YouTube - "unable to extract categories"

[Overand]

Link: https://www.youtube.com/watch?v=tu-YAMiS5wA
Version: 2014.12.06.01 (Arch Linux x64)

$ youtube-dl -f bestvideo+bestaudio https://www.youtube.com/watch?v=tu-YAMiS5wA
[youtube] tu-YAMiS5wA: Downloading webpage
[youtube] tu-YAMiS5wA: Extracting video information
WARNING: unable to extract categories; please report this issue on http://yt-dl.org/bug
[youtube] tu-YAMiS5wA: Downloading DASH manifest
[download] Destination: 1981 Nadia Tour gymnastics Paul Hunt comedy uneven bars-tu-YAMiS5wA.f243.webm
[download] 100% of 3.56MiB in 00:01
[download] Destination: 1981 Nadia Tour gymnastics Paul Hunt comedy uneven bars-tu-YAMiS5wA.f141.m4a
[download] 100% of 3.03MiB in 00:01
[ffmpeg] Merging formats into "1981 Nadia Tour gymnastics Paul Hunt comedy uneven bars-tu-YAMiS5wA.webm"
ERROR: Could not write header for output file #0 (incorrect codec parameters ?): Invalid argument

If it's relevant: ffmpeg version 2.4.3 Copyright (c) 2000-2014 the FFmpeg developers
built on Nov 2 2014 09:16:45 with gcc 4.9.1 (GCC) 20140903 (prerelease)

[jaimeMF]

Duplicate of #3610, until it's fixed you can merge a mp4 dash video: youtube-dl 'https://www.youtube.com/watch?v=tu-YAMiS5wA' -f 133+bestaudio

For future reports, please post the full output when you run the command with the --verbose option.

[Overand]

I'd done this to report the "unable to extract categories" issue (not the stream merge), but it appears that's not a problem with this video on 2014.12.17.1 - whoops! Thanks for the attention, regardless. And that bug looks like a hassle! I'll dig a bit but I doubt I'll be able to submit a meaningfull patch before someone else does.

[jaimeMF]

To be honest, when I first read the report I only noticed the unable to extract categories:) (which was fixed with 624dceb, some videos don't have any categories listed in their webpage).
If you write a fix, we'll happily review it.