[FFmpeg-devel] [PATCH v4] pngdec: expose gAMA and cHRM chunks as side/meta data

[Rostislav Pehlivanov]

Signed-off-by: Rostislav Pehlivanov <atomnuker at gmail.com>
---
 libavcodec/pngdec.c | 30 +++++++++++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/libavcodec/pngdec.c b/libavcodec/pngdec.c
index 0d6612ccca..aef0d95819 100644
--- a/libavcodec/pngdec.c
+++ b/libavcodec/pngdec.c
@@ -25,6 +25,7 @@
 #include "libavutil/bprint.h"
 #include "libavutil/imgutils.h"
 #include "libavutil/stereo3d.h"
+#include "libavutil/mastering_display_metadata.h"
 
 #include "avcodec.h"
 #include "bytestream.h"
@@ -1165,7 +1166,7 @@ static int decode_frame_common(AVCodecContext *avctx, PNGDecContext *s,
     AVDictionary **metadatap = NULL;
     uint32_t tag, length;
     int decode_next_dat = 0;
-    int ret;
+    int i, ret;
 
     for (;;) {
         length = bytestream2_get_bytes_left(&s->gb);
@@ -1287,6 +1288,33 @@ static int decode_frame_common(AVCodecContext *avctx, PNGDecContext *s,
                 goto fail;
             break;
         }
+        case MKTAG('c', 'H', 'R', 'M'): {
+            AVMasteringDisplayMetadata *mdm = av_mastering_display_metadata_create_side_data(p);
+            if (!mdm) {
+                ret = AVERROR(ENOMEM);
+                goto fail;
+            }
+
+            mdm->white_point[0] = av_make_q(bytestream2_get_be32(&s->gb), 100000);
+            mdm->white_point[1] = av_make_q(bytestream2_get_be32(&s->gb), 100000);
+
+            /* RGB Primaries */
+            for (i = 0; i < 3; i++) {
+                mdm->display_primaries[i][0] = av_make_q(bytestream2_get_be32(&s->gb), 100000);
+                mdm->display_primaries[i][1] = av_make_q(bytestream2_get_be32(&s->gb), 100000);
+            }
+
+            mdm->has_primaries = 1;
+            bytestream2_skip(&s->gb, 4); /* crc */
+            break;
+        }
+        case MKTAG('g', 'A', 'M', 'A'): {
+            av_dict_set_int(&p->metadata, "gamma_num", bytestream2_get_be32(&s->gb), 0);
+            av_dict_set_int(&p->metadata, "gamma_den", 100000, 0);
+
+            bytestream2_skip(&s->gb, 4); /* crc */
+            break;
+        }
         case MKTAG('I', 'E', 'N', 'D'):
             if (!(s->pic_state & PNG_ALLIMAGE))
                 av_log(avctx, AV_LOG_ERROR, "IEND without all image\n");
-- 
2.15.0.448.gf294e3d99a