libavutil: add mastering display metadata sidedata

Adding mastering display metadata struct to avutil. The mastering display metadata contains information
about the mastering display color volume (SMPTE 2086:2014).

This info comes from HEVC in the SEI_TYPE_MASTERING_DISPLAY_INFO and is soon to be included in MKV:
https://mailarchive.ietf.org/arch/search/?email_list=cellar&gbt=1&index=sZyfPTM-QY69P-0omfOIiTN622o
so it is similar to SEI FPA / stereo_mode in MKV and as such this patch follows how AVStereo3D is implemented.

I'll add support to HEVC in a follow-up (and MKV when spec is approved).
Signed-off-by: Neil Birkbeck <neil.birkbeck@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavutil/Makefile

@@ -38,6 +38,7 @@ HEADERS = adler32.h                                                     \
           log.h                                                         \
           macros.h                                                      \
           mathematics.h                                                 \
+          mastering_display_metadata.h                                  \
           md5.h                                                         \
           mem.h                                                         \
           motion_vector.h                                               \
@@ -115,6 +116,7 @@ OBJS = adler32.o                                                        \
        log.o                                                            \
        log2_tab.o                                                       \
        mathematics.o                                                    \
+       mastering_display_metadata.o                                     \
        md5.o                                                            \
        mem.o                                                            \
        murmur3.o                                                        \

libavutil/frame.h

@@ -106,12 +106,17 @@ enum AVFrameSideDataType {
      * @endcode
      */
     AV_FRAME_DATA_SKIP_SAMPLES,
-
     /**
      * This side data must be associated with an audio frame and corresponds to
      * enum AVAudioServiceType defined in avcodec.h.
      */
     AV_FRAME_DATA_AUDIO_SERVICE_TYPE,
+    /**
+     * Mastering display metadata associated with a video frame. The payload is
+     * an AVMasteringDisplayMetadata type and contains information about the
+     * mastering display color volume.
+     */
+    AV_FRAME_DATA_MASTERING_DISPLAY_METADATA
 };
 
 enum AVActiveFormatDescription {

libavutil/mastering_display_metadata.c

+/**
+ * Copyright (c) 2016 Neil Birkbeck <neil.birkbeck@gmail.com>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <stdint.h>
+#include <string.h>
+
+#include "mastering_display_metadata.h"
+#include "mem.h"
+
+AVMasteringDisplayMetadata *av_mastering_display_metadata_alloc(void)
+{
+    return av_mallocz(sizeof(AVMasteringDisplayMetadata));
+}
+
+AVMasteringDisplayMetadata *av_mastering_display_metadata_create_side_data(AVFrame *frame)
+{
+    AVFrameSideData *side_data = av_frame_new_side_data(frame,
+                                                        AV_FRAME_DATA_MASTERING_DISPLAY_METADATA,
+                                                        sizeof(AVMasteringDisplayMetadata));
+    if (!side_data)
+        return NULL;
+
+    memset(side_data->data, 0, sizeof(AVMasteringDisplayMetadata));
+
+    return (AVMasteringDisplayMetadata *)side_data->data;
+}

libavutil/mastering_display_metadata.h

+/**
+ * Copyright (c) 2016 Neil Birkbeck <neil.birkbeck@gmail.com>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVUTIL_MASTERING_DISPLAY_METADATA_H
+#define AVUTIL_MASTERING_DISPLAY_METADATA_H
+
+#include "frame.h"
+
+/**
+ * Mastering display metadata capable of representing the color volume of
+ * the display used to master the content (SMPTE 2086:2014).
+ *
+ * To be used as payload of a AVFrameSideData or AVPacketSideData with the
+ * appropriate type.
+ *
+ * @note The struct should be allocated with av_mastering_display_metadata_alloc()
+ *       and its size is not a part of the public ABI.
+ */
+typedef struct AVMasteringDisplayMetadata {
+    /**
+     * CIE 1931 xy chromaticity coords of color primaries (r, g, b order).
+     */
+    float display_primaries[3][2];
+
+    /**
+     * CIE 1931 xy chromaticity coords of white point.
+     */
+    float white_point[2];
+
+    /**
+     * Min luminance of mastering display (cd/m^2).
+     */
+    float min_luminance;
+
+    /**
+     * Max luminance of mastering display (cd/m^2).
+     */
+    float max_luminance;
+
+    /**
+     * Flag indicating whether the display primaries (and white point) are set.
+     */
+    int has_primaries;
+
+    /**
+     * Flag indicating whether the luminance (min_ and max_) have been set.
+     */
+    int has_luminance;
+
+} AVMasteringDisplayMetadata;
+
+/**
+ * Allocate an AVMasteringDisplayMetadata structure and set its fields to
+ * default values. The resulting struct can be freed using av_freep().
+ *
+ * @return An AVMasteringDisplayMetadata filled with default values or NULL
+ *         on failure.
+ */
+AVMasteringDisplayMetadata *av_mastering_display_metadata_alloc(void);
+
+/**
+ * Allocate a complete AVMasteringDisplayMetadata and add it to the frame.
+ *
+ * @param frame The frame which side data is added to.
+ *
+ * @return The AVMasteringDisplayMetadata structure to be filled by caller.
+ */
+AVMasteringDisplayMetadata *av_mastering_display_metadata_create_side_data(AVFrame *frame);
+
+#endif /* AVUTIL_MASTERING_DISPLAY_METADATA_H */

libavutil/version.h

@@ -64,7 +64,7 @@
  */
 
 #define LIBAVUTIL_VERSION_MAJOR  55
-#define LIBAVUTIL_VERSION_MINOR  13
+#define LIBAVUTIL_VERSION_MINOR  14
 #define LIBAVUTIL_VERSION_MICRO 100
 
 #define LIBAVUTIL_VERSION_INT   AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \