vo_gpu_next: change --target-colorspace-hint to auto by default

Auto mode will also enable hint for SDR formats if target metadata is
reported by current output context.

DOCS/interface-changes/target-colorspace-hint.txt

@@ -0,0 +1 @@
+Change `--target-colorspace-hint` to `auto` by default. Auto mode will also enable hint for SDR formats if target metadata is reported by current output context.

DOCS/man/options.rst

@@ -7017,11 +7017,20 @@ them.
         image's native colorspace and output normalized non-linear RGB.
 
 ``--target-colorspace-hint=<auto|yes|no>``
-    Automatically configure the output colorspace of the display to pass
+    When enabled, output colorspace metadata will be set on the swapchain
-    through the input values of the stream (e.g. for HDR passthrough), if
+    depending on the GPU context and platform this may affect compositor/display.
-    possible. In ``auto`` mode, the target colorspace is only set,
+    This can be used for "HDR passthrough" and to set the output colorspace
-    if the display signals support for HDR colorspace.
+    for SDR content. In ``auto`` mode, the target colorspace is only set if the
-    Requires a supporting driver and ``--vo=gpu-next``. (Default: ``no``)
+    current display parameters are known. Currently, this is supported on
+    Wayland, D3D11 and winvk contexts. The ``yes`` option will always try to set
+    the colorspace, you may need to adjust the ``--target-*`` options to match
+    your display capabilities.
+    Requires a supporting driver and ``--vo=gpu-next``. (Default: ``auto``)
+
+    .. note::
+        Auto detected target colorspace metadata is not guaranteed to be always
+        best choice. It depends on your compositor, driver, and display
+        capabilities. However in most cases ``auto`` mode should work fine.
 
 ``--target-colorspace-hint-mode=<target|source>``
     Select which metadata to use for the ``--target-colorspace-hint``.

video/out/vo_gpu_next.c

@@ -216,6 +216,7 @@ const struct m_sub_options gl_next_conf = {
         .inter_preserve = true,
         .sub_hdr_peak = PL_COLOR_SDR_WHITE,
         .image_subs_hdr_peak = PL_COLOR_SDR_WHITE,
+        .target_hint = -1,
     },
     .size = sizeof(struct gl_next_opts),
     .change_flags = UPDATE_VIDEO,
@@ -1009,11 +1010,6 @@ static bool draw_frame(struct vo *vo, struct vo_frame *frame)
     // TODO: Implement this for all backends
     if (sw->fns->target_csp)
         target_csp = sw->fns->target_csp(sw);
-    // Assume HDR is supported, if query is not available
-    if (target_csp.transfer == PL_COLOR_TRC_UNKNOWN) {
-      target_csp = (struct pl_color_space){
-          .transfer = opts->target_trc ? opts->target_trc : PL_COLOR_TRC_PQ };
-    }
     if (!pl_color_transfer_is_hdr(target_csp.transfer)) {
         // Don't use reported display peak in SDR mode. Mostly because libplacebo
         // forcefully switches to PQ if hinting hdr metadata, ignoring the transfer
@@ -1028,7 +1024,12 @@ static bool draw_frame(struct vo *vo, struct vo_frame *frame)
     struct pl_color_space hint;
     bool target_hint = p->next_opts->target_hint == 1 ||
                        (p->next_opts->target_hint == -1 &&
-                        pl_color_transfer_is_hdr(target_csp.transfer));
+                        target_csp.transfer != PL_COLOR_TRC_UNKNOWN);
+    // Assume HDR is supported, if target_csp() is not available
+    if (target_csp.transfer == PL_COLOR_TRC_UNKNOWN) {
+        target_csp = (struct pl_color_space){
+            .transfer = opts->target_trc ? opts->target_trc : PL_COLOR_TRC_PQ };
+    }
     if (target_hint && frame->current) {
         const struct pl_color_space *source = &frame->current->params.color;
         const struct pl_color_space *target = &target_csp;