NSLT Understanding

I'm a beginner and I have several questions about nlst files. In nslt files, there are lines like {"65097": {"subset": "train", "action": [481, 1, 74]}. Does 1 and 74 is frame_start and frame_end ? And if yes, when I calculate the total frame values, I see that the frame_end values sometimes exceed the total frame, for instance,

filename	frames	fps	duration_sec
/content/videos/65097.mp4	65097.mp4	71	23.976046466253432

Can you give me some solutions for this?