[PornHub] Subtitles support

[hman9299]

• I've verified and I assure that I'm running youtube-dl 2018.07.04

Before submitting an issue make sure you have:

• At least skimmed through the README, most notably the FAQ and BUGS sections
• Searched the bugtracker for similar issues including closed ones
• Checked that provided video/audio/playlist URLs (if any) are alive and playable in a browser

What is the purpose of your issue?

• Feature request

---

youtube-dl -v --convert-subs srt --all-subs --embed-subs -F https://www.pornhub.com/view_video.php\?viewkey\=ph58bad3a46a5cc
[debug] System config: []
[debug] User config: []
[debug] Custom config: []
[debug] Command-line args: ['-v', '--convert-subs', 'srt', '--all-subs', '--embed-subs', '-F', 'https://www.pornhub.com/view_video.php?viewkey=ph58bad3a46a5cc']
[debug] Encodings: locale cp1253, fs mbcs, out cp737, pref cp1253
[debug] youtube-dl version 2018.07.04
[debug] Python version 3.4.4 (CPython) - Windows-7-6.1.7601-SP1
[debug] exe versions: ffmpeg N-91434-gcced03dd66, ffprobe N-91434-gcced03dd66, phantomjs 2.1.1
[debug] Proxy map: {}
[PornHub] ph58bad3a46a5cc: Downloading webpage
[PornHub] ph58bad3a46a5cc: Downloading webpage
[info] Available formats for ph58bad3a46a5cc:
format code  extension  resolution note
0            mp4        unknown

---

Description of your issue, suggested solution and other information

PornHub recently added subtitles for some videos

https://www.highsnobiety.com/p/pornhub-subtitles/

So it would be useful to be able to download them as part of the video

Examples:

https://www.pornhub.com/view_video.php?viewkey=ph5af5fef7c2aa7
https://www.pornhub.com/video?c=732