How to select correct NUM_FRAMES and SAMPLING_RATE for a different frame rate?

Thanks for sharing this great resources. Just want to confirm if my understanding about NUM_FRAMES=32 and SAMPLING_RATE=2 is correct. I hope to reduce the "frame rate" for my application to see how bad the prediction performance will become, so I found these two parameters in the yaml file.

For NUM_FRAMES=32, does that mean dataloader will pick every 32 frames from the entire video clip if the video was saved as 320 frames? For example, the selected indices will be 1, 32, 64, 96, 128, ... , 320 (Totally 32 frames)

But if I change NUM_FRAMES=16, the data loader will pick every 64 frames, and selected frames will be 1, 64, 128, 192, ... 320 (Totally 16 frames, smaller than 32, but still represent the entire video [1 ~ 320]). Is my understanding correct?

However, what is this SAMPLING_RATE=2 in this setup? Could someone provide some guidance on this?