基于Python+OpenCV制作屏幕錄制工具

更新時(shí)間：2022年04月22日 12:20:58 作者：程序員小二

這篇文章主要介紹了如何利用Python?OpenCV實(shí)現(xiàn)屏幕錄制工具的制作，文中的示例代碼講解詳細(xì)，對(duì)我們的學(xué)習(xí)和工作有一定的價(jià)值，感興趣的可以學(xué)習(xí)一下

應(yīng)用平臺(tái)

windows 10
python 3.7

屏幕錄制部分

屏幕錄制可以簡(jiǎn)單地理解為將屏幕快照以動(dòng)圖的形式播放，這里我選用PIL下的ImageGrab來(lái)截取屏幕畫(huà)面，首先

pip install Pillow

之后需要將截取到的快照數(shù)組合成為視頻，使用cv2模塊

pip install opencv-python

ImageGrab類不能直接存儲(chǔ)為視頻，使用numpy模塊進(jìn)行數(shù)組化，再通過(guò)cv2.COLOR_BGR2RGB轉(zhuǎn)換為cv2色彩通道。

pip install numpy

屏幕錄制主要代碼：

import?numpy?as?np
from?PIL?import?ImageGrab
import?cv2

im?=?ImageGrab.grab()
width,?high?=?im.size??#?獲取屏幕的寬和高
fourcc?=?cv2.VideoWriter_fourcc(*'I420')??#?設(shè)置視頻編碼格式
fps?=?15??#?設(shè)置幀率
video?=?cv2.VideoWriter('test.avi',?fourcc,?fps,?(width,?high))
while?True:??#?開(kāi)始錄制
????im?=?ImageGrab.grab()
????im_cv?=?cv2.cvtColor(np.array(im),?cv2.COLOR_BGR2RGB)
????#?圖像寫(xiě)入
????video.write(im_cv)
????if?xx:??#?當(dāng)某某條件滿足中斷循環(huán)
????????break
video.release()??#?釋放緩存，持久化視頻

測(cè)試運(yùn)行可以保存屏幕快照為視頻，但操作起來(lái)不優(yōu)雅，也不利于后續(xù)的操作。

封裝成類，繼承線程父類，方便使用鍵盤(pán)來(lái)控制視頻錄制的結(jié)束。

from?threading?import?Thread

class?ScreenshotVideo(Thread):

????def?__init__(self):
?????"""初始化參數(shù)"""
????????super().__init__()

詳細(xì)代碼將在文末給出。

計(jì)算視頻最優(yōu)fps及使用numpy計(jì)算中間幀數(shù)組

實(shí)際操作中視頻錄制在不同電腦中會(huì)出現(xiàn)不一樣的幀率，導(dǎo)致視頻播放或快或慢，需要根據(jù)不同的電腦計(jì)算出相應(yīng)的最優(yōu)fps值。

def?video_best_fps(self,?path):
????"""獲取電腦錄制視頻的最優(yōu)幀率"""
????video?=?cv2.VideoCapture(path)??#?讀取視頻
????fps?=?video.get(cv2.CAP_PROP_FPS)??#?獲取當(dāng)前視頻的幀率
????count?=?video.get(cv2.CAP_PROP_FRAME_COUNT)??#?獲取視頻幀數(shù)，即該視頻有多少幅畫(huà)面
????self.best_fps?=?int(fps?*?((int(count)?/?fps)?/?self.spend_time))???#?計(jì)算播放時(shí)間與錄制時(shí)間對(duì)比得到最優(yōu)幀率
????video.release()

再調(diào)整幀率參數(shù)進(jìn)行錄制視頻就減弱了視頻播放太快或者太慢。也可以給視頻增加幀數(shù)從而延長(zhǎng)播放時(shí)間，這里我采用一種很簡(jiǎn)單的方法增加視頻幀，僅供參考。

from?numba?import?jit

#?使用numpy計(jì)算相鄰兩幀圖像且更接近于后一幀的圖像
#?調(diào)用jit方法加速數(shù)組計(jì)算
@jit(nopython=True)
def?average_n(x,?y):
????"""Numpy計(jì)算趨近值"""
????return?((x?+?y?+?y)?//?3).astype(x.dtype)

