Edit from this morning
3/2/25 Update
Update.
Videos don't run on my old machine with Zorin Pro installed
Videos don't run on my old machine working from a Zorin Pro Try USB, so not the installed stuff
Videos DO run on my newer machine from the same Zorin Pro USB, so machine specific
Latest
I ran om@OldMesh:~$ sudo apt install vlc
[sudo] password for tom:
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following additional packages will be installed:
vlc-bin vlc-l10n vlc-plugin-access-extra vlc-plugin-notify vlc-plugin-qt
vlc-plugin-samba vlc-plugin-skins2 vlc-plugin-video-splitter
vlc-plugin-visualization
Suggested packages:
vlc-plugin-fluidsynth vlc-plugin-jack vlc-plugin-svg
The following NEW packages will be installed
vlc vlc-bin vlc-l10n vlc-plugin-access-extra vlc-plugin-notify vlc-plugin-qt
vlc-plugin-samba vlc-plugin-skins2 vlc-plugin-video-splitter
vlc-plugin-visualization
0 to upgrade, 10 to newly install, 0 to remove and 1 not to upgrade.
Need to get 8,482 kB of archives.
After this operation, 46.8 MB of additional disk space will be used.
Do you want to continue? [Y/n] y
Get:1 Index of /ubuntu jammy/universe amd64 vlc-bin amd64 3.0.16-1build7 [56.7 kB]
Get:2 Index of /ubuntu jammy/universe amd64 vlc-plugin-qt amd64 3.0.16-1build7 [1,102 kB]
Get:3 Index of /ubuntu jammy/universe amd64 vlc amd64 3.0.16-1build7 [37.3 kB]
Get:4 Index of /ubuntu jammy/universe amd64 vlc-l10n all 3.0.16-1build7 [6,636 kB]
Get:5 Index of /ubuntu jammy/universe amd64 vlc-plugin-access-extra amd64 3.0.16-1build7 [27.0 kB]
Get:6 Index of /ubuntu jammy/universe amd64 vlc-plugin-notify amd64 3.0.16-1build7 [19.4 kB]
Get:7 Index of /ubuntu jammy/universe amd64 vlc-plugin-samba amd64 3.0.16-1build7 [20.1 kB]
Get:8 Index of /ubuntu jammy/universe amd64 vlc-plugin-skins2 amd64 3.0.16-1build7 [504 kB]
Get:9 Index of /ubuntu jammy/universe amd64 vlc-plugin-video-splitter amd64 3.0.16-1build7 [35.4 kB]
Get:10 Index of /ubuntu jammy/universe amd64 vlc-plugin-visualization amd64 3.0.16-1build7 [44.0 kB]
Fetched 8,482 kB in 6s (1,376 kB/s)
Selecting previously unselected package vlc-bin.
(Reading database ... 319396 files and directories currently installed.)
Preparing to unpack .../0-vlc-bin_3.0.16-1build7_amd64.deb ...
Unpacking vlc-bin (3.0.16-1build7) ...
Selecting previously unselected package vlc-plugin-qt:amd64.
Preparing to unpack .../1-vlc-plugin-qt_3.0.16-1build7_amd64.deb ...
Unpacking vlc-plugin-qt:amd64 (3.0.16-1build7) ...
Selecting previously unselected package vlc.
Preparing to unpack .../2-vlc_3.0.16-1build7_amd64.deb ...
Unpacking vlc (3.0.16-1build7) ...
Selecting previously unselected package vlc-l10n.
Preparing to unpack .../3-vlc-l10n_3.0.16-1build7_all.deb ...
Unpacking vlc-l10n (3.0.16-1build7) ...
Selecting previously unselected package vlc-plugin-access-extra:amd64.
Preparing to unpack .../4-vlc-plugin-access-extra_3.0.16-1build7_amd64.deb ...
Unpacking vlc-plugin-access-extra:amd64 (3.0.16-1build7) ...
Selecting previously unselected package vlc-plugin-notify:amd64.
Preparing to unpack .../5-vlc-plugin-notify_3.0.16-1build7_amd64.deb ...
Unpacking vlc-plugin-notify:amd64 (3.0.16-1build7) ...
Selecting previously unselected package vlc-plugin-samba:amd64.
Preparing to unpack .../6-vlc-plugin-samba_3.0.16-1build7_amd64.deb ...
Unpacking vlc-plugin-samba:amd64 (3.0.16-1build7) ...
Selecting previously unselected package vlc-plugin-skins2:amd64.
Preparing to unpack .../7-vlc-plugin-skins2_3.0.16-1build7_amd64.deb ...
Unpacking vlc-plugin-skins2:amd64 (3.0.16-1build7) ...
Selecting previously unselected package vlc-plugin-video-splitter:amd64.
Preparing to unpack .../8-vlc-plugin-video-splitter_3.0.16-1build7_amd64.deb ...
Unpacking vlc-plugin-video-splitter:amd64 (3.0.16-1build7) ...
Selecting previously unselected package vlc-plugin-visualization:amd64.
Preparing to unpack .../9-vlc-plugin-visualization_3.0.16-1build7_amd64.deb ...
Unpacking vlc-plugin-visualization:amd64 (3.0.16-1build7) ...
Setting up vlc-plugin-video-splitter:amd64 (3.0.16-1build7) ...
Setting up vlc-bin (3.0.16-1build7) ...
Setting up vlc-l10n (3.0.16-1build7) ...
Setting up vlc-plugin-visualization:amd64 (3.0.16-1build7) ...
Setting up vlc-plugin-access-extra:amd64 (3.0.16-1build7) ...
Setting up vlc-plugin-qt:amd64 (3.0.16-1build7) ...
Setting up vlc (3.0.16-1build7) ...
Setting up vlc-plugin-notify:amd64 (3.0.16-1build7) ...
Setting up vlc-plugin-samba:amd64 (3.0.16-1build7) ...
Setting up vlc-plugin-skins2:amd64 (3.0.16-1build7) ...
Processing triggers for man-db (2.10.2-1) ...
Processing triggers for libvlc-bin:amd64 (3.0.16-1build7) ...
Processing triggers for mailcap (3.70+nmu1ubuntu1) ...
Processing triggers for desktop-file-utils (0.26-1ubuntu3) ...
Processing triggers for gnome-menus (3.36.0-1ubuntu3) ...
tom@OldMesh:~$
and now videos are working, but no sound.
And now it's all working, at least in Firefox!
EDIT. None of this helped when I had to install Zorin again - problem seems immediately after installation!