问题描述
我正在尝试向我的应用程序添加高 FPS 屏幕录像机。
我在 Windows 上使用 Python 3.7。
我尝试过的模块和方法是 mss (python-mss) 和 d3dshot，但对于长视频（超过 20 秒），我仍然只能达到 15-19 FPS。
我录制的分辨率是 1920 x 1080。
优化屏幕录制的最佳方法是什么？我曾尝试使用 multiprocessing 库，但似乎仍然不够快。我不确定我是否以最佳方式使用它，我可以通过哪些方式使用它来提高处理性能？
使用 OBS Studio，无论视频有多长，我都能获得 30 FPS。我的目标是用我自己的代码实现相同的结果。
这是我目前所写的：
from multiprocessing import Process,Queue
from time import sleep,time
import cv2
import d3dshot
import numpy as np
def grab(queue):
d = d3dshot.create(capture_output="numpy",frame_buffer_size=500)
d.capture()
sleep(0.1)
c=0
begin = time()
while time() - begin < 30:
starter = time()
frame = d.get_latest_frame()
queue.put(frame)
c+=1
ender = time()
sleep(max(0,1/60 - (ender -starter)))
# Tell the other worker to stop
queue.put(None)
final=time()
print(c/(final-begin))
d.stop()
def save(queue):
SCREEN_SIZE = 1920,1080
# Define the codec and create VideoWriter object
fourcc = cv2.VideoWriter_fourcc(*'DIVX') # In Windows: DIVX
out = cv2.VideoWriter(r"output.avi",fourcc,30.0,(SCREEN_SIZE))
# type: (Queue) -> None
last_img = None
while "there are screenshots":
img = queue.get()
if img is None:
break
if img is last_img:
continue
out.write(cv2.cvtColor(img,cv2.COLOR_BGR2RGB))
last_img = img
if __name__ == "__main__":
# The screenshots queue
queue = Queue() # type: Queue
# 2 processes: one for grabing and one for saving PNG files
Process(target=grab,args=(queue,)).start()
Process(target=save,)).start()
解决方法
我在尝试为游戏进行高速录制时遇到了同样的问题。这是我为 Windows 找到的最快的解决方案。该代码使用原始缓冲区对象并导致大约 27 FPS。我找不到此代码所基于的原始帖子，但如果有人找到它，我会添加参考。
请注意，如果您将区域设置为小于 1920x1080，帧率会显着增加。
"""
Alternative screen capture device,when there is no camera of webcam connected
to the desktop.
"""
import logging
import sys
import time
import cv2
import numpy as np
if sys.platform == 'win32':
import win32gui,win32ui,win32con,win32api
else:
logging.warning(f"Screen capture is not supported on platform: `{sys.platform}`")
from collections import namedtuple
class ScreenCapture:
"""
Captures a fixed region of the total screen. If no region is given
it will take the full screen size.
region_ltrb: Tuple[int,int,int]
Specific region that has to be taken from the screen using
the top left `x` and `y`,bottom right `x` and `y` (ltrb coordinates).
"""
__region = namedtuple('region',('x','y','width','height'))
def __init__(self,region_ltrb=None):
self.region = region_ltrb
self.hwin = win32gui.GetDesktopWindow()
# Time management
self._time_start = time.time()
self._time_taken = 0
self._time_average = 0.04
def __getitem__(self,item):
return self.screenshot()
def __next__(self):
return self.screenshot()
def __enter__(self):
return self
def __exit__(self,exc_type,exc_val,exc_tb):
self.close()
if exc_type and isinstance(exc_val,StopIteration):
return True
return False
@staticmethod
def screen_dimensions():
""" Retrieve total screen dimensions. """
left = win32api.GetSystemMetrics(win32con.SM_XVIRTUALSCREEN)
top = win32api.GetSystemMetrics(win32con.SM_YVIRTUALSCREEN)
height = win32api.GetSystemMetrics(win32con.SM_CYVIRTUALSCREEN)
width = win32api.GetSystemMetrics(win32con.SM_CXVIRTUALSCREEN)
return left,top,height,width
@property
def fps(self):
return int(1 / self._time_average) * (self._time_average > 0)
@property
def region(self):
return self._region
@property
def size(self):
return self._region.width,self._region.height
@region.setter
def region(self,value):
if value is None:
self._region = self.__region(*self.screen_dimensions())
else:
assert len(value) == 4,f"Region requires 4 input,x,y of left top,and x,y of right bottom."
left,x2,y2 = value
width = x2 - left + 1
height = y2 - top + 1
self._region = self.__region(*list(map(int,(left,width,height))))
def screenshot(self,color=None):
"""
Takes a part of the screen,defined by the region.
:param color: cv2.COLOR_....2...
Converts the created BGRA image to the requested image output.
:return: np.ndarray
An image of the region in BGRA values.
"""
left,height = self._region
hwindc = win32gui.GetWindowDC(self.hwin)
srcdc = win32ui.CreateDCFromHandle(hwindc)
memdc = srcdc.CreateCompatibleDC()
bmp = win32ui.CreateBitmap()
bmp.CreateCompatibleBitmap(srcdc,height)
memdc.SelectObject(bmp)
memdc.BitBlt((0,0),(width,height),srcdc,top),win32con.SRCCOPY)
signed_ints_array = bmp.GetBitmapBits(True)
img = np.frombuffer(signed_ints_array,dtype='uint8')
img.shape = (height,4)
srcdc.DeleteDC()
memdc.DeleteDC()
win32gui.ReleaseDC(self.hwin,hwindc)
win32gui.DeleteObject(bmp.GetHandle())
# This makes sure that the FPS are taken in comparison to screenshots rates and vary only slightly.
self._time_taken,self._time_start = time.time() - self._time_start,time.time()
self._time_average = self._time_average * 0.95 + self._time_taken * 0.05
if color is not None:
return cv2.cvtColor(img,color)
return img
def show(self,screenshot=None):
""" Displays an image to the screen. """
image = screenshot if screenshot is not None else self.screenshot()
cv2.imshow('Screenshot',image)
if cv2.waitKey(1) & 0xff == ord('q'):
raise StopIteration
return image
def close(self):
""" Needs to be called before exiting when `show` is used,otherwise an error will occur. """
cv2.destroyWindow('Screenshot')
def scale(self,src: np.ndarray,size: tuple):
return cv2.resize(src,size,interpolation=cv2.INTER_LINEAR_EXACT)
def save(self,path,screenshot=None):
""" Store the current screenshot in the provided path. Full path,with img name is required.) """
image = screenshot if screenshot is not None else self.screenshot
cv2.imwrite(filename=path,img=image)
if __name__ == '__main__':
# Example usage when displaying.
with ScreenCapture((0,1920,1080)) as capture:
for _ in range(100):
capture.show()
print(f"\rCapture framerate: {capture.fps}",end='')
# Example usage as generator.
start_time = time.perf_counter()
for frame,screenshot in enumerate(ScreenCapture((0,1080)),start=1):
print(f"\rFPS: {frame / (time.perf_counter() - start_time):3.0f}",end='')
编辑
我注意到窗口 show 函数中的一些小错误，以及 self.screenshot 和 __getitem__ 方法中的 __next__ 调用。这些都已经解决了。
在使用 ScreenCapture 作为上下文管理器的示例旁边，我添加了一个使用它作为生成器的示例。