I just did a video to video test on hunyuanvideo and it worked great, 101 frames took 259s. 4090

huanyuanvideo's 13 billion parameters look good, using the extensions https://github.com/kijai/ComfyUI-HunyuanVideoWrapper

This workflow is available with the nodes:

https://github.com/kijai/ComfyUI-HunyuanVideoWrapper/blob/main/examples/hyvideo_v2v_example_01.json

The source video is from pexels:

https://www.pexels.com/video/a-4x4-vehicle-speeding-on-a-dirt-road-during-a-competition-15604814/

Run online:

https://www.comfyonline.app/explore/c862f2c9-4903-48b7-90a6-60c4c6bfc557