application crashed when make video from images

Question

Please find the below code.

-(void) writeImagesAsMovie:(NSArray *)array toPath:(NSString*)path numPhoto:(NSInteger)totPics {

    ALAsset *asset = [assets objectAtIndex:0];

    ALAssetRepresentation *assetRepresentation = [asset defaultRepresentation];    
    UIImage *getImage = [UIImage imageWithCGImage:[assetRepresentation fullScreenImage] scale:[assetRepresentation scale] orientation:(UIImageOrientation)[assetRepresentation orientation]];
    UIImage *first = [getImage imageByScalingAndCroppingForSize:CGSizeMake(720.0, 960.0)];

    CGSize frameSize = CGSizeMake(first.size.width,first.size.height);

    NSLog(@"frameSize = %@",NSStringFromCGSize(frameSize));
    NSError *error = nil;
    AVAssetWriter *videoWriter = [[AVAssetWriter alloc] initWithURL:
                                  [NSURL fileURLWithPath:path] fileType:AVFileTypeQuickTimeMovie
                                                              error:&error];

    if(error) {
        NSLog(@"error creating AssetWriter: %@",[error description]);
    }
    NSDictionary *videoSettings = [NSDictionary dictionaryWithObjectsAndKeys:
                                   AVVideoCodecH264, AVVideoCodecKey,
                                   [NSNumber numberWithInt:frameSize.width], AVVideoWidthKey,
                                   [NSNumber numberWithInt:frameSize.height], AVVideoHeightKey,
                                   AVVideoScalingModeResizeAspect,AVVideoScalingModeKey,
                                   nil];


    AVAssetWriterInput* writerInput = [AVAssetWriterInput
                                        assetWriterInputWithMediaType:AVMediaTypeVideo
                                        outputSettings:videoSettings];


    CGAffineTransform transform = CGAffineTransformIdentity;
    UIImageOrientation orient = first.imageOrientation;
    CGSize imageSize = first.size;

    switch(orient) {

        case UIImageOrientationUp: //EXIF = 1
            transform = CGAffineTransformIdentity;
            break;

        case UIImageOrientationUpMirrored: //EXIF = 2
            transform = CGAffineTransformMakeTranslation(imageSize.width, 0.0);
            transform = CGAffineTransformScale(transform, -1.0, 1.0);
            break;

        case UIImageOrientationDown: //EXIF = 3
            transform = CGAffineTransformMakeTranslation(imageSize.width, imageSize.height);
            transform = CGAffineTransformRotate(transform, M_PI);
            break;

        case UIImageOrientationDownMirrored: //EXIF = 4
            transform = CGAffineTransformMakeTranslation(0.0, imageSize.height);
            transform = CGAffineTransformScale(transform, 1.0, -1.0);
            break;

        case UIImageOrientationLeftMirrored: //EXIF = 5

            transform = CGAffineTransformMakeTranslation(imageSize.height, imageSize.width);
            transform = CGAffineTransformScale(transform, -1.0, 1.0);
            transform = CGAffineTransformRotate(transform, 3.0 * M_PI / 2.0);
            break;

        case UIImageOrientationLeft: //EXIF = 6

            transform = CGAffineTransformMakeTranslation(0.0, imageSize.width);
            transform = CGAffineTransformRotate(transform, 3.0 * M_PI / 2.0);
            break;

        case UIImageOrientationRightMirrored: //EXIF = 7

            transform = CGAffineTransformMakeScale(-1.0, 1.0);
            transform = CGAffineTransformRotate(transform, M_PI / 2.0);
            break;

        case UIImageOrientationRight: //EXIF = 8

            transform = CGAffineTransformMakeTranslation(imageSize.height, 0.0);
            transform = CGAffineTransformRotate(transform, M_PI / 2.0);
            break;

        default:
            [NSException raise:NSInternalInconsistencyException format:@"Invalid image orientation"];
    }


    writerInput.transform = transform;

    NSMutableDictionary *attributes = [[NSMutableDictionary alloc] init];
    [attributes setObject:[NSNumber numberWithUnsignedInt:kCVPixelFormatType_32ARGB] forKey:(NSString*)kCVPixelBufferPixelFormatTypeKey];
    [attributes setObject:[NSNumber numberWithUnsignedInt:frameSize.width] forKey:(NSString*)kCVPixelBufferWidthKey];
    [attributes setObject:[NSNumber numberWithUnsignedInt:frameSize.height] forKey:(NSString*)kCVPixelBufferHeightKey];

    AVAssetWriterInputPixelBufferAdaptor *adaptor = [AVAssetWriterInputPixelBufferAdaptor
                                                     assetWriterInputPixelBufferAdaptorWithAssetWriterInput:writerInput
                                                     sourcePixelBufferAttributes:attributes];

    [videoWriter addInput:writerInput];

    // fixes all errors
    writerInput.expectsMediaDataInRealTime = YES;

    //Start a session:
    [videoWriter startWriting];

    [videoWriter startSessionAtSourceTime:kCMTimeZero];

    CVPixelBufferRef buffer = NULL;
    buffer = [self pixelBufferFromCGImage:[first CGImage]];
    BOOL result = [adaptor appendPixelBuffer:buffer withPresentationTime:kCMTimeZero];

    if (result == NO)
        NSLog(@"failed to append buffer");

    if(buffer) {
        CVBufferRelease(buffer);
    }

    int fps = 2;

    for(int i=0; i<totPics; i++)
    {

        if (adaptor.assetWriterInput.readyForMoreMediaData) {


            CMTime frameTime = CMTimeMake(1, fps);
            CMTime lastTime = CMTimeMake(i, fps);


