implemented getting stream lengths

coub-dl.py

@@ -1,15 +1,44 @@
-from subprocess import call, check_output, STDOUT
+from subprocess import call, Popen, PIPE
+from os import listdir
 from re import match
 from sys import argv
 
+
+
+def getCmdStdErr(command):
+    process = Popen(command, stderr=PIPE, stdout=PIPE)
+    out, err = process.communicate()
+    return err
+
+def getDuration(ffprobe_output):
+    durationPattern = r'.*Duration:\s(.+),\sstart.*'
+    regex = match(durationPattern, str(ffprobe_output))
+    duration = regex.groups()[0] if regex else None
+    if not duration:
+        raise ValueError('Cannot process ffprobe output!')
+    return duration
+
+
 argv.append('https://coub.com/view/aeeuu')
 
 AUDIO_FILE = 'audio'
 VIDEO_FILE = 'video'
-URL = argv[1] if len(argv) > 0 else ''
+URL = argv[1] if len(argv) > 0 else ''  # youtube-dl error message will be shown if ''
 
 call(('/usr/bin/env', 'youtube-dl', '--extract-audio',
                                     '--output',         '{}.%(ext)s'.format(AUDIO_FILE),
                                     URL))
 call(('/usr/bin/env', 'youtube-dl', '--output',         '{}.%(ext)s'.format(VIDEO_FILE),
                                     URL))
+
+for file in listdir():
+    if match('^{}.*'.format(AUDIO_FILE), file):
+        AUDIO_FILE = file
+    if match('^{}.*'.format(VIDEO_FILE), file):
+        VIDEO_FILE = file
+
+audioLen = getDuration(getCmdStdErr(('/usr/bin/env', 'ffprobe', AUDIO_FILE)))
+videoLen = getDuration(getCmdStdErr(('/usr/bin/env', 'ffprobe', VIDEO_FILE)))
+
+print(audioLen)
+print(videoLen)