Python 为什么会出现这个错误_Python_Python 3.x

Python 为什么会出现这个错误

python python-3.x

Python 为什么会出现这个错误,python,python-3.x,Python,Python 3.x,我已经编写了这段代码，这样当我输入一些信息时，它就会创建代码，允许我实时流到twitch。代码如下： import time ip = input("Please enter the local IP address: ") port = input("Please enter the port number: ") resolution = input("Please enter the resolution: ") valid_classes = ["ultrafast", "fast",

我已经编写了这段代码，这样当我输入一些信息时，它就会创建代码，允许我实时流到twitch。代码如下：

import time
ip = input("Please enter the local IP address: ")
port = input("Please enter the port number: ")
resolution = input("Please enter the resolution: ")
valid_classes = ["ultrafast", "fast", "medium", "slow"]
while True:
    print('What preset would you like? Choose from ultrafast, fast, medium and slow: ')
    preset1 = input()
    if preset1 not in valid_classes:
        print("Please Enter A Valid Preset All In Lower Case")
        time.sleep(1)
    else:
        fps = input("How many FPS would you like: ")
        valid_service = ["youtube", "twitch"]
        while True:
            print('What service would you like to stream to? Please choose from youtube or twitch: ')
            service = input()
            if service not in valid_service:
                print("Please Enter A Valid Service All In Lower Case")
                time.sleep(1)
            else:
                key = input("Please enter your stream key: ")
                if service == "twitch":
                    fortwitch = ("rtmp://live.justin.tv/app/")+key+("")
                    print("ffmpeg -f mpegts -i 'udp://")+ip+(":")+port+("?fifo_size=1000000&buffer_size=10000000&overrun_nonfatal=1' -vcodec libx264 -s ")+resolution+(" -g:v 40 -qscale:v 2 -threads 4 -preset ")+preset1+(" -b:v 1136k -minrate 1300k -maxrate 1300k  -bufsize 8000k -r ")+fps+(" -acodec libmp3lame -ar 44100 -b:a 64k -f flv ")+fortwitch+("")
                else:
                    print ("ok")

运行代码时，我收到以下错误消息：

Traceback (most recent call last):
  File "/Users/kiancross/Desktop/LIVESTREAM/livestreamoptions.py", line 25, in <module>
    print("ffmpeg -f mpegts -i 'udp://")+ip+(":")+port+("?      fifo_size=1000000&buffer_size=10000000&overrun_nonfatal=1' -vcodec libx264 -s ")+resolution+(" -g:v 40 -qscale:v 2 -threads 4 -preset ")+preset1+(" -b:v 1136k -minrate 1300k -maxrate 1300k  -bufsize 8000k -r ")+fps+(" -acodec libmp3lame -ar 44100 -b:a 64k -f flv ")+fortwitch+("")
TypeError: unsupported operand type(s) for +: 'NoneType' and 'str'

当我运行它时，它只是循环回您希望流到的服务。当它在终端时，它只是说

Traceback (most recent call last):
  File "./livestreamoptions.py", line 8, in <module>
    preset1 = input()
  File "<string>", line 1, in <module>

回溯（最近一次呼叫最后一次）：
文件“/livestreamoptions.py”，第8行，在
预设1=输入（）
文件“”，第1行，在

print（）

None

，您正在尝试向其中添加更多字符串：

print("ffmpeg -f mpegts -i 'udp://")+ip # etc.
# ---------------- print ends here ^

将整个字符串连接移动到

print（）

函数中：

print("ffmpeg -f mpegts -i 'udp://"+ip+":"+port+"?fifo_size=1000000&buffer_size=10000000&overrun_nonfatal=1' -vcodec libx264 -s "+resolution+" -g:v 40 -qscale:v 2 -threads 4 -preset "+preset1+" -b:v 1136k -minrate 1300k -maxrate 1300k  -bufsize 8000k -r "+fps+" -acodec libmp3lame -ar 44100 -b:a 64k -f flv "+fortwitch)

或者更好地使用字符串格式：

print("ffmpeg -f mpegts -i 'udp://{}:{}?fifo_size=1000000&buffer_size=10000000&overrun_nonfatal=1' "
      "-vcodec libx264 -s{} -g:v 40 -qscale:v 2 -threads 4 -preset {} "
      "-b:v 1136k -minrate 1300k -maxrate 1300k  -bufsize 8000k -r {} "
      " -acodec libmp3lame -ar 44100 -b:a 64k -f flv {}".format(
      ip, port, resolution, preset1, fps, fortwitch))

它还有一个额外的优点，就是可读性更强

要实际执行该命令，请使用，但最好使用参数列表：

args = [
    'ffmpeg', '-f', 'mpegts', '-i', 
    'udp://{}:{}?fifo_size=1000000&buffer_size=10000000&overrun_nonfatal=1'.format(ip, port),
    '-vcodec', 'libx264', '-s', resolution, '-g:v', '40', '-qscale:v', '2',
    '-threads', '4', '-preset', preset1, '-b:v', '1136k', '-minrate', '1300k',
    '-maxrate', '1300k', '-bufsize', '8000k', '-r', fps, '-acodec', 'libmp3lame',
    '-ar', '44100', '-b:a', '64k', '-f', 'flv', fortwitch]

subprocess.call(args)

它允许您在

args

列表中将参数作为单独的元素列出，并使用最小的字符串格式。

print（）

None