OutOfMemory while drawing images

Programming Questions

tidensbarn

OutOfMemory while drawing images

in Programming Questions • 1 year ago

Hi,

this little "videoplayer" is supposed to load all the image files from a specified folder into a PImage-Array and draw them one after the other.
Problem is, it generates an OutOfMemory after drawing 53 to 54 frames. If I make it start from the beginning after frame 50 or so, everything works fine. It makes no sense to me. Shouldn't all the images have already been stored in the RAM after loading them into the array? Besides, there are only about 65 files in my test folder with a total size of 30MB, while my sketch can use up to 250MB of RAM..

PImage[] rgbs;
int frame = 0, numpics;

void setup()
{
String path = selectFolder();
File file = new File(path);
String[] filenames = file.list();
numpics= filenames.length;
rgbs = new PImage[numpics];
for(int i=0;i<numpics;i++)
rgbs[i] = loadImage(path+"/"+filenames[i]);
size(rgbs[0].width,rgbs[0].height);
frameRate(12);
}

void draw()
{
image(rgbs[frame],0,0);
frame = frame < numpics-1? frame+1 : 0;
println(frame);
}

Replies(3)

PhiLho

Re: OutOfMemory while drawing images

1 year ago

You make a quite common mistake in this kind of program.
Let's take a semi-random image from my hard disk: it is a Jpeg photography, 1024x768, weighting 548 KB (a quite high quality setting).
Indeed, 65 similar files with weight 35,620 KB, 34 MB. Not that much.
Now, when Processing load them in memory, it uncompress them and each pixel takes 4 bytes in memory (RGBA, even if A isn't used). That's 1024x768x4 = 3,145,728 = 3 MB per image!
65 images = 195 MB, much more than you thought.
And some temporary memory might remain used for a while, too (until garbage collected).

Now, you can just go to Processing preferences and set the memory allocation to a higher setting (but you might be limited around 1.5 GB).

tidensbarn

Re: OutOfMemory while drawing images

1 year ago

I see... isn't there a way to free up the memory after each pass? After all, there needs to be only one image on the screen at a time.

PhiLho

Re: OutOfMemory while drawing images

1 year ago

Well, load each image one after the other. But this won't be as fluid as if you load all of them beforehand (but it will start faster).
Some people load images in a separate thread to avoid the slowdown. Perhaps by loading a couple of images first, then managing a small queue. Not sure if that's a real solution.
Of course, if you have a computer fast enough (CPU and disk speed, and image size!) to load an image fast enough, there might be no problems at all.