Animated effects pixel dimensions best practices for webm format

I've been experimenting with adding realistic animated spell and environmental effects tokens to a game, for 2 purposes:

1) To add some flair for the personal satisfaction of me and my players
2) To learn and explore if I can achieve the necessary quality level to become a Marketplace Contributor

To start off on the right foot, I've reviewed both Best Practices for Files on Roll20 and Creating Marketplace Assets. The Creating Marketplace Assets documentation indicates that tokens should be 280x280 pixels per square in PNG format (though I realize that PNG format does not apply for animations). The Best Practices page suggests that webm format is the most suitable and efficient format for my desired goal of adding realistic animations.

Armed with that information, I created a small animation as a test — a semi-transparent 15-foot diagonal cone of fire. The cone is meant to occupy a 3-square by 3-square area (with 6 fiery squares and 3 empty squares). Using the guidelines in the documentation, I produced an 840x840 animation file in webm format (reflecting 280/square x 3 squares). I added the file to my game, and voilà, it worked. When sized to 3x3 squares (280px/sq), the file appeared as I expected regarding animation, transparency and quality. In fact, it even looked nice when sized to 12x12 squares (70px/sq) as indicated on the Creating Marketplace Assets page.

However, it seemed to tax my system significantly, especially if I placed 2 or 3 instances of the effect. For my own game, I think I'd get around this by simply recreating my file at a smaller size, such as 140px or 70px per square — I imagine I'd find the resulting quality more than passable.

This leads me to 2 questions:

1) Does the 280x280-pixel-per-square recommendation on the Creating Marketplace Assets page apply to webm animations the same as it does for PNGs?
2) How "firm" is that recommendation, assuming I'd like to one day contribute to the marketplace?

Oh hey! I'm also a creator of Animated Marketplace items, so I've dealt with this sorta thing firsthand.

Firstly, at least since I've last checked, I've found no guidelines for animated files anywhere in the Best Practices section of Roll20. Additionally, I've never encountered any of my Marketplace packs being recalled for following the Pixel to Square guidelines, and in fact, I flat out ignore them in my offerings because handling animated tokens is different from static ones when you consider lag.

Multiple instances of any animation will lag out a tabletop, but the lag gets significantly worse the larger the size of the video file. To me, performance is way more important than looks when it comes to playing games. Besides, WEBM compression will butcher fine details in video quality anyway, so in the interest of better performance, I use smaller file sizes.

I usually use 253 x 253 for animations that take 1 square. Why 253? Honestly, it's just what I used and never saw any good reason to switch off of it.

However, if I'm using larger animations, I make sure to never exceed 1000 x 1000. Let's do some math quickly. Let's say I follow the 280 guideline for PNG and want to make a large animation. How large? Let's say, a 60 foot cone. Using the Pathfinder measurements, that's at least going to be 12x16 squares. Or, 3360 Pixels x 4480 Pixels. Adding up to a total of 15,052,800 pixels in the animation.

How big is that number exactly? For reference, 4k Video is 8,294,400 pixels. Our hypothetical 60 foot cone animation is nearly two 4K videos running at the same time. Even if Roll20 was perfectly optimized, that alone would be tricky for most computers to render without lag. Running more than 1 of these animations would reduce a tabletop to Powerpoint.

Since WebM compression is already somewhat lossy, there's no need for this type of high detail that's going to be lost in compression anyway. Persistent animations should have as low a file size that looks good as possible, in my opinion.

That said, the answer to both of your questions is either: No, there is no application of the 280 recommendation, or, there is a recommendation somewhere I can't find it, and it's so loose it practically doesn't matter.

Hope that answered some of your questions. I'd be willing to share more knowledge on the subject if you're interested, so feel free to send me a PM whenever. Looking forward to seeing what you come up with!

EDIT: Oh, I forgot to mention this, but since the application for marketplace creators doesn't have any real requirements, when I asked Roll20 what the requirements were, they simply asked to attach the files in WebM format.

I also should mention, when posting things to the Marketplace, even though the Tabletop itself supports VP9 Encoded WebM files, the Marketplace Uploader only supports VP8 Encoded WebM files, at least since I last checked. So make sure you're able to export to that format before applying!

I've made some animations in the Marketplace as well - I keep to a 140x140 pixel ratio per grid unit up to 10x10 units (1400x1400) - I found that shortly after that size I run into bugs and upload issues. I will enter the suggested size in units in my file name if it as well. So a 15x15 unit animation will be sized as if it were 10x10, but the grid lines will line up at 15x15. It's a slight loss in quality but not very noticable unless you are sizing it far higher than that and zooming in as well.

Also make sure you are rendering VP8, as VP9 is not supported.

Thanks Rainy and Munky! Your answers help a lot!