使用python-vlc从youtube视频中获取屏幕截图

Question

使用 vlc python API，我想浏览一下 youtube 视频，每 10 秒拍摄一次快照。

使用我目前的方法，我遇到了问题，因为我必须依赖于播放器更新其显示图像的速度。这种情况发生的速度是不可预测的。我认为，最好的情况是在玩家显示新图像时触发事件。然后我可以对此做出反应，而不必对time.sleep()感到模糊.

目前，我等到收到带有时间戳的视频缓冲区包，该时间戳保证播放器可以在所需的时间戳显示图像。

首先，我实例化播放器并等待它出现在屏幕上(需要一个事件(。然后循环从截图开始。

import pafy
import vlc
import os
import time
url = "https://www.youtube.com/watch?v=bMt47wvK6u0"
video = pafy.new(url)
best = video.getbest()
playurl = best.url
skipTime = 1000*10*10 # milliseconds

directory = "images/"
prefix = str.split(url, "=")[1] + "_" # get video ID, end of url
harvesting = False
waitForBuffer = False
recordTime = 0
def callbackBuffering(arg):
global waitForBuffer
global harvesting
if(recordTime + skipTime < arg.u.new_time and harvesting):
waitForBuffer = False
try:
os.mkdir("images")
except:
print("directory exists")    

Instance = vlc.Instance()
player = Instance.media_player_new()
eventManager = player.event_manager()
eventManager.event_attach(vlc.EventType.MediaPlayerBuffering, callback = callbackBuffering)

Media = Instance.media_new(playurl)
Media.get_mrl()
player.set_media(Media)
player.play()
time.sleep(5) # wait till the window appears
player.pause()
images = 0
harvesting = True
while(player.get_time() < player.get_length()):
waitForBuffer = True
path = directory + prefix + str(player.get_time() )
print("image will be taken at " + str(player.get_time() ) + "ms at path "+ path )   
time.sleep(0.5)
recordTime = player.get_time()
player.video_take_snapshot(0, directory + prefix + str(recordTime) ,i_width=player.video_get_width(), i_height=player.video_get_height())
player.set_time(recordTime+skipTime)

while(waitForBuffer):
print("waiting for buffering")
time.sleep(0.1)

Answer 1

尝试EventType.MediaPlayerPositionChanged或EventType.MediaPlayerTimeChanged它们似乎都基于每秒计数工作。
他们还很高兴地处理等待视频加载的时间，因为在显示某些内容之前，时间和位置都不会改变