MP4 (x264 enc) files aren't played in Firefox built-in players or read in mobile apps (except VLC)

[belsholff]

Expected Behavior

After record my screen using MP4 format and try to play it, I can do this using Firefox (desktop and mobile), and Android opensource built-in player or Whatsapp (when sending and editing video).

Current Behavior

My screencasts can't be played in FF, Android apps as built-in player, or Whatsapp. Slack does the upload but its reproduction depends on browser/mobile player. Instead, using Google Chrome (desktop tested), VLC (desktop or mobile), or ffplay, everything works.

When the file is converted using ffmpeg to another format, with another codec, it's still not reproducible in first listed players. In last listed players, like source file, it is.

In opposite, when I use built-in screencast embedded in GNOME, or use ESC in a format that not handle x264 codec, it works, including when I record in these formats and use ffmpeg to convert to MP4 using the libx264 codec (maybe an attention point).

Logs

journalctl /usr/bin/gnome-shell --since=15:27 --no-pager --output=cat
[ESC]-*-refresh indicator -A false -F true
[ESC]-*-right click indicator
[ESC]-*-start recording
[ESC]-*-recording full area
[ESC]-*-instant recording called
[ESC]-&-start video recording
[ESC]-§-get file extension C-> 2
[ESC]-§-COMPOSE GSP
[ESC]-#-mixer _init
[ESC]-#-mixer exist -> [object instance wrapper GIName:Gvc.MixerControl jsobj@0x2a9a8c080f40 native@0x557b816ec360] state -> 1
[ESC]-§-get option||devW: 0||devA: 0||Qgsp: 1||Qwc: ||Res: -1||Cont: 2
[ESC]-§-SCREEN
[ESC]-§-resolution option: -1
[ESC]-§-compose resolution: 
[ESC]-§-final GSP : x264enc psy-tune="animation" speed-preset="fast" subme=5 qp-min=18 qp-max=28 threads=%T ! queue max-size-buffers=0 max-size-time=0 max-size-bytes=0 ! mp4mux
[ESC]-&-path/file template : /home/felipe/Vídeos/Screencast_%d_%t.mp4
[ESC]-*-refresh indicator -A false -F undefined
Recording to /home/felipe/Vídeos/Screencast_06-08-2020_15:27:26.mp4
[ESC]-&-screencast execute - true - /home/felipe/Vídeos/Screencast_06-08-2020_15:27:26.mp4
[ESC]-*-record OK
[ESC]-*-replace STD indicator
[ESC]-*-update abs file path -> /home/felipe/Vídeos/Screencast_06-08-2020_15:27:26.mp4
[ESC]-*-refresh indicator -A true -F undefined
[ESC]-*-refresh indicator -A true -F false
[ESC]-*-refresh indicator -A true -F false
[ESC]-*-refresh indicator -A true -F true
[ESC]-*-refresh indicator -A true -F false
[ESC]-*-refresh indicator -A true -F true
[ESC]-*-right click indicator
[ESC]-*-stop recording
[ESC]-&-stop video recording
[ESC]-*-refresh indicator -A false -F undefined
[ESC]-&-screencast stop - true
[ESC]-*-refresh indicator -A false -F false
[ESC]-*-refresh indicator -A false -F false

Your Environment

• Where did you download the extension?
  [x] Gnome shell extension website
  [ ] From Git (Add commit tag)

• Gnome shell version: 3.36.3 from apt

• Operating System and version: Ubuntu 20.04 (x64)

• Display server: X11

castReferredByLog.zip