AVFoundation question

[Esko2300]

New problem scroll down 4 posts

CameraSessionManager.h

#import <Foundation/Foundation.h>
#import <QuartzCore/QuartzCore.h>
#import <CoreVideo/CoreVideo.h>
#import <AVFoundation/AVFoundation.h>
#import <QuartzCore/QuartzCore.h>

@interface CameraSessionManager : NSObject {
@private
    AVCaptureSession *captureSession;
    AVCaptureVideoPreviewLayer *previewLayer;
}
- (id)init;
- (void)addVideoInput;
- (void)addPreviewLayer;
@property (nonatomic,retain) AVCaptureSession *captureSession;
@property (nonatomic,retain) AVCaptureVideoPreviewLayer *previewLayer;
@end

;

CameraSessionManager.m

#import "CameraSessionManager.h"


@implementation CameraSessionManager
@synthesize captureSession,previewLayer;
- (id)init{
    self = [super init];
    if(self){
        [self addVideoInput];
        [self addPreviewLayer];
    }
    return self;
}

//GOAL:Sets up the videos input
- (void)addVideoInput{
    self.captureSession = [[AVCaptureSession alloc]init];//initialize capture session
    [self.captureSession setSessionPreset:AVCaptureSessionPresetMedium];
    
    AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];//set up a capture device with Media Type Video
    if(device){
        NSError *error;
        AVCaptureDeviceInput *videoIn = [AVCaptureDeviceInput deviceInputWithDevice:device error:&error];
        
        if(!error){
            if([self.captureSession canAddInput:videoIn])
                [self.captureSession addInput:videoIn];
            else
                NSLog(@"Cannot add video input");
        }
        else
            NSLog(@"Couldent create video input");
    }
    else
        NSLog(@"Couldent create video capture device");
    [self.captureSession release];    
}
//GOAL:Sets up the preview layer
- (void)addPreviewLayer{
    self.previewLayer = [[AVCaptureVideoPreviewLayer alloc]initWithSession:self.captureSession];//initialize the preview with the capture session
    [self.previewLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill];//set the previews layer view size in refernce to its frame
    [self.previewLayer release];    
}
- (void)dealloc{
    [self.captureSession stopRunning];
    [self.captureSession release];
    [self.previewLayer release];
    [super dealloc];
}

CameraCaptureManager.h

#import <Foundation/Foundation.h>
#import "CameraSessionManager.h"

@interface CameraCaptureManager : CameraSessionManager<AVCaptureVideoDataOutputSampleBufferDelegate> {
@private
    UIImage *frame; 
    AVCaptureStillImageOutput *captureStillImageOutput;
    AVCaptureVideoDataOutput *captureVideoOutput;
}
- (id)init;
- (void)addVideoOutput;
- (void)addStillImageOutput;
- (void)captureImage;
- (UIImage*)returnFrame;
- (void)imageFromSampleBuffer:(CMSampleBufferRef)sampleBuffer;
@property (nonatomic,retain) UIImage *frame;
@property (nonatomic,retain) AVCaptureStillImageOutput *captureStillImageOutput;
@property (nonatomic,retain) AVCaptureVideoDataOutput *captureVideoOutput;
@end

CameraCaptureManager.m

#import "CameraCaptureManager.h"


@implementation CameraCaptureManager
@synthesize frame;
@synthesize captureStillImageOutput,captureVideoOutput;

#pragma mark - Inilitializer
- (id)init{
    self = [super init];
    if(self){
        self.frame = [[UIImage alloc]init];
        [self addVideoOutput];
        [self addStillImageOutput];
    }
    return self;
}

#pragma mark - Setup output
//GOAL:Sets up the videos output
- (void)addVideoOutput{
    
    self.captureVideoOutput = [[AVCaptureVideoDataOutput alloc]init];//initialize video output
    self.captureVideoOutput.videoSettings = [NSDictionary dictionaryWithObject:[NSNumber numberWithInt:kCVPixelFormatType_32BGRA] forKey:(NSString*)kCVPixelBufferPixelFormatTypeKey];
    
