入输出设备，其次，回调的代理是不一样的，并且只要我们 session 执行了 startRunning 回调就会一直进行，所以需要一个额外的变量来控制什么时候开始真正的写入视频数据

视频的输入输出初始化

#pragma mark 设置视频类型的输入输出源
-(void)addVideoIO{

    //视频输出源
    NSDictionary *videoSetting = @{(id)kCVPixelBufferPixelFormatTypeKey:@(kCVPixelFormatType_32BGRA)};

    self.videoPutData = [[AVCaptureVideoDataOutput alloc]init];
    self.videoPutData.videoSettings = videoSetting;

    dispatch_queue_t videoQueue = dispatch_queue_create("vidio", DISPATCH_QUEUE_CONCURRENT);
    [self.videoPutData setSampleBufferDelegate:self queue:videoQueue];

    if ([self.session canAddOutput:self.videoPutData]) {
        [self.session addOutput:self.videoPutData];
    }


    //音频输入源
    AVCaptureDevice *audioDevice = [[AVCaptureDevice devicesWithMediaType:AVMediaTypeAudio]firstObject];
    NSError *audioError = nil;
    self.audioInput = [[AVCaptureDeviceInput alloc]initWithDevice:audioDevice error:&audioError];
    if (!audioError) {
        if ([self.session canAddInput:self.audioInput]) {
            [self.session addInput:self.audioInput];
        }
    }

    //音频输出源
    self.audioPutData = [[AVCaptureAudioDataOutput alloc]init];
    if ([self.session canAddOutput:self.audioPutData]) {
        [self.session addOutput:self.audioPutData];
    }

    dispatch_queue_t audioQueue = dispatch_queue_create("audio", DISPATCH_QUEUE_CONCURRENT);
    [self.audioPutData setSampleBufferDelegate:self queue:audioQueue];
}

点击拍摄即初始化 writer

// 配置 AVAssetWriter
-(void)configWriter{

    dispatch_queue_t writeQueueCreate = dispatch_queue_create("writeQueueCreate", DISPATCH_QUEUE_CONCURRENT);

    dispatch_async(writeQueueCreate, ^{

        NSError *error = nil;
        self.preVideoURL = [self getVideoURL];

        self.writer = [AVAssetWriter assetWriterWithURL:self.preVideoURL fileType:AVFileTypeMPEG4 error:&error];

        if (!error) {

            NSInteger numPixels = SCREEN_WIDTH * SCREEN_HEIGHT;
            //每像素比特
            CGFloat bitsPerPixel = 12.0;
            NSInteger bitsPerSecond = numPixels * bitsPerPixel;

            // 码率和帧率设置
            NSDictionary *compressionProperties = @{ AVVideoAverageBitRateKey : @(bitsPerSecond),
                                                     AVVideoExpectedSourceFrameRateKey : @(15),
                                                     AVVideoMaxKeyFrameIntervalKey : @(10),
                                                     AVVideoProfileLevelKey : AVVideoProfileLevelH264BaselineAutoLevel };

            //视频属性
            NSDictionary *videoSetting = @{ AVVideoCodecKey : AVVideoCodecH264,
                                            AVVideoWidthKey : @(SCREEN_HEIGHT * 2),
                                            AVVideoHeightKey : @(SCREEN_WIDTH * 2),
                                            AVVideoScalingModeKey : AVVideoScalingModeResizeAspectFill,
                                            AVVideoCompressionPropertiesKey : compressionProperties };

            NSDictionary *audioSetting = @{ AVEncoderBitRatePerChannelKey : @(28000),
                                            AVFormatIDKey : @(kAudioFormatMPEG4AAC),
                                            AVNumberOfChannelsKey : @(1),
                                            AVSampleRateKey : @(22050) };

            self.writerAudioInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeAudio outputSettings:audioSetting];
            self.writerAudioInput.expectsMediaDataInRealTime = YES;

            self.writerVideoInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeVideo outputSettings:videoSetting];
            self.writerVideoInput.expectsMediaDataInRealTime = YES;

            self.writerVideoInput.transform = CGAffineTransformMakeRotation(M_PI/2.0);

            if ([self.writer canAddInput:self.writerAudioInput]) {
                [self.writer addInput:self.writerAudioInput];
            }

            if ([self.writer canAddInput:self.writerVideoInput]) {
                [self.writer addInput:self.writerVideoInput];
            }

            self.videoRecording = YES;

