iOS 视频录制

1,视频录制需要添加几个方法
//后置摄像头输入

- (AVCaptureDeviceInput *)backCameraInput {
    if (_backCameraInput == nil) {
        NSError *error;
        _backCameraInput = [[AVCaptureDeviceInput alloc] initWithDevice:[self backCamera] error:&error];
        if (error) {
            NSLog(@"获取后置摄像头失败~");
        }
    }
    return _backCameraInput;
}

前置摄像头输入

- (AVCaptureDeviceInput *)frontCameraInput {
    if (_frontCameraInput == nil) {
        NSError *error;
        _frontCameraInput = [[AVCaptureDeviceInput alloc] initWithDevice:[self frontCamera] error:&error];
        if (error) {
            NSLog(@"获取前置摄像头失败~");
        }
    }
    return _frontCameraInput;
}

麦克风输入

- (AVCaptureDeviceInput *)audioMicInput {
    if (_audioMicInput == nil) {
        AVCaptureDevice *mic = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeAudio];
        NSError *error;
        _audioMicInput = [AVCaptureDeviceInput deviceInputWithDevice:mic error:&error];
        if (error) {
            NSLog(@"获取麦克风失败~");
        }
    }
    return _audioMicInput;
}

视频输出

- (AVCaptureVideoDataOutput *)videoOutput {
    if (_videoOutput == nil) {
        _videoOutput = [[AVCaptureVideoDataOutput alloc] init];
        [_videoOutput setSampleBufferDelegate:self queue:self.captureQueue];
        NSDictionary* setcapSettings = [NSDictionary dictionaryWithObjectsAndKeys:
                                        [NSNumber numberWithInt:kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange], kCVPixelBufferPixelFormatTypeKey,
                                        nil];
        _videoOutput.videoSettings = setcapSettings;
    }
    return _videoOutput;
}

音频输出

- (AVCaptureAudioDataOutput *)audioOutput {
    if (_audioOutput == nil) {
        _audioOutput = [[AVCaptureAudioDataOutput alloc] init];
        [_audioOutput setSampleBufferDelegate:self queue:self.captureQueue];
    }
    return _audioOutput;
}

捕获到的视频呈现的layer

- (AVCaptureVideoPreviewLayer *)previewLayer {
    if (_previewLayer == nil) {
        //通过AVCaptureSession初始化
        AVCaptureVideoPreviewLayer *preview = [[AVCaptureVideoPreviewLayer alloc] initWithSession:self.recordSession];
        //设置比例为铺满全屏
        preview.videoGravity = AVLayerVideoGravityResizeAspectFill;
        _previewLayer = preview;
    }
    return _previewLayer;
}

2,将mov文件转为MP4文件

- (void)changeMovToMp4:(NSURL *)mediaURL dataBlock:(void (^)(UIImage *movieImage))handler {
    AVAsset *video = [AVAsset assetWithURL:mediaURL];
    AVAssetExportSession *exportSession = [AVAssetExportSession exportSessionWithAsset:video presetName:AVAssetExportPreset1280x720];
    exportSession.shouldOptimizeForNetworkUse = YES;
    exportSession.outputFileType = AVFileTypeMPEG4;
    NSString * basePath=[self getVideoCachePath];
    
    self.videoPath = [basePath stringByAppendingPathComponent:[self getUploadFile_type:@"video" fileType:@"mp4"]];
    exportSession.outputURL = [NSURL fileURLWithPath:self.videoPath];
    [exportSession exportAsynchronouslyWithCompletionHandler:^{
        [self movieToImageHandler:handler];
    }];
}

3,下面说一下参数的调节当然也不一定非常准确希望指点改正
初始化视频输入

- (void)initVideoInputHeight:(NSInteger)cy width:(NSInteger)cx {
    //录制视频的一些配置，分辨率，编码方式等等
    NSDictionary* settings = [NSDictionary dictionaryWithObjectsAndKeys:
                              AVVideoCodecH264, AVVideoCodecKey,
                              [NSNumber numberWithInteger: cx], AVVideoWidthKey,
                              [NSNumber numberWithInteger: cy], AVVideoHeightKey,
                              nil];
    //初始化视频写入类
    _videoInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeVideo outputSettings:settings];
    //表明输入是否应该调整其处理为实时数据源的数据
    _videoInput.expectsMediaDataInRealTime = YES;
    //将视频输入源加入
    [_writer addInput:_videoInput];
}

初始化音频输入

- (void)initAudioInputChannels:(int)ch samples:(Float64)rate {
    //音频的一些配置包括音频各种这里为AAC,音频通道、采样率和音频的比特率
    NSDictionary *settings = [NSDictionary dictionaryWithObjectsAndKeys:
                              [ NSNumber numberWithInt: kAudioFormatMPEG4AAC], AVFormatIDKey,
                              [ NSNumber numberWithInt: ch], AVNumberOfChannelsKey,
                              [ NSNumber numberWithFloat: rate], AVSampleRateKey,
                              [ NSNumber numberWithInt: 128000], AVEncoderBitRateKey,
                              nil];
    //初始化音频写入类
    _audioInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeAudio outputSettings:settings];
    //表明输入是否应该调整其处理为实时数据源的数据
    _audioInput.expectsMediaDataInRealTime = YES;
    //将音频输入源加入
    [_writer addInput:_audioInput];
    
}

源码我传到了 git 上!奉上 git 网址
https://github.com/W-King/PPX_VideoRecording.git