該方法僅針對(duì)于設(shè)置的fps比最優(yōu)fps要高時(shí)，處理后的視頻觀感，視頻還是較為急促，但是細(xì)節(jié)幀增多，所以播放時(shí)長(zhǎng)會(huì)比未處理前的要長(zhǎng)，略有殘影。

使用pynput監(jiān)聽(tīng)鍵盤(pán)按鍵

在視頻錄制中，并不知道視頻何時(shí)結(jié)束，所以用while循環(huán)包裹錄制代碼，但也不可能讓代碼無(wú)休止的運(yùn)行下去，在此使用監(jiān)聽(tīng)鍵盤(pán)模塊來(lái)中斷錄制代碼的運(yùn)行。

from?pynput?import?keyboard??#?pip?install?pynput

def?hotkey(self):
????"""熱鍵監(jiān)聽(tīng)"""
????with?keyboard.Listener(on_press=self.on_press)?as?listener:
????????listener.join()

def?on_press(self,?key):
????try:
????????if?key.char?==?'t':??#?錄屏結(jié)束，保存視頻
????????????self.flag?=?True
????????elif?key.char?==?'k':??#?錄屏中止，刪除文件
????????????self.flag?=?True
????????????self.kill?=?True
????except?Exception?as?e:
????????print(e)

按下鍵盤(pán)“T”鍵時(shí)，結(jié)束錄制，保存視頻。“K”鍵則是停止錄制，刪除緩存文件。

如何保存MP4格式視頻

視頻編碼格式應(yīng)該為('a', 'v', 'c', '1')，文件后綴為'.mp4'，在錄制前先去https://github.com/cisco/openh264/releases下下載對(duì)應(yīng)平臺(tái)的dll.bz2文件，將壓縮包解壓放在項(xiàng)目文件夾下。再運(yùn)行代碼，成功會(huì)出現(xiàn)一行編碼說(shuō)明：

OpenH264 Video Codec provided by Cisco Systems, Inc.

源碼

本文實(shí)現(xiàn)的源碼如下：

import?time
from?PIL?import?ImageGrab
import?cv2
from?pathlib?import?Path
import?numpy?as?np
from?numba?import?jit
from?pynput?import?keyboard
from?threading?import?Thread


@jit(nopython=True)
def?average_n(x,?y):
????"""Numpy計(jì)算趨近值"""
????return?((x?+?y?+?y)?//?3).astype(x.dtype)


class?ScreenshotVideo(Thread):

????def?__init__(self,?width,?high,?path='',?fps=15):
????????"""初始化參數(shù)"""
????????super().__init__()
????????self.save_file?=?path
????????self.best_fps?=?fps
????????self.fps?=?fps
????????self.width?=?width
????????self.high?=?high
????????self.spend_time?=?1
????????self.flag?=?False
????????self.kill?=?False
????????self.video?=?None

????def?__call__(self,?path):
????????"""重載視頻路徑，便于類的二次調(diào)用"""
????????self.save_file?=?Path(path)
????????self.video?=?self.init_videowriter(self.save_file)

????@staticmethod
????def?screenshot():
????????"""靜態(tài)方法，屏幕截圖，并轉(zhuǎn)換為np.array數(shù)組"""
????????return?np.array(ImageGrab.grab())

????@staticmethod
????def?get_fourcc(name):
????????"""視頻編碼字典"""
????????fourcc_maps?=?{'.avi':?'I420',
???????????????????????'.m4v':?'mp4v',
???????????????????????'.mp4':?'avc1',
???????????????????????'.ogv':?'THEO',
???????????????????????'.flv':?'FLV1',
???????????????????????}
????????return?fourcc_maps.get(name)

????def?init_videowriter(self,?path):
????????"""獲取視頻編碼并新建視頻文件"""
????????if?not?path:
????????????raise?Exception('視頻路徑未設(shè)置，請(qǐng)?jiān)O(shè)置\nvideo?=?ScreenshotVideo(fps,width,high)\nvideo?=?video(video_path)')
????????path?=?Path(path)?if?isinstance(path,?str)?else?path
????????fourcc?=?cv2.VideoWriter_fourcc(*self.get_fourcc(path.suffix))
????????return?cv2.VideoWriter(path.as_posix(),?fourcc,?self.fps,?(self.width,?self.high))

????def?video_record_doing(self,?img):
????????"""將BGR數(shù)組轉(zhuǎn)換為RGB數(shù)組"""
????????im_cv?=?cv2.cvtColor(img,?cv2.COLOR_BGR2RGB)
????????self.video.write(im_cv)

????def?video_record_end(self):
????????"""錄制結(jié)束，根據(jù)條件判斷文件是否保存"""
????????self.video.release()
????????cv2.destroyAllWindows()
????????if?self.save_file?and?self.kill:
????????????Path(self.save_file).unlink()

????def?video_best_fps(self,?path):
????????"""獲取電腦錄制視頻的最優(yōu)幀率"""
????????video?=?cv2.VideoCapture(path)
????????fps?=?video.get(cv2.CAP_PROP_FPS)
????????count?=?video.get(cv2.CAP_PROP_FRAME_COUNT)
????????self.best_fps?=?int(fps?*?((int(count)?/?fps)?/?self.spend_time))
????????video.release()

????def?pre_video_record(self):
????????"""預(yù)錄制，以獲取最佳fps值"""
????????self.video?=?self.init_videowriter('test.mp4')
????????start_time?=?time.time()
????????for?_?in?range(10):
????????????im?=?self.screenshot()
????????????self.video_record_doing(im)
????????self.spend_time?=?round(time.time()?-?start_time,?4)
????????self.video_record_end()
????????time.sleep(2)
????????self.video_best_fps('test.mp4')
????????Path('test.mp4').unlink()

????def?insert_frame_array(self,?frame_list):
????????"""Numpy增強(qiáng)截圖信息"""
????????fps_n?=?round(self.fps?/?self.best_fps)
????????if?fps_n?<=?0:
????????????return?frame_list
????????times?=?int(np.log2(fps_n))??#?倍率
????????for?_?in?range(times):
????????????frame_list2?=?map(average_n,?[frame_list[0]]?+?frame_list[:-1],?frame_list)
????????????frame_list?=?[[x,?y]?for?x,?y?in?zip(frame_list2,?frame_list)]
????????????frame_list?=?[j?for?i?in?frame_list?for?j?in?i]
????????return?frame_list

????def?frame2video_run(self):
????????"""使用opencv將連續(xù)型截圖轉(zhuǎn)換為視頻"""
????????self.video?=?self.init_videowriter(self.save_file)
????????start_time?=?time.time()
????????frame_list?=?[]
????????while?True:
????????????frame_list.append(self.screenshot())
????????????if?self.flag:
????????????????break
????????self.spend_time?=?round(time.time()?-?start_time,?4)
????????if?not?self.kill:??#?視頻錄制不被終止將逐幀處理圖像
????????????frame_list?=?self.insert_frame_array(frame_list)
????????????for?im?in?frame_list:
????????????????self.video_record_doing(im)
????????self.video_record_end()

????def?hotkey(self):
????????"""熱鍵監(jiān)聽(tīng)"""
????????with?keyboard.Listener(on_press=self.on_press)?as?listener:
????????????listener.join()

????def?on_press(self,?key):
????????try:
????????????if?key.char?==?'t':??#?錄屏結(jié)束，保存視頻
????????????????self.flag?=?True
????????????elif?key.char?==?'k':??#?錄屏中止，刪除文件
????????????????self.flag?=?True
????????????????self.kill?=?True
????????except?Exception?as?e:
????????????print(e)

????def?run(self):
????????#?運(yùn)行函數(shù)
????????#?設(shè)置守護(hù)線程
????????Thread(target=self.hotkey,?daemon=True).start()
????????#?運(yùn)行截圖函數(shù)
????????self.frame2video_run()


screen?=?ImageGrab.grab()
width,?high?=?screen.size
video?=?ScreenshotVideo(width,?high,?fps=60)
video.pre_video_record()??#?預(yù)錄制獲取最優(yōu)fps
video('test1.mp4')
video.run()