[FFmpeg-devel] [PATCH] hevc: Add support for alternative transfer characterics SEI

[Vittorio Giovara]

Signed-off-by: Vittorio Giovara <vittorio.giovara at gmail.com>
---
 libavcodec/hevc_sei.c | 9 +++++++++
 libavcodec/hevc_sei.h | 7 +++++++
 libavcodec/hevcdec.c  | 5 +++++
 3 files changed, 21 insertions(+)

diff --git a/libavcodec/hevc_sei.c b/libavcodec/hevc_sei.c
index f0ad84f2f4..cd55d50212 100644
--- a/libavcodec/hevc_sei.c
+++ b/libavcodec/hevc_sei.c
@@ -265,6 +265,13 @@ static int decode_nal_sei_active_parameter_sets(HEVCSEIContext *s, GetBitContext
     return 0;
 }
 
+static int decode_nal_sei_alternative_transfer(HEVCSEIAlternativeTransfer *s, GetBitContext *gb)
+{
+    s->present = 1;
+    s->preferred_transfer_characteristics = get_bits(gb, 8);
+    return 0;
+}
+
 static int decode_nal_sei_prefix(GetBitContext *gb, HEVCSEIContext *s, const HEVCParamSets *ps,
                                  int type, int size, void *logctx)
 {
@@ -285,6 +292,8 @@ static int decode_nal_sei_prefix(GetBitContext *gb, HEVCSEIContext *s, const HEV
         return decode_nal_sei_active_parameter_sets(s, gb, logctx);
     case HEVC_SEI_TYPE_USER_DATA_REGISTERED_ITU_T_T35:
         return decode_nal_sei_user_data_registered_itu_t_t35(s, gb, size);
+    case HEVC_SEI_TYPE_ALTERNATIVE_TRANSFER_CHARACTERISTICS:
+        return decode_nal_sei_alternative_transfer(&s->alternative_transfer, gb);
     default:
         av_log(logctx, AV_LOG_DEBUG, "Skipped PREFIX SEI %d\n", type);
         skip_bits_long(gb, 8 * size);
diff --git a/libavcodec/hevc_sei.h b/libavcodec/hevc_sei.h
index 5645e4f5de..1b522227ec 100644
--- a/libavcodec/hevc_sei.h
+++ b/libavcodec/hevc_sei.h
@@ -56,6 +56,7 @@ typedef enum {
     HEVC_SEI_TYPE_REGION_REFRESH_INFO                  = 134,
     HEVC_SEI_TYPE_MASTERING_DISPLAY_INFO               = 137,
     HEVC_SEI_TYPE_CONTENT_LIGHT_LEVEL_INFO             = 144,
+    HEVC_SEI_TYPE_ALTERNATIVE_TRANSFER_CHARACTERISTICS = 147,
 } HEVC_SEI_Type;
 
 typedef struct HEVCSEIPictureHash {
@@ -100,6 +101,11 @@ typedef struct HEVCSEIContentLight {
     uint16_t max_pic_average_light_level;
 } HEVCSEIContentLight;
 
+typedef struct HEVCSEIAlternativeTransfer {
+    int present;
+    int preferred_transfer_characteristics;
+} HEVCSEIAlternativeTransfer;
+
 typedef struct HEVCSEIContext {
     HEVCSEIPictureHash picture_hash;
     HEVCSEIFramePacking frame_packing;
@@ -109,6 +115,7 @@ typedef struct HEVCSEIContext {
     HEVCSEIMasteringDisplay mastering_display;
     HEVCSEIContentLight content_light;
     int active_seq_parameter_set_id;
+    HEVCSEIAlternativeTransfer alternative_transfer;
 } HEVCSEIContext;
 
 struct HEVCParamSets;
diff --git a/libavcodec/hevcdec.c b/libavcodec/hevcdec.c
index 23a89345a8..955cc703cf 100644
--- a/libavcodec/hevcdec.c
+++ b/libavcodec/hevcdec.c
@@ -2684,6 +2684,11 @@ static int set_side_data(HEVCContext *s)
         s->avctx->properties |= FF_CODEC_PROPERTY_CLOSED_CAPTIONS;
     }
 
+    if (s->sei.alternative_transfer.present &&
+        s->sei.alternative_transfer.preferred_transfer_characteristics != AVCOL_SPC_UNSPECIFIED) {
+        s->avctx->color_trc = s->sei.alternative_transfer.preferred_transfer_characteristics;
+    }
+
     return 0;
 }
 
-- 
2.12.0