            CMTime presentTime = CMTimeAdd(lastTime, frameTime);
            NSLog(@"presentTime = %f",CMTimeGetSeconds(presentTime));


            ALAsset *asset = [assets objectAtIndex:i];
            ALAssetRepresentation *assetRepresentation = [asset defaultRepresentation];
            UIImage *imgGetFrame = [UIImage imageWithCGImage:[assetRepresentation fullScreenImage] scale:[assetRepresentation scale] orientation:(UIImageOrientation)[assetRepresentation orientation]];
            UIImage *imgFrame = [imgGetFrame imageByScalingAndCroppingForSize:CGSizeMake(720.0, 960.0)];

            buffer = [self pixelBufferFromCGImage:[imgFrame CGImage]];
            BOOL result = [adaptor appendPixelBuffer:buffer withPresentationTime:presentTime];

            if (result == NO) //failes on 3GS, but works on iphone 4
            {
                NSLog(@"failed to append buffer");
                NSLog(@"The error is %@", [videoWriter error]);
            }

            if(buffer) {
                CVBufferRelease(buffer);
            }


        } else {
            NSLog(@"error");
        }        
    }

    //Finish the session:
    [writerInput markAsFinished];
    [videoWriter finishWritingWithCompletionHandler:^{

        NSLog(@"Complete");
    }];

    CVPixelBufferPoolRelease(adaptor.pixelBufferPool);
}    

-(CVPixelBufferRef) pixelBufferFromCGImage: (CGImageRef) image {
NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
                         [NSNumber numberWithBool:YES], kCVPixelBufferCGImageCompatibilityKey,
                         [NSNumber numberWithBool:YES], kCVPixelBufferCGBitmapContextCompatibilityKey,
                         nil];
CVPixelBufferRef pxbuffer = NULL;

CVPixelBufferCreate(kCFAllocatorDefault, CGImageGetWidth(image),
                    CGImageGetHeight(image), kCVPixelFormatType_32ARGB, (__bridge CFDictionaryRef) options,
                    &pxbuffer);

CVPixelBufferLockBaseAddress(pxbuffer, 0);
void *pxdata = CVPixelBufferGetBaseAddress(pxbuffer);

CGColorSpaceRef rgbColorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef context = CGBitmapContextCreate(pxdata, CGImageGetWidth(image),
                                             CGImageGetHeight(image), 8, 4*CGImageGetWidth(image), rgbColorSpace,
                                             kCGImageAlphaNoneSkipFirst);

CGContextConcatCTM(context, CGAffineTransformMakeRotation(0));


CGContextDrawImage(context, CGRectMake(0, 0, CGImageGetWidth(image),
                                       CGImageGetHeight(image)), image);
CGColorSpaceRelease(rgbColorSpace);
CGContextRelease(context);

CVPixelBufferUnlockBaseAddress(pxbuffer, 0);

return pxbuffer;
}

Cropped Image method

-(UIImage*)imageByScalingAndCroppingForSize:(CGSize)targetSize {
UIImage *sourceImage = self;
UIImage *newImage = nil;
CGSize imageSize = sourceImage.size;
CGFloat width = imageSize.width;
CGFloat height = imageSize.height;
CGFloat targetWidth = targetSize.width;
CGFloat targetHeight = targetSize.height;
CGFloat scaleFactor = 0.0;
CGFloat scaledWidth = targetWidth;
CGFloat scaledHeight = targetHeight;
CGPoint thumbnailPoint = CGPointMake(0.0,0.0);

if (CGSizeEqualToSize(imageSize, targetSize) == NO)
{
    CGFloat widthFactor = targetWidth / width;
    CGFloat heightFactor = targetHeight / height;

    if (widthFactor > heightFactor)
    {
        scaleFactor = widthFactor; // scale to fit height
    }
    else
    {
        scaleFactor = heightFactor; // scale to fit width
    }

    scaledWidth  = width * scaleFactor;
    scaledHeight = height * scaleFactor;

    // center the image
    if (widthFactor > heightFactor)
    {
        thumbnailPoint.y = (targetHeight - scaledHeight) * 0.5;
    }
    else
    {
        if (widthFactor < heightFactor)
        {
            thumbnailPoint.x = (targetWidth - scaledWidth) * 0.5;
        }
    }
}

UIGraphicsBeginImageContext(targetSize); // this will crop

CGRect thumbnailRect = CGRectZero;
thumbnailRect.origin = thumbnailPoint;
thumbnailRect.size.width  = scaledWidth;
thumbnailRect.size.height = scaledHeight;

[sourceImage drawInRect:thumbnailRect];

newImage = UIGraphicsGetImageFromCurrentImageContext();

if(newImage == nil) {
    NSLog(@"could not scale image");
}

//pop the context to get back to the default
UIGraphicsEndImageContext();

return newImage;
}

I have pass the image from the user photo library and add the image after crop it to 720 x 960.

When I took 100 images then I got memory warning error. Also when I checked the application in instrument then it took around 400 mb. So please help me if anyone has an idea what I am doing wrong.

Answer 1

The problem is that you are using up all app memory in your video processing loop. You cannot just allocate hundreds of images in memory at the same time, the code will crash when run on your iOS device. Please read my blog post on the subject at video_and_memory_usage_on_ios_devices and then change your for loop so that an autorelease pool is created for each iteration of the loop to fix the runaway memory usage. Also note that kCVPixelFormatType_32ARGB will be very slow, you should use kCVPixelFormatType_32BGRA.