merge subtitles not work?

[mr-aleks]

• I've verified and I assure that I'm running youtube-dl 2018.05.18

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?

• Bug report (encountered problems with youtube-dl)
• Site support request (request for adding support for a new site)
• Feature request (request for a new functionality)
• Question
• Other

---

Summary

I'm downloading a video with a merge of subtitles, but when I play this file it's without subtitles

---

Logs

youtube-dl.exe https://youtu.be/Xv1JzYDKoc8 --all-subs --embed-subs --verbose
[debug] System config: []
[debug] User config: []
[debug] Custom config: []
[debug] Command-line args: ['https://youtu.be/Xv1JzYDKoc8', '--all-subs', '--embed-subs', '--verbose']
[debug] Encodings: locale cp1251, fs mbcs, out cp866, pref cp1251
[debug] youtube-dl version 2018.05.18
[debug] Python version 3.4.4 (CPython) - Windows-10-10.0.17134
[debug] exe versions: ffmpeg git-2017-12-31-2906363, ffprobe git-2017-12-31-2906363
[debug] Proxy map: {}
[youtube] Xv1JzYDKoc8: Downloading webpage
[youtube] Xv1JzYDKoc8: Downloading video info webpage
[youtube] Xv1JzYDKoc8: Extracting video information
[debug] Default format spec: bestvideo+bestaudio/best
[info] Writing video subtitles to: Ролик World of Warcraft - Battle for Azeroth-Xv1JzYDKoc8.ru.vtt
WARNING: Requested formats are incompatible for merge and will be merged into mkv.
[debug] Invoking downloader on 'https://r6---sn-cxauxaxjvh-hn96.googlevideo.com/videoplayback?lmt=1512496884226762&initcwndbps=695000&beids=%5B9466591%5D&sparams=aitags%2Cclen%2Cdur%2Cei%2Cgir%2Cid%2Cinitcwndbps%2Cip%2Cipbits%2Citag%2Ckeepalive%2Clmt%2Cmime%2Cmm%2Cmn%2Cms%2Cmv%2Cpl%2Crequiressl%2Csource%2Cexpire&expire=1526617772&ipbits=0&mn=sn-cxauxaxjvh-hn96%2Csn-f5f7lne6&pl=19&mm=31%2C29&requiressl=yes&dur=269.499&id=o-AGeNwZ3dO6yHxsegK7TR_KXAW1suOhXqDyZClQLpyLY_&source=youtube&ip=93.85.46.236&mv=m&mt=1526596088&ms=au%2Crdu&c=WEB&ei=SwL-WpSEPKbY7ASl57uoBQ&fvip=2&keepalive=yes&gir=yes&clen=71964601&signature=07E97593AA756D6867ED34510E5DFA276AC9FA2E.D5B1EE279B7E8A2F449B8C9F5357EECCF963D243&itag=137&key=yt6&mime=video%2Fmp4&aitags=133%2C134%2C135%2C136%2C137%2C160%2C242%2C243%2C244%2C247%2C248%2C278&ratebypass=yes'
[download] Destination: Ролик World of Warcraft - Battle for Azeroth-Xv1JzYDKoc8.f137.mp4
[download] 100% of 68.63MiB in 00:17
[debug] Invoking downloader on 'https://r6---sn-cxauxaxjvh-hn96.googlevideo.com/videoplayback?lmt=1512496649355498&initcwndbps=695000&beids=%5B9466591%5D&sparams=clen%2Cdur%2Cei%2Cgir%2Cid%2Cinitcwndbps%2Cip%2Cipbits%2Citag%2Ckeepalive%2Clmt%2Cmime%2Cmm%2Cmn%2Cms%2Cmv%2Cpl%2Crequiressl%2Csource%2Cexpire&expire=1526617772&ipbits=0&mn=sn-cxauxaxjvh-hn96%2Csn-f5f7lne6&pl=19&mm=31%2C29&requiressl=yes&dur=269.521&id=o-AGeNwZ3dO6yHxsegK7TR_KXAW1suOhXqDyZClQLpyLY_&source=youtube&ip=93.85.46.236&mv=m&mt=1526596088&ms=au%2Crdu&c=WEB&ei=SwL-WpSEPKbY7ASl57uoBQ&fvip=2&keepalive=yes&gir=yes&clen=4131234&itag=251&signature=CA0DEF9AE9A604C94F8F813E4E066D677456DCE3.8ACC45FD7A362D57DE7F575591487394B733EEE7&key=yt6&mime=audio%2Fwebm&ratebypass=yes'
[download] Destination: Ролик World of Warcraft - Battle for Azeroth-Xv1JzYDKoc8.f251.webm
[download] 100% of 3.94MiB in 00:01
[ffmpeg] Merging formats into "Ролик World of Warcraft - Battle for Azeroth-Xv1JzYDKoc8.mkv"
[debug] ffmpeg command line: ffmpeg -y -i "file:Ролик World of Warcraft - Battle for Azeroth-Xv1JzYDKoc8.f137.mp4" -i "file:Ролик World of Warcraft - Battle for Azeroth-Xv1JzYDKoc8.f251.webm" -c copy -map "0:v:0" -map "1:a:0" "file:Ролик World of Warcraft - Battle for Azeroth-Xv1JzYDKoc8.temp.mkv"
Deleting original file Ролик World of Warcraft - Battle for Azeroth-Xv1JzYDKoc8.f137.mp4 (pass -k to keep)
Deleting original file Ролик World of Warcraft - Battle for Azeroth-Xv1JzYDKoc8.f251.webm (pass -k to keep)
[ffmpeg] Embedding subtitles in 'Ролик World of Warcraft - Battle for Azeroth-Xv1JzYDKoc8.mkv'
[debug] ffmpeg command line: ffmpeg -y -i "file:Ролик World of Warcraft - Battle for Azeroth-Xv1JzYDKoc8.mkv" -i "file:Ролик World of Warcraft - Battle for Azeroth-Xv1JzYDKoc8.ru.vtt" -map 0 -c copy -map "-0:s" -map "1:0" "-metadata:s:s:0" "language=rus" "file:Ролик World of Warcraft - Battle for Azeroth-Xv1JzYDKoc8.temp.mkv"
Deleting original file Ролик World of Warcraft - Battle for Azeroth-Xv1JzYDKoc8.ru.vtt (pass -k to keep)

[remitamine]

the embedded subtitle is playable with both mpv and vlc.

