On Thu, 18 Jun 2020 at 12:17:19 +0200, Philippe Chauvat wrote: > gstreamer1.0-plugins-bad is trying to be installed but in conflict with > other packages... ... > Préparation du dépaquetage de > .../gstreamer1.0-plugins-bad_1%3a1.14.4-dmo7_amd64.deb ...
This version is from deb-multimedia.org (notice the -dmo). That's a third-party package repository which is known to contain various packages that are incompatible with what's in Debian, particularly testing/unstable. Please don't use it, and replace packages that came from dmo with the equivalents from "real Debian". In particular, dmo puts epochs on the version numbers of its packages, which cause those packages to be compared incorrectly with packages in Debian - for example this is gstreamer1.0-plugins-bad version 1.14.4, but because of the 1: epoch, dpkg will think that it is newer than the version 1.16.x in Debian testing/unstable. This is not true and can break applications. smcv