如何禁用OpenCV摄像头中的缓冲区？

import cv2
import v4l2
import fcntl

video_device = '/dev/video0'  # 摄像头设备路径
cap = cv2.VideoCapture(video_device)

fd = cap.get(cv2.CAP_PROP_POS_MSEC)

buf_type = v4l2.V4L2_BUF_TYPE_VIDEO_CAPTURE
buf = v4l2.v4l2_buffer()
buf.type = buf_type
buf.memory = v4l2.V4L2_MEMORY_MMAP
buf.index = 0  # 缓冲区索引

# 获取缓冲区参数
fcntl.ioctl(fd, v4l2.VIDIOC_QUERYBUF, buf)

# 映射缓冲区到用户空间
buffer = mmap.mmap(fd, buf.length, mmap.MAP_SHARED, mmap.PROT_READ | mmap.PROT_WRITE, offset=buf.m.offset)

# 清空缓冲区
buffer.seek(0)
buffer.write(b'\x00' * buf.length)
buffer.flush()

cap.release()