Video Recognition Questions Using Darknet yolov2

$./darknet detect cfg/yolo.cfg yolo.weights data/videoplayback.mp4
layer filters size input output
    0 conv32 3 x 3 / 1608 x 608 x 3 - > 608 x 608 x 32
    1 max 2 x 2 / 2 608 x 608 x 32 - > 304 x 304 x 32
    2 conv643 x 3 / 1304 x 304 x 32 - > 304 x 304 x 64
    3 max 2 x 2 / 2 304 x 304 x 64 - > 152 x 152 x 64

omission

   29 conv 1024 3 x 3/1 19 x 19 x 1280 - > 19 x 19 x 19 x 1024
   30 conv 425 1 x 1/19 x 19 x 1024 - > 19 x 19 x 425
   31 detection
mask_scale:Using default '1.000000'
Loading weights from yolo. weights... Done!
Cannot load image "data/videoplayback.mp4"
STB Reason:can't fopen