I have a list of png images that I want them to show one after another to show an animation. In most of my cases I use a UIImageView with animationImages and it works fine. But in a couple of cases my pngs are 1280*768 (full screen iPad) animations with 100+ frames. I see that using the UIImageView is quite slow on the emulator (too long to load for the first time) and I believe that if I put it on the device it will be even slower.
Is there any alternative that can make show an image sequence quite smoothly? Maybe Core Animation? Is there any working example I can see?
Core Animation can be used for vector/key-frame based animation - not image sequences. Loading over a hundred full-screen PNGs on an iPad is a really bad idea, you'll almost certainly get a memory warning if not outright termination.
You should be using a video to display these kind of animations. Performance will be considerably better. Is there any reason why you couldn't use a H.264 video for your animation?
Make a video of your pictures. It is the simplest and probably most reasonable approach.
If you want really good performance and full control over your animation, you can convert the pictures to pvrtc4 format and draw them as billboards (textured sprites) with OpenGL. This can be a lot of work if you don't know how to do it.
Look at the second example
http://www.modejong.com/iPhone/
Extracts from http://www.modejong.com/iPhone/
There is also the UIImageView.animationImages API, but it quickly sucks up all the system memory when using more than a couple of decent size images.
I wanted to show a full screen animation that lasts 2 seconds, at 15 FPS that is a total of 30 PNG images of size 480x320. This example implements an animation oriented view controller that simply waits to read the PNG image data for a frame until it is needed.
Instead of alllocating many megabytes, this class run in about a half a meg of memory with about a 5-10% CPU utilization on a 2nd gen iPhone. This example has also been updated to include the ability to optionally play an audio file via AVAudioPlayer as the animation is displayed.
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I have an animation which consists of 250 frames. Each frame is 1080x1920 resolution and in PNG format. I need to take all these frames, animate them with CAKeyframeAnimation and render them on a video using AVFoundation tools.
The issue arises when I try to create a values array for CAKeyframeAnimation. Initializing 250 FullHD images causes quite a big memory spike, which system detects and decides to kill the app.
I've tried playing with autoreleasepool but it doesn't seem to help at all (no wonder, because CAKeyframeAnimation needs to hold on those images).
The problem goes even further: I actually have 10 of such animations! And I need to quickly switch between them because the app allows to preview those animations dynamically (which is done via AVSynchronizedLayer) before exporting everything in a video file.
So my question is: how can I load a big array of UIImage instances without system killing the app because of a memory surge? Is there an asynchronous way of loading them?
how can I load a big array of UIImage instances without system killing the app because of a memory surge?
You can't. What you're trying to do is wrong from the outset.
If the goal is to make a "sprite animation" by using keyframe animation to change a layer's content periodically, the animation should consist of a small number of small images.
If the goal is to make a video based on a succession of images, a keyframe animation is not how to do it in the first place.
I looked into inverse kinematics as a way of using animation, but overall thought I might want to proceed with using sprite texture atlases to create animation instead. The only thing is i'm concerned about size..
I wanted to ask for some help in the "overall global solution":
I will have 100 monsters. Each has 25 frames of animation for an attack, idle, and spawning animation. Thus 75 frames in total per monster.
I'd imagine I want to do 3x, 2x and 1x animations so that means even more frames (75 x 3 images per monster). Unless I do pdf vectors then it's just one size.
Is this approach just too much in terms of size? 25 frames of animation alone was 4MB on the hard disk, but i'm not sure what happens in terms of compression when you load that into the Xcode and texture atlas.
Does anyone know if this approach i'm embarking on will take up a lot of space and potentially be a poor decision long term if I want even more monsters (right now I only have a few monsters and other images and i'm already up to ~150MB when I go to the app on the phone and look at it's storage - so it's hard to tell what would happen in the long term with way more monsters but I feel like it would be prohibitively large like 4GB+).
To me, this sounds like the wrong approach, and yet everywhere I read, they encourage using sprites and atlases accordingly. What am I doing wrong? too many frames of animation? too many monsters?
Thanks!
So, you are correct that you will run into a problem. In general, the tutorials you find online simply ignore this issue of download side and memory use on device. When building a real game you will need to consider total download size and the amount of memory on the actual device when rendering multiple animations at the same time on screen. There are 3 approaches, just store everything as PNG, make use of an animation format that compresses better than PNG, or third you can encode things as H264. Each of these approaches has issues. If you would like to take a look at my solution to the memory use issue at runtime, have a peek at SpriteKitFireAnimation link at this question. If you want to roll your own approach with H264, you can get lots of compression but you will have issues with alpha channel support. The lazy thing to do is use PNGs, it will work and support alpha channel, but PNGs will bloat your app and runtime memory use is heavy.
I'm looking for solution of animation about 50 images on retina iPad each has 2048*1536 size. I want to animate them on finger move(change images on uiimageview sync with touches moved event). Images loads slowly and animation freezes. I want to find any solution to solve that problem. Thanks.
There are a couple of issues that make this situation very hard to deal with. First, the memory usage of 50 full screen images is very large. For some background on how much memory that actually requires, see this blog post Video and Memory usage on iOS devices. The second issue you have run into is CPU usage. A retina iPad has multiple CPUs, but decoding huge PNG images still takes a lot of CPU cycles and that will prevent the animations from running smoothly. So, the only way you will get this to work well is to avoid decoding the image data at runtime and also avoid holding all the decoded data in memory because that would crash the device. The best solution is to simply mmap() all the decoded data and decode it ahead of time, that makes it possible to blit image data into CoreGraphics without actually having to copy the data. If you would like to use my library that does all that, it is linked at the bottom of the blog post.
I just crashed against the fact that cramming 60 960x640 PNG files into an UIImageView is a terrible mistake.
That said, I'm still required to show this animation, and since it's supposed to have a transparent background, I can't go for a MPMoviePlayer or something like that (or can I?). Besides, even if I could separate the different elements of the animation (which I can't without going to the guy who gave it to me) most of them are still quite large.
I'm at a complete loss for ideas. Do you have any?
Sounds like you might be better suited playing a video, but I'm not sure about the transparent background. Using separate pngs, you have to load each one into memory, which is (640 * 960) pixels * 24 bits/pixels * 60 images = a lot of memory.
That said, how fast do you need to play the animation? Instead of using UIImageView animations, you could use a timer and manually manage loading and unloading of the images into memory, only keeping around one or two at a time.
I have a three-second PNG sequence (a logo animation) that I'd like to display right after my iOS app launches. Since this is the only animated sequence in the app, I'd prefer not to use Cocos2D.
But with UIImageView's animationImages, the app runs out of memory on iPod Touch devices.
Is there more memory-conscious/efficient way to show this animation? Perhaps a sprite sheet class that doesn't involve Cocos2D? Or something else?
If this is an animated splash screen or similar, note that the HIG frowns on such behavior (outside of fullscreen games, at least).
If you're undeterred by such arguments (or making a game), you might consider saving your animation as an MPEG-4 video and using MPMoviePlayerController to present it. With a good compressor, it should be possible to get the size and memory usage down quite a lot and still have a good quality logo animation.
I doubt you're going to find much improvement any other way -- a sprite sheet, for example, is still going to be doing the same kind of work as as sequence of PNGs. The problem is that for most animations, a lot of the pixels are untouched from frame to frame... if you're presenting it just as a series of images, you're wasting a lot of time and space on temporally duplicated pixels. This is why we have video codecs.
You could try manually loading/unloading the png images as needed. I don't know what your frame rate requirements are. Also, consider a decent-quality jpg or animated gif. And you can always make the image smaller so it doesn't take up the whole screen. Just a few thoughts.