如何用cv2和MTCNN写视频？我正面临着fourcc的问题

import cv2
from mtcnn import MTCNN

# 加载MTCNN模型
detector = MTCNN()

# 打开视频文件
video = cv2.VideoCapture('input.mp4')

# 获取视频的宽度和高度
width = int(video.get(cv2.CAP_PROP_FRAME_WIDTH))
height = int(video.get(cv2.CAP_PROP_FRAME_HEIGHT))

# 创建输出视频文件
fourcc = cv2.VideoWriter_fourcc(*'XVID')
output = cv2.VideoWriter('output.mp4', fourcc, 20.0, (width, height))

# 逐帧处理视频
while video.isOpened():
    ret, frame = video.read()
    if not ret:
        break

    # 使用MTCNN检测人脸
    result = detector.detect_faces(frame)
    for face in result:
        # 绘制人脸框
        x, y, w, h = face['box']
        cv2.rectangle(frame, (x, y), (x+w, y+h), (255, 0, 0), 2)

    # 写入输出视频文件
    output.write(frame)

    # 显示处理后的视频帧
    cv2.imshow('Video', frame)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

# 释放资源
video.release()
output.release()
cv2.destroyAllWindows()