[naver] Add support for multi track videos

[ubless607]

C:\rtmp>youtube-dl --verbose http://tvcast.naver.com/v/201958
[debug] System config: []
[debug] User config: []
[debug] Command-line args: ['--verbose', 'http://tvcast.naver.com/v/201958']
[debug] Encodings: locale cp949, fs mbcs, out cp949, pref cp949
[debug] youtube-dl version 2014.09.06
[debug] Python version 2.7.8 - Windows-7-6.1.7601-SP1
[debug] Proxy map: {}
[Naver] 201958: Downloading webpage
ERROR: couldn't extract vid and key; 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 "youtube_dl\YoutubeDL.pyo", line 523, in extract_info
  File "youtube_dl\extractor\common.pyo", line 178, in extract
  File "youtube_dl\extractor\naver.pyo", line 34, in _real_extract
ExtractorError: couldn't extract vid and key; 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.

[ubless607]

Looks like it is a "MULTI TRACK", others work fine

[ubless607]

@phihag @jaimeMF Help me!!

[mpenkov]

@ubless607 Works fine here:

$ youtube-dl --verbose http://tvcast.naver.com/v/201958
[debug] System config: []
[debug] User config: []
[debug] Custom config: []
[debug] Command-line args: ['--verbose', 'http://tvcast.naver.com/v/201958']
[debug] Encodings: locale UTF-8, fs utf-8, out utf-8, pref UTF-8
[debug] youtube-dl version 2018.03.14
[debug] Python version 3.6.5 (CPython) - Linux-4.15.0-32-generic-x86_64-with-Ubuntu-18.04-bionic
[debug] exe versions: ffmpeg 3.4.2-2, ffprobe 3.4.2-2, phantomjs 2.1.1, rtmpdump 2.4
[debug] Proxy map: {}
[Naver] 201958: Downloading webpage
[Naver] 201958: Downloading JSON metadata
[debug] Default format spec: bestvideo+bestaudio/best
[debug] Invoking downloader on 'http://g-vod-naver.pstatic.net/navertv/global/read/TVCAST_2014_09_04_2/03100423811353EE7DC38918730A17A3B45_muploader_n_720P_1280_2048_192_B.mp4?__gda__=1534742689_3ac4f9068cfdfd66d5f75a2ac41d3d9d'
[download] Destination: [멀티트랙] '믹스앤매치' 티저 영상, 그들만의 시사회-201958.mp4
[download] 100% of 37.15MiB in 00:05

Can you please confirm?