Objective -C How to create a video from an NSMutableArray? - ios

Question

I have an NSMutableArray of images I need to create a video and save as .mp4 format
I tried a code found in many places to produce a video from images. But it does not work. It creates a blank file
-(void)writeImageAsMovie:(NSArray *)array toPath:(NSString*)path size:(CGSize)size duration:(int)duration
{
NSError *error = nil;
AVAssetWriter *videoWriter = [[AVAssetWriter alloc] initWithURL:
[NSURL fileURLWithPath:path] fileType:AVFileTypeQuickTimeMovie
error:&error];
NSParameterAssert(videoWriter);
NSDictionary *videoSettings = [NSDictionary dictionaryWithObjectsAndKeys:
AVVideoCodecH264, AVVideoCodecKey,
[NSNumber numberWithInt:size.width], AVVideoWidthKey,
[NSNumber numberWithInt:size.height], AVVideoHeightKey,
nil];
AVAssetWriterInput* writerInput = [AVAssetWriterInput
assetWriterInputWithMediaType:AVMediaTypeVideo
outputSettings:videoSettings];
AVAssetWriterInputPixelBufferAdaptor *adaptor = [AVAssetWriterInputPixelBufferAdaptor
assetWriterInputPixelBufferAdaptorWithAssetWriterInput:writerInput
sourcePixelBufferAttributes:nil];
NSParameterAssert(writerInput);
NSParameterAssert([videoWriter canAddInput:writerInput]);
[videoWriter addInput:writerInput];
//Start a session:
[videoWriter startWriting];
[videoWriter startSessionAtSourceTime:kCMTimeZero];
CVPixelBufferRef buffer = NULL;
//convert uiimage to CGImage.
for (int i = 0; i < [array count]; i++) { //NSMutableArray
buffer = [self pixelBufferFromCGImage:[[array objectAtIndex:i] CGImage]];
NSLog(#"%#",[[array objectAtIndex:i] CGImage]);
}
[adaptor appendPixelBuffer:buffer withPresentationTime:kCMTimeZero];
//Write samples:
//Finish the session:
[writerInput markAsFinished];
}
-(CVPixelBufferRef) pixelBufferFromCGImage: (CGImageRef) image
{
NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithBool:YES], kCVPixelBufferCGImageCompatibilityKey,
[NSNumber numberWithBool:YES], kCVPixelBufferCGBitmapContextCompatibilityKey,
nil];
CVPixelBufferRef pxbuffer = NULL;
CVReturn status = CVPixelBufferCreate(kCFAllocatorDefault, self.view.frame.size.width,
self.view.frame.size.height, kCVPixelFormatType_32ARGB, (CFDictionaryRef) options,
&pxbuffer);
NSParameterAssert(status == kCVReturnSuccess && pxbuffer != NULL);
CVPixelBufferLockBaseAddress(pxbuffer, 0);
void *pxdata = CVPixelBufferGetBaseAddress(pxbuffer);
NSParameterAssert(pxdata != NULL);
CGColorSpaceRef rgbColorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef context = CGBitmapContextCreate(pxdata, self.view.frame.size.width,
self.view.frame.size.height, 8, 4*self.view.frame.size.width, rgbColorSpace,
kCGImageAlphaNoneSkipFirst);
NSParameterAssert(context);
CGContextConcatCTM(context, CGAffineTransformMakeRotation(0));
CGContextDrawImage(context, CGRectMake(0, 0, CGImageGetWidth(image),
CGImageGetHeight(image)), image);
CGColorSpaceRelease(rgbColorSpace);
CGContextRelease(context);
CVPixelBufferUnlockBaseAddress(pxbuffer, 0);
return pxbuffer;
}
What is wrong?
Can anyone help me to find a solution please?
Is there any other way that I can create video from images?

Answer 1

Use [videowriter finishWriting]; after [writerInput markAsFinished];
in writeImageAsMovie method.
In ios7 its deprecated ,so use
[videoWriter finishWritingWithCompletionHandler:^(){
NSLog (#"finished writing");
}];
this is very important for the video creation.Thus solved the issue.
Thanks to all for the help.