[npo] Update subtitles url

[andrewalker]

NPO websites changed the domain they used for subtitles, from e.omroep.nl to tt888.omroep.nl.

I have:

• Skimmed through adding new extractor tutorial and youtube-dl coding conventions sections
• Searched the bugtracker for similar pull requests

In order to be accepted and merged into youtube-dl each piece of code must be in public domain or released under Unlicense. Check one of the following options:

• I am the original author of this code and I am willing to release it under Unlicense
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What is the purpose of your pull request?

• Bug fix
• Improvement
• New extractor
• New feature

---

Description of your pull request and other information

I noticed I couldn't download subtitles anymore with the npo extractor. In the browser I noticed the subtitles were there in the video. So I just inspected my network, found out the new URL, tested on youtube-dl, and it worked.

Example before my patch:

$ youtube-dl -v --all-subs http://www.npo.nl/jinek/25-01-2017/KN_1687315
[debug] System config: []
[debug] User config: []
[debug] Custom config: []
[debug] Command-line args: [u'-v', u'--all-subs', u'http://www.npo.nl/jinek/25-01-2017/KN_1687315']
[debug] Encodings: locale UTF-8, fs utf-8, out UTF-8, pref UTF-8
[debug] youtube-dl version 2017.01.02
[debug] Python version 2.7.13 - Darwin-14.5.0-x86_64-i386-64bit
[debug] exe versions: avconv 11.4, avprobe 11.4, ffmpeg 3.2.2, ffprobe 3.2.2
[debug] Proxy map: {}
[npo] KN_1687315: Downloading JSON metadata
[npo] KN_1687315: Downloading token
[npo] KN_1687315: Downloading adaptive JSON
[npo] KN_1687315: Downloading adaptive stream JSON
[npo] KN_1687315: Downloading m3u8 information
[npo] KN_1687315: Downloading h264_bb JSON
[npo] KN_1687315: Downloading h264_bb stream JSON
[npo] KN_1687315: Downloading h264_sb JSON
[npo] KN_1687315: Downloading h264_sb stream JSON
[npo] KN_1687315: Downloading h264_std JSON
[npo] KN_1687315: Downloading h264_std stream JSON
WARNING: Unable to download subtitle for "nl": HTTP Error 410: Gone
[debug] Invoking downloader on u'http://content10c5a.omroep.nl/urishieldv2/l27m14012d8630d8e1b200588cecad000000.a40e9ddd2907e0df3e9a7c4384157669/ceresodi/h264/p/34/10/10/33/std_KN_1687315.m4v?odiredirecturl=%2Fvideo%2Fida%2Fh264_std%2Fbd09e29e238945d34bf619d0a854101d%2F588cecad%2FKN_1687315%2F1%3Ftype%3Djsonp%26callback%3D%3F%26type%3Djson'
[download] Resuming download at byte 402222809
[download] Destination: Jinek - Menno Bentveld, Charles Groenhuijsen, Sarah Thurlings-Heijse, Jules Deelder, Petra Stienen, Connie Palmen en Marcia Luyten-KN_1687315.m4v
[download] 100% of 428.50MiB in 00:05

After my patch:

$ python3.6 -m youtube_dl --verbose --all-subs 'http://www.npo.nl/jinek/25-01-2017/KN_1687315' 
[debug] System config: []
[debug] User config: []
[debug] Custom config: []
[debug] Command-line args: ['--verbose', '--all-subs', 'http://www.npo.nl/jinek/25-01-2017/KN_1687315']
[debug] Encodings: locale UTF-8, fs utf-8, out UTF-8, pref UTF-8
[debug] youtube-dl version 2017.01.28
[debug] Git HEAD: 47242d1
[debug] Python version 3.6.0 - Darwin-14.5.0-x86_64-i386-64bit
[debug] exe versions: avconv 11.4, avprobe 11.4, ffmpeg 3.2.2, ffprobe 3.2.2
[debug] Proxy map: {}
[npo] KN_1687315: Downloading JSON metadata
[npo] KN_1687315: Downloading token
[npo] KN_1687315: Downloading adaptive JSON
[npo] KN_1687315: Downloading adaptive stream JSON
[npo] KN_1687315: Downloading m3u8 information
[npo] KN_1687315: Downloading h264_bb JSON
[npo] KN_1687315: Downloading h264_bb stream JSON
[npo] KN_1687315: Downloading h264_sb JSON
[npo] KN_1687315: Downloading h264_sb stream JSON
[npo] KN_1687315: Downloading h264_std JSON
[npo] KN_1687315: Downloading h264_std stream JSON
[info] Writing video subtitles to: Jinek - Menno Bentveld, Charles Groenhuijsen, Sarah Thurlings-Heijse, Jules Deelder, Petra Stienen, Connie Palmen en Marcia Luyten-KN_1687315.nl.vtt
[debug] Invoking downloader on 'http://content10c5c.omroep.nl/urishieldv2/l27m04f15e8e1f0c22b700588ced14000000.7cac8c4616c3ff91a1f3881319a96b01/ceresodi/h264/p/34/10/10/33/std_KN_1687315.m4v?odiredirecturl=%2Fvideo%2Fida%2Fh264_std%2Ffbee0c0865fcb2d2920f31a0bda9d371%2F588ced14%2FKN_1687315%2F1%3Ftype%3Djsonp%26callback%3D%3F%26type%3Djson'
[download] Destination: Jinek - Menno Bentveld, Charles Groenhuijsen, Sarah Thurlings-Heijse, Jules Deelder, Petra Stienen, Connie Palmen en Marcia Luyten-KN_1687315.m4v
[download] 100% of 428.50MiB in 00:43

For a simpler example, with curl, with the old URL:

$ curl -v 'http://e.omroep.nl/tt888/KN_1687315' >/dev/null
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0*   Trying 145.58.33.91...
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0* Connected to e.omroep.nl (145.58.33.91) port 80 (#0)
> GET /tt888/KN_1687315 HTTP/1.1
> Host: e.omroep.nl
> User-Agent: curl/7.43.0
> Accept: */*
>
< HTTP/1.1 410 Gone
< Date: Sat, 28 Jan 2017 19:19:20 GMT
< Server: Apache
< Content-Length: 311
< Content-Type: text/html; charset=iso-8859-1
<
{ [311 bytes data]
100   311  100   311    0     0   3802      0 --:--:-- --:--:-- --:--:--  3792
* Connection #0 to host e.omroep.nl left intact

With the URL I just introduced:

$ curl -v 'http://tt888.omroep.nl/tt888/KN_1687315' >/dev/null
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0*   Trying 145.58.33.96...
* Connected to tt888.omroep.nl (145.58.33.96) port 80 (#0)
> GET /tt888/KN_1687315 HTTP/1.1
> Host: tt888.omroep.nl
> User-Agent: curl/7.43.0
> Accept: */*
>
< HTTP/1.1 200 OK
< Date: Sat, 28 Jan 2017 19:20:15 GMT
< Server: Apache
< Cache-Control: private, max-age=300, must-revalidate
< Expires: Sat, 28 Jan 2017 19:25:15 GMT
< Access-Control-Allow-Origin: *
< Last-Modified: Sat, 28 Jan 2017 19:20:15 GMT
< X-Node: tab-as56
< Transfer-Encoding: chunked
< Content-Type: text/vtt
<
{ [2566 bytes data]
100 59562    0 59562    0     0   665k      0 --:--:-- --:--:-- --:--:--  668k
* Connection #0 to host tt888.omroep.nl left intact