t2v is text-to-video, i2v is image-to-video, and r2v is reference-to-video.
Video generation is asynchronous. Submit the job to POST /v1/video/generations, then poll GET /v1/video/generations/{task_id} until it finishes. See Retrieve a video generation task.
Supported HappyHorse models
Current prices for these models are on aisa.one/models.