Tiktok issue

[TaktakTaktouk]

Checklist

• I'm reporting a broken site support
• I've verified that I'm running youtube-dl version 2020.03.24
• I've checked that all provided URLs are alive and playable in a browser
• I've checked that all URLs and arguments with special characters are properly quoted or escaped
• I've searched the bugtracker for similar issues including closed ones

Verbose log

 youtube-dl "https://www.tiktok.com/@vloggerbubu/video/6811471750153522437" -v
[debug] System config: []
[debug] User config: []
[debug] Custom config: []
[debug] Command-line args: [u'https://www.tiktok.com/@vloggerbubu/video/6811471750153522437', u'-v']
[debug] Encodings: locale UTF-8, fs utf-8, out UTF-8, pref UTF-8
[debug] youtube-dl version 2020.03.24
[debug] Python version 2.7.10 (CPython) - Darwin-17.7.0-x86_64-i386-64bit
[debug] exe versions: ffmpeg 4.2.2, ffprobe 4.2.2, rtmpdump 2.4
[debug] Proxy map: {}
[generic] 6811471750153522437: Requesting header
WARNING: Falling back on generic information extractor.
[generic] 6811471750153522437: Downloading webpage
[generic] 6811471750153522437: Extracting information
[download] Downloading playlist: Vlogger Bubu on TikTok
[generic] playlist Vlogger Bubu on TikTok: Collected 1 video ids (downloading 1 of them)
[download] Downloading video 1 of 1
[debug] Default format spec: bestvideo+bestaudio/best
[debug] Invoking downloader on u'https://v16.muscdn.com/f70d40d6730c549eea25aea955d616e2/5e8a1634/video/tos/useast2a/tos-useast2a-ve-0068c003/fb2327fa2e8745aa9c4336dc983ef06f/?a=1233&br=1530&bt=765&cr=0&cs=0&dr=0&ds=3&er=&l=2020040511322801011522807812B5F660&lr=tiktok_m&qs=0&rc=M3Zobm93ZWxtdDMzNzczM0ApNmlnOTk8Z2RlN2Y2OjVnOWdtXmZqXzZpNTBfLS0vMTZzcy1iLTQ2MF4yMzAyXy0wNjU6Yw==&vl=&vr='
[download] Destination: Vlogger Bubu on TikTok-6811471750153522437.unknown_video
[download] 100% of 799.60KiB in 00:01
[download] Finished downloading playlist: Vlogger Bubu on TikTok

Description

the extension of the downloaded file is ".unknown_video" so I have to rename it to .mp4 to make the video playable on my video player.