What is the function of add_time_ids in controlnet sdxl training ?

[xinli2008]

Hi, guys! I am trying to training controlnet-xs sdxl, and i found a parameter in computed_embedding as follows :

Question1: Can you explain for me what this add_time_ids parameter does?
Question2: The first time I trained, the resolution of both the original image and the target image were 512, so I could set 512.
Now I'm trying to use multi-resolution, put different buckets into different resolutions for training, and the image size here is not a fixed 512, so how should I set the args.resolution parameter here?
@kig @kashif @levi @takuma104 @up_the_irons