vo_gpu_next: add --hdr-reference-white

Author: kasper93

DOCS/interface-changes/sdr-reference-white.txt

@@ -0,0 +1 @@
+add `--hdr-reference-white`

DOCS/man/options.rst

@@ -7342,6 +7342,18 @@ them.
     encoding into the target colorspace, so after the application of
     ``--target-trc``. (Only for ``--vo=gpu-next``)
 
+``--hdr-reference-white=<auto|10-1000000>``
+    Specifies the assumed peak brightness of the mastering display for SDR
+    content, in cd/m² (nits). This is used as HDR diffuse white level for SDR
+    content. Essentially this is the SDR brightness in HDR container.
+    Default is 203 cd/m². (Only for ``--vo=gpu-next``)
+
+    .. note::
+
+        This option overrides the ``--target-peak`` if is set and the target
+        transfer function is SDR. This way you can control SDR output separately
+        from HDR output.
+
 ``--tone-mapping=<value>``
     Specifies the algorithm used for tone-mapping images onto the target
     display. This is relevant for both HDR->SDR conversion as well as gamut

video/out/gpu/video.c

@@ -443,6 +443,8 @@ const struct m_sub_options gl_video_conf = {
         {"target-trc", OPT_CHOICE_C(target_trc, pl_csp_trc_names)},
         {"target-peak", OPT_CHOICE(target_peak, {"auto", 0}),
             M_RANGE(10, 10000)},
+        {"hdr-reference-white", OPT_CHOICE(hdr_reference_white, {"auto", 0}),
+            M_RANGE(10, 10000)},
         {"target-contrast", OPT_CHOICE(target_contrast, {"auto", 0}, {"inf", -1}),
             M_RANGE(10, 1000000)},
         {"target-gamut", OPT_CHOICE_C(target_gamut, pl_csp_prim_names)},

video/out/gpu/video.h

@@ -138,6 +138,7 @@ struct gl_video_opts {
     int target_prim;
     int target_trc;
     int target_peak;
+    int hdr_reference_white;
     int target_contrast;
     int target_gamut;
     struct gl_tone_map_opts tone_map;

video/out/vo_gpu_next.c

@@ -671,6 +671,10 @@ static bool map_frame(pl_gpu gpu, pl_tex *tex, const struct pl_source_frame *src
         .user_data = mpi,
     };
 
+    const struct gl_video_opts *opts = p->opts_cache->opts;
+    if (opts->hdr_reference_white && !pl_color_transfer_is_hdr(frame->color.transfer))
+        frame->color.hdr.max_luma = opts->hdr_reference_white;
+
     if (fp->hwdec) {
 
         struct mp_imgfmt_desc desc = mp_imgfmt_get_desc(par.imgfmt);
@@ -871,6 +875,10 @@ static void apply_target_options(struct priv *p, struct pl_frame *target,
         target->color.transfer = opts->target_trc;
     if (opts->target_peak && (!target->color.hdr.max_luma || !hint))
         target->color.hdr.max_luma = opts->target_peak;
+    if (opts->hdr_reference_white && (!target->color.hdr.max_luma || !hint) &&
+        !pl_color_transfer_is_hdr(target->color.transfer)) {
+        target->color.hdr.max_luma = opts->hdr_reference_white;
+    }
     if ((!target->color.hdr.min_luma || !hint))
         apply_target_contrast(p, &target->color, min_luma);
     if (opts->target_gamut) {
@@ -1172,6 +1180,8 @@ static bool draw_frame(struct vo *vo, struct vo_frame *frame)
             hint.transfer = opts->target_trc;
         if (opts->target_peak)
             hint.hdr.max_luma = opts->target_peak;
+        if (opts->hdr_reference_white && !pl_color_transfer_is_hdr(hint.transfer))
+            hint.hdr.max_luma = opts->hdr_reference_white;
         // Always set maxCLL, display uses this metadata and we shouldn't let it
         // fallback to default value.
         if (!hint.hdr.max_cll)