Wouldn't they just fork it, fix their own bugs and stop contributing at all?
replies(6):
Their choice becomes to: - maintain a complex fork, constantly integrating from upstream. - Or pin to some old version and maybe go through a Herculean effort to rebase when something they truly must have merges upstream. - Or genuinely fork it and employ an expert in this highly specific domain to write what will often end up being parallel features and security patches to mainline FFmpeg.
Or, of course, pay someone in doing OSS to fix it in mainline. Which is the beauty of open source; that’s genuinely the least painful option, and also happens to be the one that benefits the community the most.