为什么VideoWriter输出的视频周围有黑框？

Question

我正在使用视频编写器来保存FLIR相机的输出。到目前为止，我已经成功，视频文件保存得很好。但是，保存的文件顶部是实际的镜头，周围是黑色。这个屏幕截图将显示我的意思：

起初我以为我只是保存了错误大小的视频，但无论我设置的大小如何，这都会继续发生。我甚至尝试使用cv2.resize()方法，但也失败了。

我似乎找不到其他有这个问题的人，我无法弄清楚我做错了什么。这是我的代码：

  def main(flip_v = False, alpha = 128, device = "/dev/spidev0.0"):
  # Create an array representing a 1280x720 image of
  # a cross through the center of the display. The shape of
  # the array must be of the form (height, width, color)
  a = np.zeros((240, 320, 3), dtype=np.uint8)
  lepton_buf = np.zeros((60, 80, 1), dtype=np.uint16)

  with picamera.PiCamera() as camera:
    # Add the overlay directly into layer 3 with transparency;
    # we can omit the size parameter of add_overlay as the
    # size is the same as the camera's resolution
    o = camera.add_overlay(np.getbuffer(a), size=(320,240), layer=3, alpha=int(alpha), crop=(0,0,80,60), vflip=flip_v)

    #Creating the VideoWriter object
    filename = time.strftime("%Y.%m.%d %H.%M.%S", time.localtime()) + ".avi"
    fourcc = cv2.cv.CV_FOURCC('I', '4', '2', '0')
    out = cv2.VideoWriter(filename, fourcc, 8.0, (60, 80))

with Lepton(device) as l:
        last_nr = 0
        while True:
          _,nr = l.capture(lepton_buf)

          if nr == last_nr:
            # no need to redo this frame
            continue
          last_nr = nr
          cv2.normalize(lepton_buf, lepton_buf, 0, 65535, cv2.NORM_MINMAX)
          np.right_shift(lepton_buf, 8, lepton_buf)
          a[:lepton_buf.shape[0], :lepton_buf.shape[1], :] = lepton_buf

          #resize the frame before writing it to a file
          resized_frame = cv2.resize(a, (60, 80))
          out.write(np.uint8(rezised_frame))

          o.update(np.getbuffer(a))

          # Once the program has run 2000 time break the loop
          k += 1

          if k == 2000:
                 out.release()
                 break