I don’t think vulnerability researchers are having trouble finding exploitable bugs in FFmpeg, so I don’t know how much this actually holds. Much of the cost center of vulnerability research is weaponization and making an exploit reliable against a specific set of targets.
(The argument also seems backwards to me: Google appears to use a lot of not-inexpensive human talent to produce high quality reports to projects, instead of dumping an ASan log and calling it a day. If all they cared about was shoveling labor onto OSS maintainers, they could make things a lot easier for themselves than they currently do!)
Internally, Google maintains their own completely separate FFMpeg fork as well as a hardened sandbox for running that fork. Since they keep pace with releases to receive security fixes, there’s potentially lots of upstreamable work (with some effort on both sides…)
My understanding from adjacent threads in this discussion is that Google does in fact make significant upstream contributions to FFmpeg. Per policy those are often made with personal emails, but multiple people have said that Google’s investment in FFmpeg’s security and codec support have been significant.
(But also, while this is great, it doesn’t make an expectation of a patch with a security report reasonable! Most security reports don’t come with patches.)
(The argument also seems backwards to me: Google appears to use a lot of not-inexpensive human talent to produce high quality reports to projects, instead of dumping an ASan log and calling it a day. If all they cared about was shoveling labor onto OSS maintainers, they could make things a lot easier for themselves than they currently do!)