ExtractorError: Automatic signature extraction failed

[ghost]

When attempting to run youtube-dl on Fedora 20 x64, I encounter the following error (this is running --verbose as you can see):
youtube-dl -c --verbose https://www.youtube.com/watch?v=MqWJX1jS_c4
[debug] System config: ['--prefer-free-formats']
[debug] User config: []
[debug] Command-line args: ['-c', '--verbose', 'https://www.youtube.com/watch?v=MqWJX1jS_c4']
[debug] Encodings: locale UTF-8, fs UTF-8, out UTF-8, pref UTF-8
[debug] youtube-dl version 2014.07.11.3
[debug] Python version 2.7.5 - Linux-3.15.5-200.fc20.x86_64-x86_64-with-fedora-20-Heisenbug
[debug] Proxy map: {}
[youtube] Setting language
[youtube] MqWJX1jS_c4: Downloading webpage
[youtube] MqWJX1jS_c4: Downloading video info webpage
[youtube] MqWJX1jS_c4: Extracting video information
[youtube] MqWJX1jS_c4: Encrypted signatures detected.
[youtube] encrypted signature length 83 (55.27), itag 43, html5 player en_US-vflkX5nuy/html5player
ERROR: Automatic signature extraction failed: Traceback (most recent call last):
File "/usr/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 877, in _decrypt_signature
video_id, player_url, len(s)
File "/usr/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 352, in _extract_signature_function
player_type = id_m.group('ext')
AttributeError: 'NoneType' object has no attribute 'group'
; please report this issue on https://yt-dl.org/bug . Be sure to call youtube-dl with the --verbose flag and include its complete output. Make sure you are using the latest version; type youtube-dl -U to update.
Traceback (most recent call last):
File "/usr/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 877, in _decrypt_signature
video_id, player_url, len(s)
File "/usr/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 352, in _extract_signature_function
player_type = id_m.group('ext')
AttributeError: 'NoneType' object has no attribute 'group'
Traceback (most recent call last):
File "/usr/bin/youtube-dl/youtube_dl/YoutubeDL.py", line 516, in extract_info
ie_result = ie.extract(url)
File "/usr/bin/youtube-dl/youtube_dl/extractor/common.py", line 168, in extract
return self._real_extract(url)
File "/usr/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 1249, in _real_extract
encrypted_sig, video_id, player_url, age_gate)
File "/usr/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 887, in _decrypt_signature
u'Automatic signature extraction failed: ' + tb, cause=e)
ExtractorError: Automatic signature extraction failed: Traceback (most recent call last):
File "/usr/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 877, in _decrypt_signature
video_id, player_url, len(s)
File "/usr/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 352, in _extract_signature_function
player_type = id_m.group('ext')
AttributeError: 'NoneType' object has no attribute 'group'

It makes no difference whether the URL contains https:// or http://

youtube-dl -U does nothing

[gregrich91]

I'm getting this problem too. Is this because YT is changing from day to day? It was working last night....

[phihag]

Thank you for the report. This has been fixed in the newest version, 2014.07.25. Type sudo youtube-dl -U to update.

@gregrich91 The YouTube html5 player signature obfuscation (which is not used/required for all videos, but for some, typically very popular) changes daily. youtube-dl interprets this player just like a webbrowser, but our interpreter was not yet prepared to deal with the full range of code. Since YouTube changed the player generation recently, this means that quite a few bugs or missing features in our interpreter were uncovered. It's likely that this will settle down soon.