swscale/graph: copy scaler_params to the legacy subpass context

Fixes ticket #11448.

Signed-off-by: James Almer <jamrial@gmail.com>

libswscale/graph.c

@@ -431,6 +431,9 @@ static int add_legacy_sws_pass(SwsGraph *graph, SwsFormat src, SwsFormat dst,
     legacy_chr_pos(graph, &sws->dst_h_chr_pos, ctx->dst_h_chr_pos, &warned);
     legacy_chr_pos(graph, &sws->dst_v_chr_pos, ctx->dst_v_chr_pos, &warned);
 
+    sws->scaler_params[0] = ctx->scaler_params[0];
+    sws->scaler_params[1] = ctx->scaler_params[1];
+
     ret = sws_init_context(sws, NULL, NULL);
     if (ret < 0) {
         sws_free_context(&sws);