diff --git a/src/model/vae/wan_vae.hpp b/src/model/vae/wan_vae.hpp
index 035deae3..8d14cf95 100644
--- a/src/model/vae/wan_vae.hpp
+++ b/src/model/vae/wan_vae.hpp
@@ -82,6 +82,20 @@ namespace WAN {
             }
 
             x = ggml_ext_pad_ext(ctx->ggml_ctx, ctx->backend, x, lp0, rp0, lp1, rp1, lp2, rp2, 0, 0, ctx->circular_x_enabled, ctx->circular_y_enabled);
+            if (w->ne[2] == 1 && x->ne[2] == 1 && x->ne[3] == in_channels) {
+                // One frame through a one-frame-deep kernel is a 2D conv; backends without
+                // im2col_3d (Metal) otherwise fall back to a much slower direct conv_3d.
+                if (!ggml_is_contiguous(x)) {
+                    x = ggml_cont(ctx->ggml_ctx, x);
+                }
+                ggml_tensor* x2 = ggml_reshape_4d(ctx->ggml_ctx, x, x->ne[0], x->ne[1], in_channels, 1);
+                ggml_tensor* w2 = ggml_reshape_4d(ctx->ggml_ctx, w, w->ne[0], w->ne[1], in_channels, out_channels);
+                x2              = ggml_ext_conv_2d(ctx->ggml_ctx, x2, w2, b,
+                                                   std::get<2>(stride), std::get<1>(stride), 0, 0,
+                                                   std::get<2>(dilation), std::get<1>(dilation),
+                                                   ctx->conv2d_direct_enabled);
+                return ggml_reshape_4d(ctx->ggml_ctx, x2, x2->ne[0], x2->ne[1], 1, out_channels);
+            }
             return ggml_ext_conv_3d(ctx->ggml_ctx, ctx->backend, x, w, b, in_channels,
                                     std::get<2>(stride), std::get<1>(stride), std::get<0>(stride),
                                     0, 0, 0,