    [self.captureVideoOutput setAlwaysDiscardsLateVideoFrames:TRUE];
    self.captureVideoOutput.minFrameDuration = CMTimeMake(1, 15);


    if([self.captureSession canAddOutput:self.captureVideoOutput])//check if the capture session can add the output
        [self.captureSession addOutput:self.captureVideoOutput];//add the output to the capture session
    else 
        NSLog(@"Capture Session can't add output");
    
    dispatch_queue_t queue = dispatch_queue_create("Sample Delegate Queue", NULL);
    [self.captureVideoOutput setSampleBufferDelegate:self queue:queue];    
    dispatch_release(queue);
    
    [self.captureVideoOutput release];
}
- (void)addStillImageOutput{

    self.captureStillImageOutput = [[AVCaptureStillImageOutput alloc]init];
    [self.captureStillImageOutput setOutputSettings:[NSDictionary dictionaryWithObjectsAndKeys:AVVideoCodecJPEG,AVVideoCodecKey, nil]];
    
    if([self.captureSession canAddOutput:self.captureStillImageOutput])
        [self.captureSession addOutput:self.captureStillImageOutput];
    else
        NSLog(@"Capture Session could not add still image output");

    [self.captureStillImageOutput release];
    
}

#pragma mark - Capturing Image
- (void)captureImage{
    AVCaptureConnection *videoConnection = nil;
    for(AVCaptureConnection *connection in captureStillImageOutput.connections){           
        for(AVCaptureInputPort *port in connection.inputPorts){
            if([port.mediaType isEqual:AVMediaTypeVideo]){
                videoConnection = connection;
                break;
            }            
        }
        if(videoConnection)
            break;
    }
    
    if(videoConnection)
        [self.captureStillImageOutput captureStillImageAsynchronouslyFromConnection:videoConnection completionHandler:^(CMSampleBufferRef imageDataSampleBuffer, NSError *error) {
            
            if(!error)
                [self imageFromSampleBuffer:imageDataSampleBuffer];
            else
                NSLog(@"%@",error);
        }];

}
- (UIImage*)returnFrame{
    return self.frame;
}
- (void)imageFromSampleBuffer:(CMSampleBufferRef)sampleBuffer{
    
    NSData *imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:sampleBuffer];
    UIImage *image = [UIImage imageWithData:imageData];
    [self setFrame:image];

}


#pragma mark - AVCaptureVideoOutput Delegate
- (void)captureVideoOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection {
    NSLog(@"Capturing Video Frames");    
}

#pragma mark - Memory Management
- (void)dealloc{
    [self.captureVideoOutput release];self.captureVideoOutput = nil;
    [self.captureStillImageOutput release];self.captureStillImageOutput = nil;
    [self.frame release];self.frame = nil;
    [super dealloc];
}
@end

;

ViewController.h

#import <UIKit/UIKit.h>
#import "CameraCaptureManager.h"
@interface CameraEdgeDetectionViewController : UIViewController {
    UIImageView *captureImageView;
    CameraCaptureManager *sessionManager;
}
- (id)init;
- (void)setUpCameraSession;
- (void)takePicture;
- (void)updateImageView;
@property (nonatomic,retain) UIImageView *captureImageView;
@property (nonatomic,retain) CameraCaptureManager *sessionManager;
@end

ViewController.m

#import "CameraEdgeDetectionViewController.h"

@implementation CameraEdgeDetectionViewController
@synthesize sessionManager;
@synthesize captureImageView;

#pragma mark - Initializers
- (id)init{
    self = [super init];
    if(self){
        [self setUpCameraSession];
    }
    return  self;
}

