avcodec/dovi_rpu: guard ext blocks by dm_metadata_present

In the spec, dm_metadata_present also toggles all extension blocks, so
we need to move them inside the branch.

libavcodec/dovi_rpudec.c

@@ -625,9 +625,6 @@ int ff_dovi_rpu_parse(DOVIContext *s, const uint8_t *rpu, size_t rpu_size,
         color->source_min_pq = get_bits(gb, 12);
         color->source_max_pq = get_bits(gb, 12);
         color->source_diagonal = get_bits(gb, 10);
-    } else {
-        s->color = &ff_dovi_color_default;
-    }
 
         /* Parse extension blocks */
         s->num_ext_blocks = 0;
@@ -642,6 +639,10 @@ int ff_dovi_rpu_parse(DOVIContext *s, const uint8_t *rpu, size_t rpu_size,
                 return ret;
             }
         }
+    } else {
+        s->color = &ff_dovi_color_default;
+        s->num_ext_blocks = 0;
+    }
 
     return 0;
 

libavcodec/dovi_rpuenc.c

@@ -508,6 +508,8 @@ int ff_dovi_rpu_generate(DOVIContext *s, const AVDOVIMetadata *metadata,
 
     vdr_dm_metadata_present = memcmp(color, &ff_dovi_color_default, sizeof(*color));
     use_prev_vdr_rpu = !memcmp(s->vdr[vdr_rpu_id], mapping, sizeof(*mapping));
+    if (num_ext_blocks_v1 || num_ext_blocks_v2)
+        vdr_dm_metadata_present = 1;
 
     if (vdr_dm_metadata_present && !s->dm) {
         s->dm = ff_refstruct_allocz(sizeof(AVDOVIColorMetadata));
@@ -657,10 +659,8 @@ int ff_dovi_rpu_generate(DOVIContext *s, const AVDOVIMetadata *metadata,
 
         memcpy(s->dm, color, sizeof(*color));
         s->color = s->dm;
-    } else {
-        s->color = &ff_dovi_color_default;
-    }
 
+        /* Extension blocks */
         set_ue_golomb(pb, num_ext_blocks_v1);
         align_put_bits(pb);
         for (int i = 0; i < metadata->num_ext_blocks; i++)
@@ -672,6 +672,10 @@ int ff_dovi_rpu_generate(DOVIContext *s, const AVDOVIMetadata *metadata,
             for (int i = 0; i < metadata->num_ext_blocks; i++)
                 generate_ext_v2(pb, av_dovi_get_ext(metadata, i));
         }
+    } else {
+        s->color = &ff_dovi_color_default;
+        s->num_ext_blocks = 0;
+    }
 
     flush_put_bits(pb);
     crc = av_bswap32(av_crc(av_crc_get_table(AV_CRC_32_IEEE), -1,