Thanks for your help, -udp-range works now!
>    -udp-range 49152-65535


I have some issues while testing Galène:

Video recordings are divided into small chucks of webm video of approx 20-60 seconds, some with different pixel aspect ratios.
In Firefox (78.13), Simulcast refuses to be activated (on) and turns to off. (auto is OK)
In the op/presenter video window the bitrate is now only numbers (without its unit of measurement)

Playing, as op/presenter, video streaming (Play local file) from a mp4  (using MacOS 10.11.6)

Chromium (95.0.4635.0): not working (black screen)
Chrome (93.0.4577.63) OK (the op/presenter gets the sound)
Firefox (78.13.0) working but with no sound for the op/presenter.
Vivaldi (4.1.2369.21): OK (op/presenter gets the sound)
Opera (78.0.4093.184): OK (op/presenter gets the sound)
Safari (11.1.2): `Play local file` option is not available.
Best.
Éric