lavfi/asetnsamples: switch to AVFrame
lavfi/amerge: switch to AVFrame
lavfi/atempo: switch to AVFrame
lavfi/vf_decimate: switch to AVFrame
lavfi/sendcmd: switch to AVFrame.
lavfi/biquads: switch to AVFrame
lavfi/earwax: switch to AVFrame.
lavfi/aevalsrc: switch to AVFrame.