[FFmpeg-devel] [PATCH 2/8] avcodec/dovi_rpu: properly handle vdr_dm_metadata_present

[Niklas Haas <ffmpeg@haasn.xyz>]

From: Niklas Haas <git@haasn.dev>

When this is 0, the metadata is explicitly inferred to stated default
values from the spec, rather than inferred from the previous frame's
values.

Likewise, when encoding, instead of checking if the value changed since
the last frame, we need to check if it differs from the default.
---
 libavcodec/dovi_rpu.c    | 43 ++++++++++++++++++++++++++++++++++++++++
 libavcodec/dovi_rpu.h    |  3 +++
 libavcodec/dovi_rpudec.c |  2 ++
 libavcodec/dovi_rpuenc.c | 10 +++++-----
 4 files changed, 53 insertions(+), 5 deletions(-)

diff --git a/libavcodec/dovi_rpu.c b/libavcodec/dovi_rpu.c
index b26c19dd5e..91134e031d 100644
--- a/libavcodec/dovi_rpu.c
+++ b/libavcodec/dovi_rpu.c
@@ -86,3 +86,46 @@ int ff_dovi_guess_profile_hevc(const AVDOVIRpuDataHeader *hdr)
 
     return 0; /* unknown */
 }
+
+const AVDOVIColorMetadata ff_dovi_color_default = {
+    .dm_metadata_id     = 0,
+    .scene_refresh_flag = 0,
+    .ycc_to_rgb_matrix = {
+        {  9575, 8192 },
+        {     0, 8192 },
+        { 14742, 8192 },
+        {  9575, 8192 },
+        {  1754, 8192 },
+        {  4383, 8192 },
+        {  9575, 8192 },
+        { 17372, 8192 },
+        {     0, 8192 },
+    },
+    .ycc_to_rgb_offset = {
+        { 1, 4 },
+        { 2, 1 },
+        { 2, 1 },
+    },
+    .rgb_to_lms_matrix = {
+        {  5845, 16384 },
+        {  9702, 16384 },
+        {   837, 16384 },
+        {  2568, 16384 },
+        { 12256, 16384 },
+        {  1561, 16384 },
+        {     0, 16384 },
+        {   679, 16384 },
+        { 15705, 16384 },
+    },
+    .signal_eotf            = 39322,
+    .signal_eotf_param0     = 15867,
+    .signal_eotf_param1     = 228,
+    .signal_eotf_param2     = 1383604,
+    .signal_bit_depth       = 14,
+    .signal_color_space     = 0,
+    .signal_chroma_format   = 0,
+    .signal_full_range_flag = 1,
+    .source_min_pq          = 62,
+    .source_max_pq          = 3696,
+    .source_diagonal        = 42,
+};
diff --git a/libavcodec/dovi_rpu.h b/libavcodec/dovi_rpu.h
index 8ce0c88e9d..c784afbe4b 100644
--- a/libavcodec/dovi_rpu.h
+++ b/libavcodec/dovi_rpu.h
@@ -157,4 +157,7 @@ int ff_dovi_rpu_generate(DOVIContext *s, const AVDOVIMetadata *metadata,
  */
 int ff_dovi_guess_profile_hevc(const AVDOVIRpuDataHeader *hdr);
 
+/* Default values for AVDOVIColorMetadata */
+extern const AVDOVIColorMetadata ff_dovi_color_default;
+
 #endif /* AVCODEC_DOVI_RPU_H */
diff --git a/libavcodec/dovi_rpudec.c b/libavcodec/dovi_rpudec.c
index d1dcc3a262..cf2152988c 100644
--- a/libavcodec/dovi_rpudec.c
+++ b/libavcodec/dovi_rpudec.c
@@ -616,6 +616,8 @@ 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 */
diff --git a/libavcodec/dovi_rpuenc.c b/libavcodec/dovi_rpuenc.c
index 3c3e0f84c0..242cd76c58 100644
--- a/libavcodec/dovi_rpuenc.c
+++ b/libavcodec/dovi_rpuenc.c
@@ -441,7 +441,7 @@ int ff_dovi_rpu_generate(DOVIContext *s, const AVDOVIMetadata *metadata,
     const AVDOVIRpuDataHeader *hdr;
     const AVDOVIDataMapping *mapping;
     const AVDOVIColorMetadata *color;
-    int vdr_dm_metadata_changed, vdr_rpu_id, use_prev_vdr_rpu, profile,
+    int vdr_dm_metadata_present, vdr_rpu_id, use_prev_vdr_rpu, profile,
         buffer_size, rpu_size, pad, zero_run;
     int num_ext_blocks_v1, num_ext_blocks_v2;
     uint32_t crc;
@@ -512,7 +512,7 @@ int ff_dovi_rpu_generate(DOVIContext *s, const AVDOVIMetadata *metadata,
         }
     }
 
-    vdr_dm_metadata_changed = !s->color || memcmp(s->color, color, sizeof(*color));
+    vdr_dm_metadata_present = memcmp(color, &ff_dovi_color_default, sizeof(*color));
     use_prev_vdr_rpu = !memcmp(&s->vdr[vdr_rpu_id]->mapping, mapping, sizeof(*mapping));
 
     buffer_size = 12 /* vdr seq info */ + 5 /* CRC32 + terminator */;
@@ -529,7 +529,7 @@ int ff_dovi_rpu_generate(DOVIContext *s, const AVDOVIMetadata *metadata,
             }
         }
     }
-    if (vdr_dm_metadata_changed)
+    if (vdr_dm_metadata_present)
         buffer_size += 67;
 
     av_fast_padded_malloc(&s->rpu_buf, &s->rpu_buf_sz, buffer_size);
@@ -560,7 +560,7 @@ int ff_dovi_rpu_generate(DOVIContext *s, const AVDOVIMetadata *metadata,
     }
     s->header = *hdr;
 
-    put_bits(pb, 1, vdr_dm_metadata_changed);
+    put_bits(pb, 1, vdr_dm_metadata_present);
     put_bits(pb, 1, use_prev_vdr_rpu);
     set_ue_golomb(pb, vdr_rpu_id);
     s->mapping = &s->vdr[vdr_rpu_id]->mapping;
@@ -632,7 +632,7 @@ int ff_dovi_rpu_generate(DOVIContext *s, const AVDOVIMetadata *metadata,
         memcpy(&s->vdr[vdr_rpu_id]->mapping, mapping, sizeof(*mapping));
     }
 
-    if (vdr_dm_metadata_changed) {
+    if (vdr_dm_metadata_present) {
         const int denom = profile == 4 ? (1 << 30) : (1 << 28);
         set_ue_golomb(pb, color->dm_metadata_id); /* affected_dm_id */
         set_ue_golomb(pb, color->dm_metadata_id); /* current_dm_id */
-- 
2.45.1

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