That sounds nice in theory, but it seems obvious to me there is a major discrepancy between who is burdened with this responsibility, and who benefits from the result. Given many of these contributors are unpaid volunteers, maybe the infrastructure provider needs to secure FFmpeg in another way, for example by restricting codecs or by running it in a container?

The creator of borg and k8s of course already run such tools for untrusted inputs in containers, but there is also an endless stream of container escapes.