objective-c - 视频捕获 1 :1 aspect ratio in iOS

Question

我想使用 1:1 宽高比的 iOS 相机拍摄视频。

我试过使用 UIImagePickerController，但它不提供改变纵横比的功能。谁能给我点意见？

此外，iPhone 应用程序“Viddy”提供 1:1 宽高比视频捕获:

Answer 1

AVCaptureVideoPreviewLayer *_preview = [AVVideoCaptureVideoPreviewLayer layerWithSession:_session];

_preview.frame = CGRectMake(0,0,320,320);
_preview.videoGravity = AVLayerVideoGravityResizeAspectFill;



NSDictionary *videoSettings = [NSDictionary dictionaryWithObjectsAndKeys:
                               AVVideoCodecH264, AVVideoCodecKey,
                               [NSNumber numberWithInt:320], AVVideoWidthKey,
                               [NSNumber numberWithInt:320], AVVideoHeightKey,
                               AVVideoScalingModeResizeAspectFill,AVVideoScalingModeKey,
                               nil];

self.videoInput = [AVAssetWriterInput assetWriterInputWithMediaType: AVMediaTypeVideo
                                                     outputSettings: videoSettings];


self.videoInput.transform = CGAffineTransformMakeRotation(M_PI);
if([_writer canAddInput:_videoInput]) // AVAssetWriter *_writer
    [_writer addInput:_videoInput];

注意:

_preview 的 videoGravity 和 videoSettings AVVideoScalingModeKey 应该相同以获得 320 x 320 的输出。