The current deband filter does not actually do a very good job
debanding, because it doesn't advance the internal PRNG in any way. This
is mostly my fault for not exposing pl_dispatch_reset_frame, which is
what e.g. pl_renderer uses internally to advance the PRNG state. On
newer libplacebo (v4.167+), that's the function we should be calling to
fix this.
As a work-around, that also works for older libplacebo, we can simply
pl_shader_reset the shaders we get from pl_dispatch_begin to include
a frame index of our choosing, without breaking anything.
The current deband filter does not actually do a very good job debanding, because it doesn't advance the internal PRNG in any way. This is mostly my fault for not exposing
pl_dispatch_reset_frame, which is what e.g. pl_renderer uses internally to advance the PRNG state. On newer libplacebo (v4.167+), that's the function we should be calling to fix this.As a work-around, that also works for older libplacebo, we can simply
pl_shader_resetthe shaders we get frompl_dispatch_beginto include a frame index of our choosing, without breaking anything.