For filters which will create hardware frames, sets the device the
filter should create them in. All other filters will ignore this field:
in particular, a filter which consumes or processes hardware frames will
instead use the hw_frames_ctx field in AVFilterLink to carry the
hardware context information.
For filters which will create hardware frames, sets the device the filter should create them in. All other filters will ignore this field: in particular, a filter which consumes or processes hardware frames will instead use the hw_frames_ctx field in AVFilterLink to carry the hardware context information.