Opencv屏幕录制以错误的速度写入文件

Question

我有一些代码可以捕获屏幕，然后将该图像作为帧写入 mp4。但是，当我再次播放视频时，视频的速度已关闭。我记录了自己运行计时器脚本的过程，秒数几乎以两倍的速度下降。我该怎么办？我遵循的代码是here，在观看视频时也有同样的问题。

这是我修改的一些代码：

def thread_start_recording(out, fps):
    while True:
        img = pyautogui.screenshot()
        frame = np.array(img)
        frame = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)
        out.write(np.array(frame))
        if keyboard.is_pressed('q'):
            break
        time.sleep(1/20)
     out.release()
codec = cv2.VideoWriter_fourcc(*"mp4v")
file_name = "recording.mp4"
fps = 20
out = cv2.VideoWriter(file_name, codec, fps, screensize)
thread = Thread(target=thread_start_recording, args=(out, fps))
thread.start()
thread.join()

Answer 1

我还没有测试过这个，但是，我认为这种方法应该会得到更好的结果，因为睡眠将只是剩余的时间。

import time
def thread_start_recording(out, fps):
    frame_time = 1/fps 
    while True:
        start = time.time() # Start processing
        img = pyautogui.screenshot()
        frame = np.array(img)
        frame = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)
        out.write(np.array(frame))
        if keyboard.is_pressed('q'):
            break

        end = time.time() # End of processing
        # Calculate time until next frame
        work_time = end - start
        sleep_time = frame_time - work_time
        if sleep_time < 0:
            raise Exception("Negative sleep time %s means fps should be reduced" % sleep_time)
        time.sleep(sleep_time)
     out.release()