        }else{
            NSLog(@"write 初始化失败：%@",error);
        }

    });
}

处理回调

//视频录制回调
-(void)captureOutput:(AVCaptureOutput *)output didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection{

    if (!self.videoRecording) {
        return;
    }

    CMFormatDescriptionRef desMedia = CMSampleBufferGetFormatDescription(sampleBuffer);
    CMMediaType mediaType = CMFormatDescriptionGetMediaType(desMedia);

    if (mediaType == kCMMediaType_Video) {
        
        /**
         * 要点1：
         * 由于 self.canWritting = YES 放在 startSessionAtSourceTime
         * 下，会出现录制的视频 前几帧相同(可能2-3帧都是第一帧) 的问题，故而将
         * self.canWritting = YES 放在 startsession 上，目前测试没出现问题
         */
        
        /**
         * 要点2：
         * 对于 startSessionAtSourceTime 开启时机需要放在类型为
         * kCMMediaType_Video 里判断，因为如果放在外边，可能会导致录制的时候
         * 是没有画面的，但是有声音，这就导致了预览视频的时候发现开头有一段空白视频
         * 但是是有声音的
         */
        
        /**
         * 要点3：
         * 需要将 startSessionAtSourceTime 方法放在类型为kCMMediaType_Video里
         * 确保第一帧为图像在开启录制
         */
        
        if (!self.canWritting) {
            [self.writer startWriting];

            CMTime timestamp = CMSampleBufferGetPresentationTimeStamp(sampleBuffer);

            self.canWritting = YES;
            [self.writer startSessionAtSourceTime:timestamp];
        }
    }
    
    
    if (self.canWritting) {
        
        if (mediaType == kCMMediaType_Video) {
            if (self.writerVideoInput.readyForMoreMediaData ) {
                
                BOOL success = [self.writerVideoInput appendSampleBuffer:sampleBuffer];
                if (!success) {
                    NSLog(@"video write failed");
                }
            }
            
        }else if (mediaType == kCMMediaType_Audio && self.canWritting){
            
            if (self.writerAudioInput.readyForMoreMediaData) {
                BOOL success = [self.writerAudioInput appendSampleBuffer:sampleBuffer];
                if (!success) {
                    NSLog(@"audio write failed");
                }
            }
        }
    }
}

PS：处理视频回调有几个需要注意的点，都在代码的注释上写好了

视频预览

// 视频录制完成后 预览
-(void)previewVideo{

    if (self.playerLayer) {
        [self.playerLayer removeFromSuperlayer];
        self.player = nil;
        self.playerLayer = nil;
    }

    AVPlayerItem *playerItem = [AVPlayerItem playerItemWithAsset:[AVAsset assetWithURL:self.preVideoURL]];
    self.player = [[AVPlayer alloc]initWithPlayerItem:playerItem];

    self.playerLayer = [AVPlayerLayer playerLayerWithPlayer:self.player];
    self.playerLayer.videoGravity = AVLayerVideoGravityResizeAspect;
    self.playerLayer.frame = self.view.frame;

    [self.view.layer addSublayer:self.playerLayer];
    [self.player play];
    
    [self.view bringSubviewToFront:self.bottomView];

}

存储视频

//videoPath为视频下载到本地之后的本地路径
- (void)saveVideoToAlbum:(NSString*)videoPath{

    if(videoPath) {

        BOOL compatible = UIVideoAtPathIsCompatibleWithSavedPhotosAlbum(videoPath);

        if(compatible){
            UISaveVideoAtPathToSavedPhotosAlbum(videoPath,self,@selector(video:didFinishSavingWithError:contextInfo:),nil);
        }
    }
}

//保存视频完成之后的回调
- (void)video:(NSString *)videoPath didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo{

    if(error) {
        NSLog(@"保存视频失败%@", error);
    }else{
        // 保存视频成功后退出，刷新相册，退出界面
        if ([self.delegate respondsToSelector:@selector(photoCameraNextBtnClickedWithVideoPath:)]) {
            [self.delegate photoCameraNextBtnClickedWithVideoPath:videoPath];
        }
        [[NSNotificationCenter defaultCenter]postNotificationName:@"didFinishSelectVideo" object:videoPath];
        [self.navigationController dismissViewControllerAnimated:YES completion:nil];
    }
}

友情链接

GitHub 项目地址
iOS 自定义相机拍照+视频录制(一) 拍照篇

扫描二维码推送至手机访问。

转载请注明出处https://www.0291.com.cn/post/57405.html

返回列表

上一篇：Vue3.0和2.0的区别

下一篇：Vue面试题

西安企业做百度推广，一个月花三千和花三万到底差在哪？

4|最近跟几个西安的老板聊天，发现一个挺有意思的现象：同样做百度推广，有人一个月花三千块，询盘不断；有人一个月砸三万，水花都没见着。问他们区别在哪，大多数人说不清楚，只知道'钱花了，没效果'。 5| 6|百度推广这东西，说复杂也复杂，说简单也简单。核心就一件事：让你的潜在客户搜某个词的时候，你的信息...