python-3.x - Python 3.10 中 ffprobe 的困难

Question

我很新
所以这个 getLength 函数将在 python 2.7 中运行良好，但我无法让它在 3.10 中运行。想知道是否有人可以建议可能需要更改的内容，因为我不知所措。当我尝试打印退货时，那里什么都没有。我 95% 确定问题出在 result = subprocess.Popen() 行，但为了完整起见，我包含了整个函数
#function... 返回视频文件的持续时间 HH:MM:SS

def getLength(filename):

   #uses ffprobe to get info about the video file

   result = subprocess.Popen(["ffprobe", filename],

   stdout = subprocess.PIPE, stderr = subprocess.STDOUT)


   #finds the info that has the word "Duration"

   y = [x for x in result.stdout.readlines() if "Duration: " in x]

   #get the location of the "Duration: " phrase

   loc = y[0].find("Duration: ")

   #assuming we find the location of that phrase..

   if loc != -1:

   #cut out everything before and everything more than 10 characters later

   print ( y[0][loc+10:loc+18] )

   return y[0][loc+10:loc+18]

   else:

   #if we don't find anything then set it to be 2 seconds of nothing...

   print ( y[0][loc+10:loc+18] )

   return '00:00:02' 

Answer 1

在 Python 3 中，字符串位于 Unicode format , 和 stdout输出是字节数组。
我们可以使用 x.decode("utf-8") 将字节数组转换为字符串。 :
解析列表可能如下所示:

y = [x.decode("utf-8") for x in result.stdout.readlines() if "Duration: " in x.decode("utf-8")]

完整的代码示例(使用 stderr 而不是 stdout ):

import subprocess

def get_length(filename):
    # Uses FFprobe to get info about the video file
    result = subprocess.Popen(["ffprobe", filename], stderr=subprocess.PIPE)

    # Finds the info that has the word "Duration"
    # Convert bytes array to strings using decode("utf-8")
    y = [x.decode("utf-8") for x in result.stderr.readlines() if "Duration: " in x.decode("utf-8")]

    # Get the location of the "Duration: " phrase
    loc = y[0].find("Duration: ")

    # Assuming we find the location of that phrase..
    if loc != -1:
        # Cut out everything before and everything more than 10 characters later
        print(y[0][loc+10:loc+18])
        return y[0][loc+10:loc+18]
    else:
        # If we don't find anything then set it to be 2 seconds of nothing...
        print(y[0][loc+10:loc+18])
        return '00:00:02' 


res = get_length('BBB.ogv')
print(res)

为了获取 OVG(或 MP4)文件的视频时长，我们可以选择 JSON 格式:

import subprocess as sp
import json

# https://superuser.com/questions/650291/how-to-get-video-duration-in-seconds
data = sp.run(["ffprobe", '-v', 'error', '-select_streams', 'v', '-of', 'default=noprint_wrappers=1:nokey=1', '-show_entries', 'stream=duration', '-of', 'json', 'BBB.ogv'], stdout=sp.PIPE).stdout

dict = json.loads(data)

print(dict['streams'][0]['duration'])