Longer videos and textual inversions and fp16 autocast

[dajes]

1. Added the ability to choose separately the length of a video and the size of the context of the temporal attention module. By using a sliding window of attention it is now possible to generate infinitely long GIFs.
   Sliding window related parameters:
   --L - the length of the generated animation.
   --context_length - the length of the sliding window (limited by motion modules capacity), default to L.
   --context_overlap - how much neighbouring contexts overlap. By default context_length / 2
   --context_stride - (2^context_stride) is a max stride between 2 neighbour frames. By default 0

2. Added support for .pt textual inversions from civit.ai that should be put in models/embeddings directory. Though I'm not very sure if this implementation is fully correct, but works fine for me.

3. Now inference automatically uses torch.autocast to fp16 if --fp32 is not specified. It sped things up by 100% in my tests.

[xdomiall]

Thank you dajes for your contribution! I've tested the fp16 autocast on my 4090 and the speed increases are x4. From 55s per gif I went down to 15s/gif. So 200% increase for me

[Cubey42]

Any chance you would be interested in figuring out how to add embeddings or the context stride to this repo? https://github.com/neggles/animatediff-cli

[Cubey42]

Any chance you would be interested in figuring out how to add embeddings or the context stride to this repo? https://github.com/neggles/animatediff-cli

actually I was able to get it to work, nevermind!

[Bendito999]

Just a reminder, for users looking at this who have an old Maxwell card like the Tesla M40 , the fp16 mode actually causes a 3x slowdown instead of 3x speed boost, so use fp32 for Maxwell cards. Maxwell doesn't have dedicated fp16 hardware. Found this out the hard way haha.

[JACKHAHA363]

Is this PR merged any where?

[dajes]

Is this PR merged any where?

AFAIK this technique is used in https://github.com/neggles/animatediff-cli https://github.com/magic-research/magic-animate