Details of the rights clearance for synchronisation rights for UGC platforms are governed by the rights management conditions which you can access under management of synchronisation rights.
In order to enable rightsholders to make a decision on the revocation of rights, GEMA will notify them in advance if it is about to conclude a licence agreement for a UGC platform. This information will be communicated via the GEMA website. The deadline for submitting the rights revocation declaration with respect to individual services or providers shall be 4 weeks from the publication of the information by GEMA that it intends to license the synchronisation rights for this service/provider. In principle, a blanket [rights] revocation for all services can be declared at any time. It shall comprise all services with regards to which GEMA has not made an announcement at least 4 weeks before the declaration of the rights revocation that it intends to license the synchronisation rights for commercial UGC. The rights revocation can also be declared by publishers on behalf of the authors they represent. Publishers that have been authorised by several authors to issue the rights revocation, can declare the revocation jointly for the works of all the authors they represent or limit the declaration on the works of individual authors. A rights revocation for individual works or uses/exploitations is, however, not possible.