iPhone - application stops after saving 50 frames to a movie - iphone

Question

I have several UIImages and I want to create a video from them.
I am used a solution based on this
to create a video from UIImages. In my case, I would like to create a 30 fps video. So, every image is 1/30 of a second.
After setting everything to start saving the video, as mentioned on that page, I have created a method that saves one image to the movie and this method is called by a loop. Something like:
for (int i=0; i<[self.arrayOfFrames count]; i++ {
UIImage *oneImage = [self.arrayOfFrames objectAtIndex:i];
[self saveOneFrame:oneImage atTime:i];
}
and the method is
-(void)saveOneFrame:(UIImage *)imagem atTime:(NSInteger)time {
// I have tried this autorelease pool to drain memory after the method is finished
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
CVPixelBufferRef buffer = NULL;
buffer = [self pixelBufferFromCGImage:imagem.CGImage size:imagem.size];
BOOL append_ok = NO;
int j = 0;
while (!append_ok && j < 30)
{
if (adaptor.assetWriterInput.readyForMoreMediaData)
{
printf("appending %d attemp %d\n", time, j);
CMTime oneFrameLength = CMTimeMake(1, 30.0f ); // one frame = 1/30 s
CMTime lastTime;
CMTime presentTime;
if (time == 0) {
presentTime = CMTimeMake(0, self.FPS);
} else {
lastTime = CMTimeMake(tempo-1, self.FPS);
presentTime = CMTimeAdd(lastTime, duracaoUmFrame);
}
// this will always add 1/30 to every new keyframe
CMTime presentTime = CMTimeAdd(lastTime, oneFrameLength);
append_ok = [adaptor appendPixelBuffer:buffer withPresentationTime:presentTime];
CVPixelBufferPoolRef bufferPool = adaptor.pixelBufferPool;
NSParameterAssert(bufferPool != NULL);
[NSThread sleepForTimeInterval:0.05];
}
else
{
printf("adaptor not ready %d, %d\n", time, j);
[NSThread sleepForTimeInterval:0.1];
}
j++;
}
if (!append_ok) {
printf("error appending image %d times %d\n", time, j);
}
CVBufferRelease(buffer);
[pool drain]; // I have tried with and without this autorelease pool in place... no difference
}
The application simply quits, without any warning, after saving 50 frames to the movie...
This is the other method:
-(CVPixelBufferRef) pixelBufferFromCGImage:(CGImageRef)image size:(CGSize)size
{
NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithBool:YES], kCVPixelBufferCGImageCompatibilityKey,
[NSNumber numberWithBool:YES], kCVPixelBufferCGBitmapContextCompatibilityKey,
nil];
CVPixelBufferRef pxbuffer = NULL;
CVReturn status = CVPixelBufferCreate(kCFAllocatorDefault, size.width,
size.height, kCVPixelFormatType_32ARGB, (CFDictionaryRef) options,
&pxbuffer);
status=status;//Added to make the stupid compiler not show a stupid warning.
NSParameterAssert(status == kCVReturnSuccess && pxbuffer != NULL);
CVPixelBufferLockBaseAddress(pxbuffer, 0);
void *pxdata = CVPixelBufferGetBaseAddress(pxbuffer);
NSParameterAssert(pxdata != NULL);
CGColorSpaceRef rgbColorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef context = CGBitmapContextCreate(pxdata, size.width,
size.height, 8, 4*size.width, rgbColorSpace,
kCGImageAlphaNoneSkipFirst);
NSParameterAssert(context);
//CGContextTranslateCTM(context, 0, CGImageGetHeight(image));
//CGContextScaleCTM(context, 1.0, -1.0);//Flip vertically to account for different origin
CGContextDrawImage(context, CGRectMake(0, 0, CGImageGetWidth(image),
CGImageGetHeight(image)), image);
CGColorSpaceRelease(rgbColorSpace);
CGContextRelease(context);
CVPixelBufferUnlockBaseAddress(pxbuffer, 0);
return pxbuffer;
}
I run instruments and have not detected any leak or exaggerated memory usage that is about the same before the movie starts being saved.
any clues?
NOTE:
After looking at the device logs, I found this:
<Notice>: (UIKitApplication:com.myID.myApp[0xc304]) Bug: launchd_core_logic.c:3732 (25562):3
<Notice>: (UIKitApplication:com.myID.myApp[0xc304]) Assuming job exited: <rdar://problem/5020256>: 10: No child processes
<Warning>: (UIKitApplication:com.myID.myApp[0xc304]) Job appears to have crashed: Segmentation fault: 11
<Warning>: Application 'myApp' exited abnormally with signal 11: Segmentation fault: 11

Answer 1

Maybe you have tried this already but this can help?
In the end, the solution was to restart the iPhone, since some data
got corrupted. After the reboot everything was working normally.
Should have thought of the classic "Have you tried turning it off and
on again?"

Answer 2

Look at it this way, you have an array of images (something which eats a lot of memory). You're making a copy of each one of those images and saving the copy to the finished movie. So your requirements are essentially doubled what you started with. How about if you released each frame after you've added the frame? That will mean that you may end up with the same size (or probably somewhat larger, but still smaller than what you had) memory usage.