Actually I wonder why we should have a vector video format in the first place. Would it not be much simpler to render a series of vector images and their transformations directly to a standard video code? I mean all the modern video codecs have vector elements afaik, and most have motion prediction. One could just leave out the whole messy inference and directly tell the decoder "here is a rectangular shape, moving with that speed in this direction", no?
The primitives aren't the same for video codecs as they are for something like flash. Even the transforms you can do are fairly limited. AV1, for example, is partially complex because it allows for some scaling transforms as part of the codec.
The problem is that you could have those concepts in a video codec, but then you'd be in some sort of weird hybrid world. A general encoder would almost certainly never use most of those transforms and primitives. Meanwhile, the decoder would need to understand both to properly render anything. I'd imagine you'd frequently run into cases where the decoder fails simply because whoever wrote it didn't want to be bothered supporting the full set of features for the steam (since encoders don't employ that full feature set).
Then there is the whole danger of having a turing complete video stream format. Last thing you'd want is for someone to publish a bitcoin miner on a youtube video :)
Flash vector animations are infinitely scalable from a very tiny file size. The vectors in modern codecs are motion vectors. They don't generally have any concept of drawing primitives like splines, polygons, fills, gradients, etc., and they are raster formats so they have a fixed native pixel size.
The idea of a vector codec isn't new though, and prior attempts have been made, though I don't remember enough details to find a reference.
Just for anyone who might not be familiar, "vector" in this context refers to the graphics you would generate in a tool like Inkscape, where you can define complex geometric shapes with just a few datapoints. "Raster" graphics are what Gimp works with, where each pixel is specified (effectively) individually.
