How many frames are feasible in an animated texture image?

[Paladin Pinion]

I'd like to make an animated image containing as many frames as possible, to get a lifelike animation. If I remember right, we're limited to textures no larger than 1024 pixels square. How many frames could I put into an image that size without making each "cell" so small that all detail and resolution is lost? Has anyone experimented with that? Is there a best-case number?

[Rolig Loon]

I'll pass you a 1024 x 512 texture in world that has 34 cells.  The resolution on it is passable, but nothing to write home about. 

[Chosen Few]

 

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Paladin Pinion wrote:

How many frames could I put into an image that size without making each "cell" so small that all detail and resolution is lost? Has anyone experimented with that?

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There can be no singular answer to that question.  Just as with any non-animated texture, how many pixels you need will be entirely dependent on what details you need the imagery to be able to show.  That factor will vary with every single image you might ever make.

 

To illustrate this, let's go with some extreme examples.  As our first example, let's say you just want to animate a black square to bounce around a white canvas.  The square itself could be as small as a single pixel, and the canvas could be as small as 8x8.  In that case, you could fit 16,384 frames (128 frames per side) on a 1024x1024 filmstrip.  To go to the opposite extreme, say you've got something with a ton of fine elements that have to be very clearly visible, like perhaps a paragraph worth of text that absolutely must remain legible.  In that case, it's unlikely you'd be able to go any smaller than 256x256 per frame before the text would blur too much.  That would give you just 16 frames (4 frames per side), on a 1024x1024.  If it's two paragraphs, you might need 256x512, which would cut it down to 8 frames (4 horizontally x 2 vertically).

As always, the only universally binding answer is this.  Take a good hard look at each texture, on a case by case basis, and make appropriate, intelligent decisions, each and every time.  Beyond that, there's really not much else to say, in terms of a one-size-fits-all kind of response.

 

Now, if it helps you envision what's possible, take a look at your forum avatar portrait.  It's 36x36 pixels.  Obviously, that's enough to make it recognizable as a face.  It's not a particularly detailed face, of course, but it is clearly a human head with a face on it.  Remove 4 pixels from each side, to bring it to 32x32, and it would divide neatly into 1024.  You'd (coincidentally) have 1024 frames (32 frames per side), in that case, which is a TON.  If you were to up it to 128x128, you'd have sixteen times as much room for detail, and 64 frames to work with (8 frames per side).  Generally speaking, that's more than enough for a compelling animation.

The background image your avatar portrait is sitting on is 174x232.  It's got plenty of detail in it.  You could reduce it to 128x256, and it would still look quite good.  On a 1024x1024 filmstrip, that would give you 32 frames (8 horizontally x 4 vertically), with a quite a bit of room for good-looking imagery.

 

Rolig, you mentioned your example has 34 frames.  That's a little bit puzzling.  Was that a typo for 32? 

If it's really 34, how is it arranged?  The only factors of 34 (besides 1 and 34) are 2 and 17.  If your canvas is really 1024x512, then the only frame size that would fit those factors would be roughly 60x256 (assuming you don't just have a bunch of empty space after the final frame). That would be pretty strange, not to mention a bit sloppy looking, since there's no way to divide a power of two evenly by 17.

If it's 32 frames, then each one would be 128x128, in an 8x4 configuration, or 256x64, in a 2x16 configuration.   Either of those would make a heck of a lot more sense.

[Rolig Loon]

Yup, it's 17 x 2.  I'll send it to you. 

[Paladin Pinion]

Thanks Chosen, you've come through again. What you say makes sense and gives me some guidelines. The images I want to use are sky textures, clouds mostly, so I could probably go with much lower resolution than your text example. Mostly I want to avoid any obvious looping effect, which I figured I could do with a long enough animation.

Rolig sent me her example too, which I'll take a look at when I next get in-world. Thanks both of you.