cap.isOpened() always returns false

Input #0, mpeg, from ‘sample.mp4’:
Duration: 00:00:13.28, start: 0.533367, bitrate: 341 kb/s
Stream #0:0[0x1e0]: Video: mpeg1video, yuv420p(tv), 640x360 [SAR 1:1 DAR 16:9], 104857 kb/s, 29.97 fps, 29.97 tbr, 90k tbn

The files are in the directory
image

(my code is 64 bits)