memory leak with either array or CGImageRef - ios

Question

I am making a program that strips out frames from a movie. This in Simulator of Xcode 5.0 on iOS 7. The number of objects I am trying to put in this array are 447. (Doesn't seem that many).
My program continuously crashes due to a memory leak either due to array size not being large enough?? (no idea if this statement is right) or due to something else. It consistently fails in the for loop only for vidoes whose number of frames are greater than 350. Less frame videos work fine.
Just a hunch could it have anything to do with the fact that I am storing large original frame images into an array? I am not scaling the frame pics down?
CODE:
NSMutableArray* allFrames = [[NSMutableArray alloc] init];
// get each frame
for (int k=0; k< totalFrames; k++)
{
int timeValue = timeValuePerFrame * k;
CMTime frameTime;
frameTime.value = timeValue;
frameTime.timescale = movie.duration.timescale;
frameTime.flags = movie.duration.flags;
frameTime.epoch = movie.duration.epoch;
CMTime gotTime;
CGImageRef myRef = [generator copyCGImageAtTime:frameTime actualTime:&gotTime error:nil];
[allFrames addObject:[UIImage imageWithCGImage:myRef]];
if (gotTime.value != frameTime.value)
NSLog (#"requested %lld got %lld for k %d", frameTime.value, gotTime.value, k);
//cleanup?
CFRelease(myRef);
}
ERROR:
2013-11-03 20:18:24.746 test[42139:a0b] requested 9925 got 9921 for k 397
2013-11-03 20:18:25.122 test[42139:a0b] requested 9950 got 9946 for k 398
everseHD(42046,0xb029b000) malloc: *** mmap(size=8298496) failed (error code=12)
*** error: can't allocate region
*** set a breakpoint in malloc_error_break to debug
2013-11-03 20:10:31.936 ReverseHD[42046:a0b] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[__NSArrayM insertObject:atIndex:]: object cannot be nil'
*** First throw call stack:
(
0 CoreFoundation 0x020305e4 __exceptionPreprocess + 180
1 libobjc.A.dylib 0x01db38b6 objc_exception_throw + 44
2 CoreFoundation 0x01fe2c3c -[__NSArrayM insertObject:atIndex:] + 844
3 CoreFoundation 0x01fe28e0 -[__NSArrayM addObject:] + 64
4 ReverseHD 0x00003131 -[v1ViewController extractImagesFromMovie] + 3089
5 libobjc.A.dylib 0x01dc5874 -[NSObject performSelector:withObject:withObject:] + 77
6 UIKit 0x00b27c8c -[UIApplication sendAction:to:from:forEvent:] + 108
7 UIKit 0x00b27c18 -[UIApplication sendAction:toTarget:fromSender:forEvent:] + 61
8 UIKit 0x00c1f6d9 -[UIControl sendAction:to:forEvent:] + 66
9 UIKit 0x00c1fa9c -[UIControl _sendActionsForEvents:withEvent:] + 577
10 UIKit 0x00c1e815 -[UIControl touchesBegan:withEvent:] + 254
11 UIKit 0x00b64efb -[UIWindow _sendTouchesForEvent:] + 386
12 UIKit 0x00b65d34 -[UIWindow sendEvent:] + 1232
13 UIKit 0x00b39a36 -[UIApplication sendEvent:] + 242
14 UIKit 0x00b23d9f _UIApplicationHandleEventQueue + 11421
15 CoreFoundation 0x01fb98af __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 15
16 CoreFoundation 0x01fb923b __CFRunLoopDoSources0 + 235
17 CoreFoundation 0x01fd630e __CFRunLoopRun + 910
18 CoreFoundation 0x01fd5b33 CFRunLoopRunSpecific + 467
19 CoreFoundation 0x01fd594b CFRunLoopRunInMode + 123
20 GraphicsServices 0x032239d7 GSEventRunModal + 192
21 GraphicsServices 0x032237fe GSEventRun + 104
22 UIKit 0x00b2694b UIApplicationMain + 1225
23 ReverseHD 0x0000244d main + 141
24 libdyld.dylib 0x02975725 start + 0
)
libc++abi.dylib: terminating with uncaught exception of type NSException

Answer 1

Memory leak ⇒ lots of memory used
Lots of memory used ⇏ memory leak
You are correctly releasing myRef, which you own since it was created with a copy method, so the code you posted doesn't present any leak.
You are just using a lot of memory by trying to store 447 images.
Doesn't seem that many
is not a good evaluation. You should profile the application using Instruments with the Memory Allocation template and check for the size of the array, which is probably filling all the heap.
If you find out that the frames are too big to be stored in the array, you can reduce the size of the generated frame by using the maximumSize property of AVAssetImageGenerator, for instance
generator.maximumSize = CGSizeMake(320, 180);
As stated in the documentation:
The default value is CGSizeZero, which specifies the asset’s unscaled dimensions.