diff --git a/DOCS/man/options.rst b/DOCS/man/options.rst
index d3380f3c22..aedd4488e9 100644
--- a/DOCS/man/options.rst
+++ b/DOCS/man/options.rst
@@ -5554,8 +5554,10 @@ them.
     no
         Disable any dithering done by mpv.
     auto
-        Automatic selection. If output bit depth cannot be detected, 8 bits per
-        component are assumed.
+        Automatic selection.
+        On ``vo=gpu``: if output bit depth cannot be detected, 8 bpc is assumed.
+        On ``vo=gpu-next``: with ``gpu-api=d3d11``, real on-the-wire bpc is used.
+        For other ``gpu-api``, 8 bpc is used for SDR content.
     8
         Dither to 8 bit output.
 
diff --git a/video/out/vo_gpu_next.c b/video/out/vo_gpu_next.c
index 3c5f558473..0faf811733 100644
--- a/video/out/vo_gpu_next.c
+++ b/video/out/vo_gpu_next.c
@@ -841,7 +841,11 @@ static void apply_target_options(struct priv *p, struct pl_frame *target)
     int dither_depth = opts->dither_depth;
     if (dither_depth == 0) {
         struct ra_swapchain *sw = p->ra_ctx->swapchain;
-        dither_depth = sw->fns->color_depth ? sw->fns->color_depth(sw) : 0;
+        if (sw->fns->color_depth) {
+            dither_depth = sw->fns->color_depth(sw);
+        } else if (!pl_color_transfer_is_hdr(target->color.transfer)) {
+            dither_depth = 8;
+        }
     }
     if (dither_depth > 0) {
         struct pl_bit_encoding *tbits = &target->repr.bits;