Best practice for high-resolution frame-by-frame bitmap animation

Spritesheets are of course the go-to method for frame-by-frame bitmap animation.

But I think this approach only works up to a point. What if your game requires lots of very high-resolution animations with potentially hundreds of frames of animation in them?

My thought is that a Movie Texture would possibly be the most efficient approach for this - however this is limited greatly depending on the target platform. For example in my case, an Android app, I would have to have all my internal animations fit within Android's video specs.

So, my current thought is to just do it the "stupid" way - having each frame be in its own file, then swapping textures on planes to achieve animation. An optimization could perhaps be storing the animations in video files, but "sampling" the video for images rather than playing the video directly. This would allow me to store the animation in H264 to conserve space.

I'm just wondering if I'm missing something here.