Ideally, users should be using lavfi-complex instead of lavfi-bridge
for such a use case, however currently lavfi-complex doesn't support
hwdec. So we can allow filters with dynamic inputs to work with
lavfi-bridge, at the cost of them only being able to take in
only one input. This should probably be reverted when/if lavfi-complex
has hwdec, but for now this allows us to use libplacebo
as a video filter with hwdec in mpv again.
llyyr
8bf3fe7e2a