CentOS

Dear all,

I have just installed CentOS Stream 9, the OS works perfectly but I can not find the RPMs that I normally used in the previous CentOS releases.
For example I can not find OpenCV, Okular and Gimp and I have not succeeded with the installation of ffmpeg and VLC.
I enabled the AppStream, BaseOS, CRB, epel, epel-next and the rpmfusion-free and nonfree (for EL8) repos.

Please, can someone help me?

CentOS Stream 9 is an alpha distro (it's a beta of the RHEL 9 beta) and I suspect that Red Hat have removed/deprecated various packages as they normally do at a major version release. In addition, some at least of the packages you mention are from EPEL or other third party yum repos like rpmfusion who do not (yet) support 9 and may not do so until it goes GA sometime next year (presumably). I believe theree is an EPEL-next repo that may be for 9 though it might be for 8-Stream.

For packages that are or were in BaseOS/AppStream and to a lesser extent Powertools/CRB in CentOS/RHEL8 you may want to try raising bugs as per https://wiki.centos.org/ReportBugs and see what RH say, if they say anything!

Edit: in 8, gimp was in appstream, opencv was in powertools (CRB) and everything else you mention was in EPEL or rpmfusion.