As much as I hate to be on Google's side I think they're doing a reasonable thing here. Valid bug reports are valuable contributions on their own, and disclosing security issues is standard practice. Not disclosing them doesn't help anyone. Security through obscurity is not security. If neither FFMPEG nor Google dedicate resources to fixing the issue in 90 days, making it public at least ensures that it gets visibility and thus has a higher chance to get fixed by a third party.
I'm sure Google could (and probably should) do even more to help, but FFMPEG directing social media rage at a company for contributing to their project is a bone-headed move. There are countless non-Google companies relying on FFMPEG that do much less for the project, and a shit show like this is certainly not going to encourage them to get involved.
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