[ffmpeg] Merging formats into "Ролик World of Warcraft - Battle for Azeroth-Xv1JzYDKoc8.mkv"
[debug] ffmpeg command line: ffmpeg -y -i 'file:Ролик World of Warcraft - Battle for Azeroth-Xv1JzYDKoc8.f137.mp4' -i 'file:Ролик World of Warcraft - Battle for Azeroth-Xv1JzYDKoc8.f251.webm' -c copy -map 0:v:0 -map 1:a:0 'file:Ролик World of Warcraft - Battle for Azeroth-Xv1JzYDKoc8.temp.mkv'
Deleting original file Ролик World of Warcraft - Battle for Azeroth-Xv1JzYDKoc8.f137.mp4 (pass -k to keep)
Deleting original file Ролик World of Warcraft - Battle for Azeroth-Xv1JzYDKoc8.f251.webm (pass -k to keep)
[ffmpeg] Embedding subtitles in 'Ролик World of Warcraft - Battle for Azeroth-Xv1JzYDKoc8.mkv'
[debug] ffmpeg command line: ffmpeg -y -i 'file:Ролик World of Warcraft - Battle for Azeroth-Xv1JzYDKoc8.mkv' -i 'file:Ролик World of Warcraft - Battle for Azeroth-Xv1JzYDKoc8.ru.vtt' -map 0 -c copy -map -0:s -map 1:0 -metadata:s:s:0 language=rus 'file:Ролик World of Warcraft - Battle for Azeroth-Xv1JzYDKoc8.temp.mkv'
Deleting original file Ролик World of Warcraft - Battle for Azeroth-Xv1JzYDKoc8.ru.vtt (pass -k to keep)

ffprobe Ролик\ World\ of\ Warcraft\ -\ Battle\ for\ Azeroth-Xv1JzYDKoc8.mkv 
ffprobe version 4.0 Copyright (c) 2007-2018 the FFmpeg developers
  built with gcc 8.1.0 (GCC)
  configuration: --prefix=/usr --disable-debug --disable-static --disable-stripping --enable-avresample --enable-fontconfig --enable-gmp --enable-gnutls --enable-gpl --enable-ladspa --enable-libass --enable-libbluray --enable-libdrm --enable-libfreetype --enable-libfribidi --enable-libgsm --enable-libiec61883 --enable-libmodplug --enable-libmp3lame --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libv4l2 --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxcb --enable-libxml2 --enable-libxvid --enable-nvenc --enable-omx --enable-shared --enable-version3
  libavutil      56. 14.100 / 56. 14.100
  libavcodec     58. 18.100 / 58. 18.100
  libavformat    58. 12.100 / 58. 12.100
  libavdevice    58.  3.100 / 58.  3.100
  libavfilter     7. 16.100 /  7. 16.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  1.100 /  5.  1.100
  libswresample   3.  1.100 /  3.  1.100
  libpostproc    55.  1.100 / 55.  1.100
Input #0, matroska,webm, from 'Ролик World of Warcraft - Battle for Azeroth-Xv1JzYDKoc8.mkv':
  Metadata:
    MINOR_VERSION   : 0
    COMPATIBLE_BRANDS: iso6avc1mp41
    MAJOR_BRAND     : dash
    ENCODER         : Lavf58.12.100
  Duration: 00:04:29.52, start: -0.007000, bitrate: 2257 kb/s
    Stream #0:0: Video: h264 (High), yuv420p(tv, bt709, progressive), 1920x1080 [SAR 1:1 DAR 16:9], 24 fps, 24 tbr, 1k tbn, 48 tbc (default)
    Metadata:
      HANDLER_NAME    : VideoHandler
      DURATION        : 00:04:29.506000000
    Stream #0:1(eng): Audio: opus, 48000 Hz, stereo, fltp (default)
    Metadata:
      DURATION        : 00:04:29.521000000
    Stream #0:2(rus): Subtitle: webvtt
    Metadata:
      DURATION        : 00:03:58.002000000

mpv Ролик\ World\ of\ Warcraft\ -\ Battle\ for\ Azeroth-Xv1JzYDKoc8.mkv 
Playing: Ролик World of Warcraft - Battle for Azeroth-Xv1JzYDKoc8.mkv
 (+) Video --vid=1 (*) (h264 1920x1080 24.000fps)
 (+) Audio --aid=1 --alang=eng (*) (opus 2ch 48000Hz)
     Subs  --sid=1 --slang=rus (webvtt-webm)
AO: [pulse] 48000Hz stereo 2ch float
VO: [gpu] 1920x1080 yuv420p
AV: 00:00:01 / 00:04:29 (0%) A-V:  0.000
Track switched:
 (+) Video --vid=1 (*) (h264 1920x1080 24.000fps)
 (+) Audio --aid=1 --alang=eng (*) (opus 2ch 48000Hz)
 (+) Subs  --sid=1 --slang=rus (webvtt-webm)