@@ -382,6 +382,14 @@ static int decode_green_metadata(H264SEIGreenMetaData *h, GetBitContext *gb)

     return 0;

 }

+static int decode_alternative_transfer(H264SEIAlternativeTransfer *h,

+                                       GetBitContext *gb)

+{

+    h->present = 1;

+    h->preferred_transfer_characteristics = get_bits(gb, 8);

+    return 0;

+}

+

 int ff_h264_sei_decode(H264SEIContext *h, GetBitContext *gb,

                        const H264ParamSets *ps, void *logctx)

 {

@@ -437,6 +445,9 @@ int ff_h264_sei_decode(H264SEIContext *h, GetBitContext *gb,

         case SEI_TYPE_GREEN_METADATA:

             ret = decode_green_metadata(&h->green_metadata, gb);

             break;

+        case SEI_TYPE_ALTERNATIVE_TRANSFER:

+            ret = decode_alternative_transfer(&h->alternative_transfer, gb);

+            break;

         default:

             av_log(logctx, AV_LOG_DEBUG, "unknown SEI type %d\n", type);

         }

@@ -32,7 +32,8 @@ typedef enum {

     SEI_TYPE_RECOVERY_POINT         = 6,   ///< recovery point (frame # to decoder sync)

     SEI_TYPE_FRAME_PACKING          = 45,  ///< frame packing arrangement

     SEI_TYPE_DISPLAY_ORIENTATION    = 47,  ///< display orientation

-    SEI_TYPE_GREEN_METADATA         = 56   ///< GreenMPEG information

+    SEI_TYPE_GREEN_METADATA         = 56,  ///< GreenMPEG information

+    SEI_TYPE_ALTERNATIVE_TRANSFER   = 147, ///< alternative transfer

 } SEI_Type;

 /**

@@ -144,6 +145,11 @@ typedef struct H264SEIGreenMetaData {

     uint16_t xsd_metric_value;

 } H264SEIGreenMetaData;

+typedef struct H264SEIAlternativeTransfer {

+    int present;

+    int preferred_transfer_characteristics;

+} H264SEIAlternativeTransfer;

+

 typedef struct H264SEIContext {

     H264SEIPictureTiming picture_timing;

     H264SEIAFD afd;

@@ -154,6 +160,7 @@ typedef struct H264SEIContext {

     H264SEIFramePacking frame_packing;

     H264SEIDisplayOrientation display_orientation;

     H264SEIGreenMetaData green_metadata;

+    H264SEIAlternativeTransfer alternative_transfer;

 } H264SEIContext;

 struct H264ParamSets;

@@ -1287,6 +1287,12 @@ static int h264_export_frame_props(H264Context *h)

         h->avctx->properties |= FF_CODEC_PROPERTY_CLOSED_CAPTIONS;

     }

+    if (h->sei.alternative_transfer.present &&

+        av_color_transfer_name(h->sei.alternative_transfer.preferred_transfer_characteristics) &&

+        h->sei.alternative_transfer.preferred_transfer_characteristics != AVCOL_TRC_UNSPECIFIED) {

+        h->avctx->color_trc = cur->f->color_trc = h->sei.alternative_transfer.preferred_transfer_characteristics;

+    }

+

     return 0;

 }