Improve and test ffmpeg version detection

test/test_utils.py

@@ -16,39 +16,40 @@
 import xml.etree.ElementTree
 
 from youtube_dl.utils import (
+    args_to_str,
     clean_html,
     DateRange,
+    detect_exe_version,
     encodeFilename,
+    escape_rfc3986,
+    escape_url,
     find_xpath_attr,
     fix_xml_ampersands,
-    orderedSet,
-    OnDemandPagedList,
     InAdvancePagedList,
+    intlist_to_bytes,
+    js_to_json,
+    limit_length,
+    OnDemandPagedList,
+    orderedSet,
     parse_duration,
+    parse_filesize,
+    parse_iso8601,
     read_batch_urls,
     sanitize_filename,
     shell_quote,
     smuggle_url,
     str_to_int,
+    strip_jsonp,
     struct_unpack,
     timeconvert,
     unescapeHTML,
     unified_strdate,
     unsmuggle_url,
+    uppercase_escape,
     url_basename,
     urlencode_postdata,
-    xpath_with_ns,
-    parse_iso8601,
-    strip_jsonp,
-    uppercase_escape,
-    limit_length,
-    escape_rfc3986,
-    escape_url,
-    js_to_json,
-    intlist_to_bytes,
-    args_to_str,
-    parse_filesize,
     version_tuple,
+    xpath_with_ns,
 )
 
 
@@ -390,5 +391,16 @@ def test_version_tuple(self):
         self.assertEqual(version_tuple('10.23.344'), (10, 23, 344))
         self.assertEqual(version_tuple('10.1-6'), (10, 1, 6))  # avconv style
 
+    def test_detect_exe_version(self):
+        self.assertEqual(detect_exe_version('''ffmpeg version 1.2.1
+built on May 27 2013 08:37:26 with gcc 4.7 (Debian 4.7.3-4)
+configuration: --prefix=/usr --extra-'''), '1.2.1')
+        self.assertEqual(detect_exe_version('''ffmpeg version N-63176-g1fb4685
+built on May 15 2014 22:09:06 with gcc 4.8.2 (GCC)'''), 'N-63176-g1fb4685')
+        self.assertEqual(detect_exe_version('''X server found. dri2 connection failed!
+Trying to open render node...
+Success at /dev/dri/renderD128.
+ffmpeg version 2.4.4 Copyright (c) 2000-2014 the FFmpeg ...'''), '2.4.4')
+
 if __name__ == '__main__':
     unittest.main()

youtube_dl/utils.py

@@ -1262,18 +1262,25 @@ def check_executable(exe, args=[]):
 
 
 def get_exe_version(exe, args=['--version'],
-                    version_re=r'version\s+([0-9._-a-zA-Z]+)',
-                    unrecognized='present'):
+                    version_re=None, unrecognized='present'):
     """ Returns the version of the specified executable,
     or False if the executable is not present """
     try:
-        out, err = subprocess.Popen(
+        out, _ = subprocess.Popen(
             [exe] + args,
             stdout=subprocess.PIPE, stderr=subprocess.STDOUT).communicate()
     except OSError:
         return False
-    firstline = out.partition(b'\n')[0].decode('ascii', 'ignore')
-    m = re.search(version_re, firstline)
+    if isinstance(out, bytes):  # Python 2.x
+        out = out.decode('ascii', 'ignore')
+    return detect_exe_version(out, version_re, unrecognized)
+
+
+def detect_exe_version(output, version_re=None, unrecognized='present'):
+    assert isinstance(output, compat_str)
+    if version_re is None:
+        version_re = r'version\s+([-0-9._a-zA-Z]+)'
+    m = re.search(version_re, output)
     if m:
         return m.group(1)
     else: