avcodec/cbs_h265: set default VUI parameters when vui_parameters_present_flag is false

Based on cbs_h264 code.

Should fix ticket #8752.
Signed-off-by: James Almer <jamrial@gmail.com>
(cherry picked from commit d1c55fc46019229b5526768ffdb0e1e67beb21ff)

libavcodec/cbs_h265_syntax_template.c

@@ -744,6 +744,32 @@ static int FUNC(sps_scc_extension)(CodedBitstreamContext *ctx, RWContext *rw,
     return 0;
 }
 
+static int FUNC(vui_parameters_default)(CodedBitstreamContext *ctx,
+                                        RWContext *rw, H265RawVUI *current,
+                                        H265RawSPS *sps)
+{
+    infer(aspect_ratio_idc, 0);
+
+    infer(video_format,             5);
+    infer(video_full_range_flag,    0);
+    infer(colour_primaries,         2);
+    infer(transfer_characteristics, 2);
+    infer(matrix_coefficients,      2);
+
+    infer(chroma_sample_loc_type_top_field,    0);
+    infer(chroma_sample_loc_type_bottom_field, 0);
+
+    infer(tiles_fixed_structure_flag,    0);
+    infer(motion_vectors_over_pic_boundaries_flag, 1);
+    infer(min_spatial_segmentation_idc,  0);
+    infer(max_bytes_per_pic_denom,       2);
+    infer(max_bits_per_min_cu_denom,     1);
+    infer(log2_max_mv_length_horizontal, 15);
+    infer(log2_max_mv_length_vertical,   15);
+
+    return 0;
+}
+
 static int FUNC(sps)(CodedBitstreamContext *ctx, RWContext *rw,
                      H265RawSPS *current)
 {
@@ -908,6 +934,8 @@ static int FUNC(sps)(CodedBitstreamContext *ctx, RWContext *rw,
     flag(vui_parameters_present_flag);
     if (current->vui_parameters_present_flag)
         CHECK(FUNC(vui_parameters)(ctx, rw, &current->vui, current));
+    else
+        CHECK(FUNC(vui_parameters_default)(ctx, rw, &current->vui, current));
 
     flag(sps_extension_present_flag);
     if (current->sps_extension_present_flag) {