[FFmpeg-devel] [PATCH v5 4/5] lavfi/format: wrap auto filters into structures

[Wu, Tong1]

>Possibility for infinite loops?

>In what cases this helps, have graphs examples to test?

Now we only have scale filter that can be auto inserted. This patch set basically gives the potential capability to add more auto filters. An auto hwmap filter is introduced for now. It can be beneficial to hwmap use cases.

For example,
ffmpeg -init_hw_device d3d11va=d3d11 -init_hw_device qsv=qsv at d3d11 -hwaccel d3d11va -hwaccel_output_format d3d11 -i input.mp4 -vf “hwmap=derive_device=qsv:extra_hw_frames=16,format=qsv” -c:v h264_qsv output.mp4

Now we don’t have to explicitly specify hwmap. The auto filter mechanism will try to insert a hwmap filter automatically. The command line will be much simpler.

ffmpeg -init_hw_device d3d11va=d3d11 -init_hw_device qsv=qsv at d3d11 -hwaccel d3d11va -hwaccel_output_format d3d11 -i input.mp4 -c:v h264_qsv output.mp4

Could you explain a little bit why the loop could be infinite?