ERROR: Error in output template: unsupported format character

[pricejn2]

Usage of % symbols in the output throw errors since they are being read as output templates. Is there a better check that could be added since all output templates utilize the form %(TEMPLATE)s?

youtube-dl --verbose 'https://soundcloud.com/esteban-chachalo-dj/mixer-al-100-original-in-the' -o 'MIXER AL 100%Original in the mix - ( Esteban Chachalo dJ ) DEMO.%(ext)s'
[debug] System config: []
[debug] User config: []
[debug] Command-line args: ['--verbose', 'https://soundcloud.com/esteban-chachalo-dj/mixer-al-100-original-in-the', '-o', 'MIXER AL 100%Original in the mix - ( Esteban Chachalo dJ ) DEMO.%(ext)s']
[debug] Encodings: locale UTF-8, fs UTF-8, out UTF-8, pref UTF-8
[debug] youtube-dl version 2015.02.19.3
[debug] Python version 2.7.3 - Linux-3.14.32-xxxx-grs-ipv6-64-x86_64-with-Debian-7
[debug] exe versions: avconv 1.2.12, avprobe 1.2.12, ffmpeg 1.2.12, ffprobe 1.2.12, rtmpdump 2.4
[debug] Proxy map: {}
[soundcloud] esteban-chachalo-dj/mixer-al-100-original-in-the: Resolving id
[soundcloud] esteban-chachalo-dj/mixer-al-100-original-in-the: Downloading info JSON
[soundcloud] 105246408: Downloading track url
ERROR: Error in output template: unsupported format character 'O' (0x4f) at index 13 (encoding: 'UTF-8')
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/youtube_dl/YoutubeDL.py", line 562, in prepare_filename
    filename = tmpl % template_dict
ValueError: unsupported format character 'O' (0x4f) at index 13

[phihag]

Not all output templates use the form %(TEMPLATE)s, although the documentation heavily favors them. Why are you specifying your own title in the first place instead of just -o "%(title)s.%(ext)s"?

In any case, if you are into setting your own title, simply double all percent signs in it.

[pricejn2]

Thanks for the quick response. I didn't see any other bugs on this particular issue so wanted to at least have it out there.

Manually specifying the title can be preferable in some use cases, but not worth re-inventing the wheel for.

Double %% works as expected. Thanks!

[snarfed]

i see this occasionally too, with 2016.7.17, in a python webapp that uses youtube-dl as a library, http://huffduff-video.snarfed.org/. example video url: https://www.oreilly.com/ideas/applications-of-ai-technologies-peter-norvig-in-conversation-with-tim-oreilly

the app uses 'outtmpl': '/tmp/%(webpage_url).240s' in the options dict that it passes to download(). code is here, full stack trace below.

Traceback (most recent call last):
  File "/var/www/cgi-bin/app.py", line 142, in run
    youtube_dl.YoutubeDL(options).download([url])
  File "/usr/local/lib/python2.6/site-packages/youtube_dl/YoutubeDL.py", line 1775, in download
    url, force_generic_extractor=self.params.get('force_generic_extractor', False))
  File "/usr/local/lib/python2.6/site-packages/youtube_dl/YoutubeDL.py", line 693, in extract_info
    return self.process_ie_result(ie_result, download, extra_info)
  File "/usr/local/lib/python2.6/site-packages/youtube_dl/YoutubeDL.py", line 746, in process_ie_result
    extra_info=extra_info)
  File "/usr/local/lib/python2.6/site-packages/youtube_dl/YoutubeDL.py", line 693, in extract_info
    return self.process_ie_result(ie_result, download, extra_info)
  File "/usr/local/lib/python2.6/site-packages/youtube_dl/YoutubeDL.py", line 739, in process_ie_result
    return self.process_video_result(ie_result, download=download)
  File "/usr/local/lib/python2.6/site-packages/youtube_dl/YoutubeDL.py", line 1421, in process_video_result
    self.process_info(new_info)
  File "/usr/local/lib/python2.6/site-packages/youtube_dl/YoutubeDL.py", line 1499, in process_info
    info_dict['_filename'] = filename = self.prepare_filename(info_dict)
  File "/usr/local/lib/python2.6/site-packages/youtube_dl/YoutubeDL.py", line 605, in prepare_filename
    self.report_error('Error in output template: ' + str(err) + ' (encoding: ' + repr(preferredencoding()) + ')')
  File "/usr/local/lib/python2.6/site-packages/youtube_dl/YoutubeDL.py", line 556, in report_error
    self.trouble(error_message, tb)
  File "/usr/local/lib/python2.6/site-packages/youtube_dl/YoutubeDL.py", line 526, in trouble
    raise DownloadError(message, exc_info)
DownloadError: ERROR: Error in output template: unsupported format character 'B' (0x42) at index 53 (encoding: 'ANSI_X3.4-1968')

[dstftw]

/tmp/%(webpage_url).240s is invalid output template.

[snarfed]

...and yet it works almost all the time. :P

you're right that %(webpage_url)s isn't listed in the --output section of --help, but i need a globally unique string, and it's the best option i found, even though it's undocumented. sigh.

[dstftw]

In any case you override it here therefore it's your responsibility to escape % in filename_prefix.

[dstftw]

I'm not about not being listed. .240s is not guaranteed to work. There is no full support for string formatting operations in output template.

[snarfed]

true, thank you! good points. escaping %s fixed it!

[EngineeredJonas]

Double % did work for me! Thanks.