iPhone SDK: Long animations with "animationImages" problem.

Question

Hello, I have been trying to set up an animation in xcode for a long time now, At first I started trying to animate 100 1000x1000 pngs, but those images were too big for the iphone, now I am trying to animate 100 320x480 pngs and it seems to animate fine up until about 40 frames in, then the app crashes, so, is there any other method of animation that wouldn't do this? It's probably just because this code loads too much images for the iphone to handle, is there some other method i can use to get the app to stop crashing? Or can I optimize this code further? (By the way i'm new to the iphone platform so keep in mind when answering)

- (IBAction)startClick1:(id)sender{

spud123.animationImages = [NSArray arrayWithObjects:
        [UIImage imageNamed: @"spud1230000.png"],
        [UIImage imageNamed: @"spud1230001.png"],
        [UIImage imageNamed: @"spud1230002.png"],
        [UIImage imageNamed: @"spud1230003.png"],
        [UIImage imageNamed: @"spud1230004.png"],
        [UIImage imageNamed: @"spud1230005.png"],
        [UIImage imageNamed: @"spud1230006.png"],
        [UIImage imageNamed: @"spud1230007.png"],
        [UIImage imageNamed: @"spud1230008.png"],
        [UIImage imageNamed: @"spud1230009.png"],
        [UIImage imageNamed: @"spud1230010.png"],
        [UIImage imageNamed: @"spud1230011.png"],
        [UIImage imageNamed: @"spud1230012.png"],
        [UIImage imageNamed: @"spud1230013.png"],
        [UIImage imageNamed: @"spud1230014.png"],
        [UIImage imageNamed: @"spud1230015.png"],
        [UIImage imageNamed: @"spud1230016.png"],
        [UIImage imageNamed: @"spud1230017.png"],
        [UIImage imageNamed: @"spud1230018.png"],
        [UIImage imageNamed: @"spud1230019.png"],
        [UIImage imageNamed: @"spud1230020.png"],
        [UIImage imageNamed: @"spud1230021.png"],
        [UIImage imageNamed: @"spud1230022.png"],
        [UIImage imageNamed: @"spud1230023.png"],
        [UIImage imageNamed: @"spud1230024.png"],
        [UIImage imageNamed: @"spud1230025.png"],
        [UIImage imageNamed: @"spud1230026.png"],
        [UIImage imageNamed: @"spud1230027.png"],
        [UIImage imageNamed: @"spud1230028.png"],
        [UIImage imageNamed: @"spud1230029.png"],
        [UIImage imageNamed: @"spud1230030.png"],
        [UIImage imageNamed: @"spud1230031.png"],
        [UIImage imageNamed: @"spud1230032.png"],
        [UIImage imageNamed: @"spud1230033.png"],
        [UIImage imageNamed: @"spud1230034.png"],
        [UIImage imageNamed: @"spud1230035.png"],
        //and so on to 100
        nil];

[spud123 setAnimationRepeatCount:1];
spud123.animationDuration =5.7;
[spud123 startAnimating];

}

Ps: Iv'e tried NSTimer, but I can't get that to stop repeating the animation

Answer 1

This is not an animation problem it's a design problem.

First off, just take a step cack and calculate your application's memory requirements: When decompressed, each of those PNGs uses 614400 bytes. So a hundred of them use 61440000 bytes: over 60 megabytes. That's a little much to expect from a phone.

If you really need to display a different image for every frame, you should be using video. Video has a lot of technology to compress images and reduce the processing and memory requirements when displaying a lot of large images sequentially.

If you need this to be an animation with more control, I suggest you need to analyse what is moving and only animate that - draw a single background and then animate smaller images over that.

Finally, if this approach doesn't work, you are going to have to learn OpenGL to achieve the performance you need.

Without knowing more about your app, it is difficult to advise.

Answer 2

Often the frames in an animation are very similar. So one potential solution is to load a few images... then animate them using OpenGL. This works well for, say, a ball bouncing. Not sure what images you're animating.

Answer 3

You need to consider your application memory use carefully, but just so you know the options, I've successfully used a modified class based on http://www.modejong.com/iPhone/PNGAnimatorDemo.zip which can, on the first generation iPad hardware, handle 15fps full screen (1024x768) png animations. But keep an eye on your application bundle size. This is definitely not going to be the best option for most applications.

Answer 4

you will use stopAnimating