#pragma mark - View lifecycle
- (void)viewDidLoad{
       [super viewDidLoad];
}
- (void)viewDidUnload{
    [super viewDidUnload];
}
- (void)viewDidAppear:(BOOL)animated{
    
    self.captureImageView = [[[UIImageView alloc]init]retain];
    [self.captureImageView setFrame:CGRectMake(30, 30, 50, 50)];
    [self.captureImageView setContentMode:UIViewContentModeScaleAspectFit];
    [self.view addSubview:self.captureImageView];
    
    UIButton *captureButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    [captureButton setFrame:CGRectMake(30, 90, 50, 50)];
    [captureButton addTarget:self action:@selector(takePicture) forControlEvents:UIControlEventTouchDown];
    [self.view addSubview:captureButton];
    
    [super viewDidAppear:animated];    
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation{
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}

#pragma mark - Camera Session
//GOAL:Sets up the camera session and adds the preview layer to the screen
- (void)setUpCameraSession{
    
    //initialize the session manager
    self.sessionManager = [[CameraCaptureManager alloc]init];
    
    //create Previews layer rect and position
    CGRect layerRect = self.view.layer.bounds;
    CGPoint layerPosition = CGPointMake(CGRectGetMidX(layerRect), CGRectGetMidY(layerRect));    
    
    //set the previews layer and rect
    [self.sessionManager.previewLayer setFrame:layerRect];
    [self.sessionManager.previewLayer setPosition:layerPosition];
    
    //add preview layer to views layer
    [self.view.layer addSublayer:self.sessionManager.previewLayer];
    
    //start capture session
    [self.sessionManager.captureSession startRunning];
    [self.sessionManager release];
}

//GOAL:When the user taps the button on the screen this update the imageview to the image taken
- (void)takePicture{
   [self.sessionManager captureImage];
   [self updateImageView];
}
- (void)updateImageView{
   [self.captureImageView setImage:[self.sessionManager returnFrame]];
}

#pragma mark - Memory
- (void)didReceiveMemoryWarning{
    [super didReceiveMemoryWarning];
}
- (void)dealloc{
    [self.captureImageView release];self.captureImageView = nil;
    [self.sessionManager release];self.sessionManager = nil;
    [super dealloc];
}
@end

[smithdale87]

It would be helpful to know what the error message is when your app crashes.

[Esko2300]

Im getting a bad access error when i press the button that calls my take picture method. So im guessing it has something to do with the UIIMageView on the view controller. The console just says bad access and it stops at this line

- (void)takePicture{
    [self.captureImageView setImage:[self.sessionManager captureImage]];//this is where the bad access is happening
}

;

[Esko2300]

Ok i got it turns out that the frame object in my Camera Capture class wasent always being called like self.frame. So it was causing the Bad Access Error I just went in and changed all the frames to self.frame and its working fine now thanks

[Esko2300]

OK im back here on this thread because i have yet another problem ill edit all the code up above after i write this. What happens is the code runs.

When i take a picture of a shirt using the button, i hear the camera click. Then i look to see what pops up in the captureImageView of my view controller but nothing shows. Then i go and take a picture of a cup what happens now is the picture of the shirt is showing in the imageview. Then i take a picture of a pen, but the pixture of the cup shows itself in the imageview. So what im seeing is that its one frame behind and i have no idea where to even start looking for the bug since this is only my second day playing around with this framework. Can anyone see why this is happening?

[Esko2300]

I think i found the problem but i dont know how to fix it. Turns out this function

- (void)takePicture{
   [self.sessionManager captureImage];
   [self updateImageView];
}

is being ran but it dosent wait for the first function to run in order to start the next function. I tried using dispatch_sync() in order to make it run the first function first but to no luck its not working. Hope this helps you help me.

[baja_yu]

Why not set up a notification in CameraCaptureManager to notify the caller class when the image has been taken, and then when you receive the notification you can call the updateImageView method.

[Esko2300]

Originally Posted by baja_yu

Why not set up a notification in CameraCaptureManager to notify the caller class when the image has been taken, and then when you receive the notification you can call the updateImageView method.

Smart idea i never used them b4 but nows the time thanks ill check it out

[Esko2300]

Worked perfectly thanks a lot