There's a speed-art video that I would like to get its speed back to normal but I'm pretty much new to video editing and such..

The original time of that video is 35:09:30 -- after time remapping, it is 00:30:54. that video is obviously not mine, I don't have its source. So as you may sense, it's gone pretty much insanely high in speed and I would like to know how can I have it back with its original time. That video will happen to be a great tutorial for me so I'll be more than happy if you could assist me. Thank you so much.