Sonarr subs extraction

#!/usr/bin/env python
#

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### SONARR POST-PROCESSING SCRIPT                                                               ###
#                                                                                               ###
# Script to rip srt subtitles out of .mkv files                                                 ###
#                                                                                               ###
# Used to extract English and Dutch subtitles.                                                  ###
# To specify the languages extracted, you can alter the values for                              ###
# StreamLang1Ids, StreamLang2Ids and Ext(.language tag.srt)                                     ###
#                                                                                               ###
# Processing files which contain multiple subtitle streams for the same language will only      ###
# result in the last stream being decrypted. <-- Looking for better behaviour.                  ###
# This is often the case with WEB-DL.                                                           ###
#                                                                                               ###
#                       !!! Make sure to alter your log file location !!!                       ###
#                           !!! Make sure to alter your ffmpeg path !!!                         ###
#                                                                                               ###
# Credits to BenV for the basecode                                                              ###
#                                                                                               ###
# To do:                                                                                        ###
# - Make the overwrite a variable (-y/-n)                                                       ###
# - Make language tag / Ext input a variable .nl.srt                                            ###
# - Add escape for additional languages with fake language tag                                  ###
#                                                                                               ###
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#                                                                                               ###
#                                                                                               ###
###################################################################################################


from re import findall
from subprocess import Popen, PIPE
from datetime import datetime
from os import environ
from sys import argv

    # Get the video file name from the environment variables
filePath = environ.get('sonarr_episodefile_path')

    #Enable for troubleshooting. Enables parsing arguments to variable manually.
    #Example command: python scriptname.py /volume1/Sonarr/Series/SeriesE01.mkv
#filePath = argv[1]

    #Extracting the filename and extension
fileName = filePath.split('/')[-1]

    #Logfile location and open it unbuffered so you can read it during execution.
fp = open('/volume1/Sonarr/postprocess.log', 'a',0)

    # If the ffmpeg excutable is in the path use this
#ffmpeg = 'D:\\aaa\\ffmpeg.exe'
    # if you want to use an ffmpeg version from the SynoCommunity use this:
ffmpeg = '/volume1/@appstore/ffmpeg/bin/ffmpeg'

    # This list contains possible subtitle stream identifiers for the first preferred language
StreamLang1Ids = ['nl','nld','dut','dutch','qoq','qoq-team']

    # This list contains possible subtitle stream identifiers for the second preferred language
StreamLang2Ids = ['en','eng','english']


    #Timestamp variable for logfile
sttime = datetime.now().strftime('%Y%m%d %H:%M:%S - ')
if not filePath.lower().endswith('.mkv'):
    fp.write(sttime + fileName + ' is not an .mkv file, processing stopped.\n\n')
    fp.close()
    raise SystemExit
else:
    fp.write(sttime + fileName + ' is an .mkv file, processing started.\n')

    # First read the information from the video with ffmpeg.
    # ffmpeg writes this info to the stderr and not to stdout.
Cmd = [ffmpeg,'-i', filePath]
Merge = Popen(Cmd, stdout=PIPE, stderr=PIPE)
    # After the command is prepared we execute it and wait for it to finish with the communicate command
output,err = Merge.communicate()

    # ffmpeg writes to stderr
    # make lines insted of one large buffer
err= err.splitlines()

    # loop through the information lines, find the stream identifiers and count them
NonSubStreamCount = 0
for Line in err:
    if 'Stream #' in Line:
        NonSubStreamCount += 1
            # if it is a subtitle stream, get the stream info
        if 'Subtitle: subrip' in Line:
            NonSubStreamCount -= 1
                # use some regexes to find the stream info
            StreamNum = int(findall(r'\d+\.{0,1}\d*', Line)[1]) - NonSubStreamCount
            StreamLang = findall(r'\((.*?)\)', Line)[0]
                # compose the map identifiers for the ffmpeg command.
            Streamspec = '0:s:' + str(StreamNum)
                # try to identify the language and create the correct file extension belonging to that language.
            Ext = ''
                # First we look to see if it is a sub matching preferred language 1
            for Id in StreamLang1Ids:
                if Id == StreamLang.lower():
                    Ext = '.nl.srt'
                    break
                # If not, we look to see if it is a sub matching preferred language 2
            if not Ext:
                for Id in StreamLang2Ids:
                    if Id == StreamLang.lower():
                        Ext = '.en.srt'
                        break
                # We only process the files is their is a preferred language match
            if Ext:
                OutputFile = filePath[:-4] + Ext
                Cmd =[ffmpeg, '-y', '-loglevel','-32','-i', filePath,'-map',Streamspec,OutputFile]
                Merge = Popen(Cmd, stdout=PIPE, stderr=PIPE)
                sttime = datetime.now().strftime('%Y%m%d_%H:%M:%S - ')
                fp.write(sttime + 'Extracting stream ' + Streamspec + ' language = ' + StreamLang + '\n')
                output,err = Merge.communicate()
                if err:
                    fp.write('Problem extracting subtitle.\n')
                    fp.write(err + '\n')

sttime = datetime.now().strftime('%Y%m%d_%H:%M:%S - ')
fp.write(sttime + 'Processing finished.\n\n')

    # close the logfile and exit back to Sonarr
fp.close()
raise SystemExit