AVCaptureVideoPreviewLayer: using with Storyboard and Autolayout - ios

Question

I have a UIView on my Storyboard with four simple constraints set the fill the entire screen - my application is for landscape use only. This UIView is to show the camera's live preview, utilizing AVCaptureVideoPreviewLayer.
I have tried using some code examples found on StackOverflow and the wider internet, initiating an AVCaptureSession and AVCaptureVideoPreviewLayer; however, none have successfully functioned. The UIView on the storyboard always ends up failing to display on screen (white screen when view loads)
I wish to create my app's entire interface with the interface builder using constraints, yet reap the functionality of AVCaptureVideoPreviewLayer. Can someone provide a full code example to assist me if they have a possible solution?

Answer 1

This is my code, it works for me. The head file AVCameraCaptureData.h:
#interface AVCameraCaptureData : NSObject
#property (nonatomic, strong) AVCaptureSession *captureSession;
#property (nonatomic, strong) AVCaptureConnection *captureConnection;
#property (nonatomic, strong) AVCaptureDeviceInput *deviceInput;
#property (nonatomic, strong) AVCaptureStillImageOutput *captureOutput;
#property (nonatomic, strong) AVCaptureVideoPreviewLayer *previewLayer;
#end
#if defined(__cplusplus)
extern "C"
{
#endif /* defined(__cplusplus) */
AVCaptureDevice* getCaptureDeviceByPosition(AVCaptureDevicePosition position);
AVCaptureStillImageOutput* getCaptureOutput();
AVCaptureConnection* ConnectionWithMediaType (NSString* mediaType, NSArray* fromConnections);
AVCaptureVideoPreviewLayer* getCapturePreviewLayer(AVCaptureSession* captureSession);
AVCameraCaptureData* CreateCaptureData (AVCaptureDevicePosition position, CGRect presentLayerFrame, NSString* sessionPreset);
#if defined(__cplusplus)
}
#endif /* defined(__cplusplus) */
AVCameraCaptureData.m file:
#import "AVCameraCaptureData.h"
#import "AVCameraUtil.h"
#implementation AVCameraCaptureData
AVCaptureDevice* getCaptureDeviceByPosition(AVCaptureDevicePosition position)
{
NSArray *devices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
for (AVCaptureDevice *device in devices)
{
if ([device position] == position)
return device;
}
return nil;
}
AVCaptureStillImageOutput* getCaptureOutput()
{
AVCaptureStillImageOutput* captureOutput = [[AVCaptureStillImageOutput alloc] init];
NSDictionary* outputSettings = [[NSDictionary alloc] initWithObjectsAndKeys:AVVideoCodecJPEG, AVVideoCodecKey, nil];
[captureOutput setOutputSettings:outputSettings];
return captureOutput;
}
AVCaptureConnection* ConnectionWithMediaType (NSString* mediaType, NSArray* fromConnections)
{
for (AVCaptureConnection* connection in fromConnections)
{
for (AVCaptureInputPort* port in [connection inputPorts])
{
if ([[port mediaType] isEqual:mediaType])
return connection;
}
}
return nil;
}
AVCaptureVideoPreviewLayer* getCapturePreviewLayer(AVCaptureSession* captureSession)
{
AVCaptureVideoPreviewLayer* previewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:captureSession];
//please set frame for yourself
[previewLayer setFrame:[AVCameraUtil screenBoundsFixedToPortraitOrientation]];
previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
return previewLayer;
}
AVCameraCaptureData* CreateCaptureData (AVCaptureDevicePosition position, CGRect presentLayerFrame, NSString* sessionPreset)
{
AVCaptureSession* captureSession = [[AVCaptureSession alloc] init];
if (sessionPreset == nil)
[captureSession setSessionPreset:AVCaptureSessionPresetPhoto];
else
[captureSession setSessionPreset:sessionPreset];
AVCaptureDevice *device = getCaptureDeviceByPosition (position);
AVCaptureDeviceInput *videoDeviceInput = [[AVCaptureDeviceInput alloc] initWithDevice:device error:nil];
if ([captureSession canAddInput:videoDeviceInput])
[captureSession addInput:videoDeviceInput];
AVCaptureStillImageOutput* captureOutput = getCaptureOutput();
if ([captureSession canAddOutput:captureOutput])
[captureSession addOutput:captureOutput];
AVCameraCaptureData *data = [[AVCameraCaptureData alloc] init];
data.captureSession = captureSession;
data.deviceInput = videoDeviceInput;
data.captureOutput = captureOutput;
data.captureConnection = ConnectionWithMediaType(AVMediaTypeVideo, [captureOutput connections]);
data.previewLayer = getCapturePreviewLayer(captureSession);
return data;
}
#end
Then you can init AVCameraCaptureData with function in your controller
CreateCaptureData(AVCaptureDevicePositionBack, self.view.frame,nil);
Start run session:
[self.captureData.captureSession startRunning];
Add AVCaptureVideoPreviewLayer to view.layer:
[self.view.layer addSublayer:self.captureData.previewLayer];