lavc/hevc Parse SEI_TYPE_MASTERING_DISPLAY_INFO and propagate content into the AVMasteringDisplayMetadata side data.

Add support for parsing SEI_TYPE_MASTERING_DISPLAY_INFO and propagate contents into
the AVMasteringDisplayMetadata side data. Primaries are ordered in RGB order and
the values are converted to rationals ([0,1] for CEI 1931 Chroma coords,
and cd/m^2 for luma).

Signed-off-by: Neil Birkbeck <neil.birkbeck@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/hevc.c

@@ -28,6 +28,7 @@
 #include "libavutil/common.h"
 #include "libavutil/display.h"
 #include "libavutil/internal.h"
+#include "libavutil/mastering_display_metadata.h"
 #include "libavutil/md5.h"
 #include "libavutil/opt.h"
 #include "libavutil/pixdesc.h"
@@ -2580,6 +2581,57 @@ static int set_side_data(HEVCContext *s)
                                s->sei_hflip, s->sei_vflip);
     }
 
+    // Decrement the mastering display flag when IRAP frame has no_rasl_output_flag=1
+    // so the side data persists for the entire coded video sequence.
+    if (s->sei_mastering_display_info_present > 0 &&
+        IS_IRAP(s) && s->no_rasl_output_flag) {
+        s->sei_mastering_display_info_present--;
+    }
+    if (s->sei_mastering_display_info_present) {
+        // HEVC uses a g,b,r ordering, which we convert to a more natural r,g,b
+        const int mapping[3] = {2, 0, 1};
+        const int chroma_den = 50000;
+        const int luma_den = 10000;
+        int i;
+        AVMasteringDisplayMetadata *metadata =
+            av_mastering_display_metadata_create_side_data(out);
+        if (!metadata)
+            return AVERROR(ENOMEM);
+
+        for (i = 0; i < 3; i++) {
+            const int j = mapping[i];
+            metadata->display_primaries[i][0].num = s->display_primaries[j][0];
+            metadata->display_primaries[i][0].den = chroma_den;
+            metadata->display_primaries[i][1].num = s->display_primaries[j][1];
+            metadata->display_primaries[i][1].den = chroma_den;
+        }
+        metadata->white_point[0].num = s->white_point[0];
+        metadata->white_point[0].den = chroma_den;
+        metadata->white_point[1].num = s->white_point[1];
+        metadata->white_point[1].den = chroma_den;
+
+        metadata->max_luminance.num = s->max_mastering_luminance;
+        metadata->max_luminance.den = luma_den;
+        metadata->min_luminance.num = s->min_mastering_luminance;
+        metadata->min_luminance.den = luma_den;
+        metadata->has_luminance = 1;
+        metadata->has_primaries = 1;
+
+        av_log(s->avctx, AV_LOG_DEBUG, "Mastering Display Metadata:\n");
+        av_log(s->avctx, AV_LOG_DEBUG,
+               "r(%5.4f,%5.4f) g(%5.4f,%5.4f) b(%5.4f %5.4f) wp(%5.4f, %5.4f)\n",
+               av_q2d(metadata->display_primaries[0][0]),
+               av_q2d(metadata->display_primaries[0][1]),
+               av_q2d(metadata->display_primaries[1][0]),
+               av_q2d(metadata->display_primaries[1][1]),
+               av_q2d(metadata->display_primaries[2][0]),
+               av_q2d(metadata->display_primaries[2][1]),
+               av_q2d(metadata->white_point[0]), av_q2d(metadata->white_point[1]));
+        av_log(s->avctx, AV_LOG_DEBUG,
+               "min_luminance=%f, max_luminance=%f\n",
+               av_q2d(metadata->min_luminance), av_q2d(metadata->max_luminance));
+    }
+
     if (s->a53_caption) {
         AVFrameSideData* sd = av_frame_new_side_data(out,
                                                      AV_FRAME_DATA_A53_CC,

libavcodec/hevc.h

@@ -941,6 +941,13 @@ typedef struct HEVCContext {
     uint8_t* a53_caption;
     int a53_caption_size;
 
+    /** mastering display */
+    int sei_mastering_display_info_present;
+    uint16_t display_primaries[3][2];
+    uint16_t white_point[2];
+    uint32_t max_mastering_luminance;
+    uint32_t min_mastering_luminance;
+
 } HEVCContext;
 
 int ff_hevc_decode_short_term_rps(GetBitContext *gb, AVCodecContext *avctx,

libavcodec/hevc_sei.c

@@ -78,6 +78,30 @@ static int decode_nal_sei_decoded_picture_hash(HEVCContext *s)
     return 0;
 }
 
+static int decode_nal_sei_mastering_display_info(HEVCContext *s)
+{
+    GetBitContext *gb = &s->HEVClc->gb;
+    int i;
+    // Mastering primaries
+    for (i = 0; i < 3; i++) {
+        s->display_primaries[i][0] = get_bits(gb, 16);
+        s->display_primaries[i][1] = get_bits(gb, 16);
+    }
+    // White point (x, y)
+    s->white_point[0] = get_bits(gb, 16);
+    s->white_point[1] = get_bits(gb, 16);
+
+    // Max and min luminance of mastering display
+    s->max_mastering_luminance = get_bits_long(gb, 32);
+    s->min_mastering_luminance = get_bits_long(gb, 32);
+
+    // As this SEI message comes before the first frame that references it,
+    // initialize the flag to 2 and decrement on IRAP access unit so it
+    // persists for the coded video sequence (e.g., between two IRAPs)
+    s->sei_mastering_display_info_present = 2;
+    return 0;
+}
+
 static int decode_nal_sei_frame_packing_arrangement(HEVCContext *s)
 {
     GetBitContext *gb = &s->HEVClc->gb;
@@ -278,6 +302,8 @@ static int decode_nal_sei_prefix(HEVCContext *s, int type, int size)
             skip_bits(gb, 8 * size);
             return ret;
         }
+    case SEI_TYPE_MASTERING_DISPLAY_INFO:
+        return decode_nal_sei_mastering_display_info(s);
     case SEI_TYPE_ACTIVE_PARAMETER_SETS:
         active_parameter_sets(s);
         av_log(s->avctx, AV_LOG_DEBUG, "Skipped PREFIX SEI %d\n", type);