Question

我要编写这段python来显示来自网络摄像头的视频流，同时记录该视频-我已经开始工作，但是我已将视频流灰度化到屏幕上并加了时间戳它-但是我录制的视频是彩色的！我在下面添加了代码-我尝试使用一些全局变量，但没有用-任何帮助，都非常感谢

import cv2
import numpy as np
import time, datetime
import os


genericfilename = "recording"
filetime = str(time.time())
extension = '.avi'
filename = genericfilename + filetime +extension
frames_per_second = 100
res = '720p'
print("NEW FILE NAME: " + filename)

# Set resolution for the video capture
def change_res(cap, width, height):
cap.set(3, width)
cap.set(4, height)

# Standard Video Dimensions Sizes
STD_DIMENSIONS =  {
"480p": (640, 480),
"720p": (1280, 720),
"1080p": (1920, 1080),
"4k": (3840, 2160),
}


# grab resolution dimensions and set video capture to it.
def get_dims(cap, res='1080p'):
width, height = STD_DIMENSIONS["480p"]
if res in STD_DIMENSIONS:
    width,height = STD_DIMENSIONS[res]
## change the current caputre device
## to the resulting resolution
change_res(cap, width, height)
return width, height

# Video Encoding, might require additional installs
VIDEO_TYPE = {
'avi': cv2.VideoWriter_fourcc(*'XVID'),
#'mp4': cv2.VideoWriter_fourcc(*'H264'),
'mp4': cv2.VideoWriter_fourcc(*'XVID'),
}

def get_video_type(filename):
filename, ext = os.path.splitext(filename)
if ext in VIDEO_TYPE:
  return  VIDEO_TYPE[ext]
return VIDEO_TYPE['avi']

capture = cv2.VideoCapture(0)
out = cv2.VideoWriter(filename, get_video_type(filename), 60, 
get_dims(capture, res))

while(True):
ret, frame = capture.read()
out.write(frame)
grayFrame = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
font = cv2.FONT_ITALIC = 1
cv2.putText(grayFrame, str(datetime.datetime.now()), (-330, 460), font, 3, 
(200, 200, 200), 2, cv2.LINE_AA)
cv2.imshow('combilift output', grayFrame)
# Press Q on keyboard to  exit 
if cv2.waitKey(1) & 0xFF == ord('q'): 
  break
if cv2.waitKey(1) & 0xFF == ord('r'):
    print(datetime.datetime.now())

capture.release()
out.release()
cv2.destroyAllWindows()

Answer 1

将帧保存为视频，然后将帧转换为灰色。

out.write(frame)
grayFrame = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

如果您希望录制的视频为灰色，也许可以颠倒操作顺序并保存grayFrame？

grayFrame = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
out.write(grayFrame)

如果您还想保存文本，请在编写框架之前将文本放在输出中。

Answer 2

让我们看看您的代码

out = cv2.VideoWriter(filename, get_video_type(filename), 60, 
.....
while(True):
ret, frame = capture.read()
out.write(frame)
grayFrame = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

首先保存，然后转换颜色

正确的顺序应该是

out = cv2.VideoWriter(filename, get_video_type(filename), 60, 
.....
while(True):
ret, frame = capture.read()
grayFrame = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
out.write(grayFrame)

我没有要测试的数据。以防万一您遇到一些频道问题。您可以使用opencv merge（grayFrame，grayFrame，grayFrame）创建普通的3通道灰度图像并保存到视频

如何使用全局变量解决Opencv VideoWriter问题

2 个答案: