When I try to extract frames from some videos of the HMDB51 dataset, I find I get fewer frames than expected, the code is

def dump_frames(vid_path):
    # import cv2
    # video = cv2.VideoCapture(vid_path)
    video =
    vid_name = vid_path.split('/')[-1].split('.')[0]
    out_full_path = os.path.join(out_path, vid_name)

    # fcount = int(video.get(cv2.CV_CAP_PROP_FRAME_COUNT))

    fcount = int(video.get(cv2.CAP_PROP_FRAME_COUNT))
    print("Total frame count is", fcount)
    try:
        os.mkdir(out_full_path)
    except OSError:
        pass
    file_list = []
    for i in range(fcount):
        ret, frame = video.read()
        # print(i, fcount)
        # assert ret
        cv2.imwrite('{}\{:06d}.jpg'.format(out_full_path, i), frame)
        access_path = '{}\{:06d}.jpg'.format(vid_name, i)
        file_list.append(access_path)
    print('{} done'.format(vid_name))
    sys.stdout.flush()
    return file_list
dump_frames("April_09_brush_hair_u_nm_np1_ba_goo_0.avi")

How can I get the full number of all the frames?