diff --git a/libavutil/hdr_dynamic_metadata.c b/libavutil/hdr_dynamic_metadata.c
index 0fa1ee82de..fbab192c62 100644
--- a/libavutil/hdr_dynamic_metadata.c
+++ b/libavutil/hdr_dynamic_metadata.c
@@ -1,4 +1,4 @@
-/**
+ /**
  * Copyright (c) 2018 Mohammad Izadi <moh.izadi at gmail.com>
  *
  * This file is part of FFmpeg.
@@ -21,6 +21,14 @@
 #include "hdr_dynamic_metadata.h"
 #include "mem.h"
 
+static const int64_t luminance_den = 1;
+static const int32_t peak_luminance_den = 15;
+static const int64_t rgb_den = 100000;
+static const int32_t fraction_pixel_den = 1000;
+static const int32_t knee_point_den = 4095;
+static const int32_t bezier_anchor_den = 1023;
+static const int32_t saturation_weight_den = 8;
+
 AVDynamicHDRPlus *av_dynamic_hdr_plus_alloc(size_t *size)
 {
     AVDynamicHDRPlus *hdr_plus = av_mallocz(sizeof(AVDynamicHDRPlus));
@@ -45,3 +53,160 @@ AVDynamicHDRPlus *av_dynamic_hdr_plus_create_side_data(AVFrame *frame)
 
     return (AVDynamicHDRPlus *)side_data->data;
 }
+
+int av_dynamic_hdr_plus_decode(const uint8_t *data, size_t size,
+			       AVDynamicHDRPlus *s)
+{
+    int w, i, j;
+    GetBitContext gb;
+    if(!data)
+        return AVERROR_INVALIDDATA;
+    
+    int ret = init_get_bits8(&gb, data, size);
+    if(ret < 0)
+        return AVERROR_INVALIDDATA;
+
+    if (get_bits_left(&gb) < 2)
+        return AVERROR_INVALIDDATA;
+    s->num_windows = get_bits(&gb, 2);
+
+    if (s->num_windows < 1 || s->num_windows > 3) {
+        return AVERROR_INVALIDDATA;
+    }
+
+    if (get_bits_left(&gb) < ((19 * 8 + 1) * (s->num_windows - 1)))
+        return AVERROR_INVALIDDATA;
+    for (w = 1; w < s->num_windows; w++) {
+        s->params[w].window_upper_left_corner_x.num = get_bits(&gb, 16);
+        s->params[w].window_upper_left_corner_y.num = get_bits(&gb, 16);
+        s->params[w].window_lower_right_corner_x.num = get_bits(&gb, 16);
+        s->params[w].window_lower_right_corner_y.num = get_bits(&gb, 16);
+        // The corners are set to absolute coordinates here. They should be
+        // converted to the relative coordinates (in [0, 1]) in the decoder.
+        s->params[w].window_upper_left_corner_x.den = 1;
+        s->params[w].window_upper_left_corner_y.den = 1;
+        s->params[w].window_lower_right_corner_x.den = 1;
+        s->params[w].window_lower_right_corner_y.den = 1;
+
+        s->params[w].center_of_ellipse_x = get_bits(&gb, 16);
+        s->params[w].center_of_ellipse_y = get_bits(&gb, 16);
+        s->params[w].rotation_angle = get_bits(&gb, 8);
+        s->params[w].semimajor_axis_internal_ellipse = get_bits(&gb, 16);
+        s->params[w].semimajor_axis_external_ellipse = get_bits(&gb, 16);
+        s->params[w].semiminor_axis_external_ellipse = get_bits(&gb, 16);
+        s->params[w].overlap_process_option = get_bits1(&gb);
+    }
+
+    if (get_bits_left(&gb) < 28)
+        return AVERROR(EINVAL);
+    s->targeted_system_display_maximum_luminance.num = get_bits(&gb, 27);
+    s->targeted_system_display_maximum_luminance.den = luminance_den;
+    s->targeted_system_display_actual_peak_luminance_flag = get_bits1(&gb);
+
+    if (s->targeted_system_display_actual_peak_luminance_flag) {
+        int rows, cols;
+        if (get_bits_left(&gb) < 10)
+            return AVERROR(EINVAL);
+        rows = get_bits(&gb, 5);
+        cols = get_bits(&gb, 5);
+        if (((rows < 2) || (rows > 25)) || ((cols < 2) || (cols > 25))) {
+            return AVERROR_INVALIDDATA;
+        }
+        s->num_rows_targeted_system_display_actual_peak_luminance = rows;
+        s->num_cols_targeted_system_display_actual_peak_luminance = cols;
+
+        if (get_bits_left(&gb) < (rows * cols * 4))
+            return AVERROR(EINVAL);
+
+        for (i = 0; i < rows; i++) {
+            for (j = 0; j < cols; j++) {
+                s->targeted_system_display_actual_peak_luminance[i][j].num = get_bits(&gb, 4);
+                s->targeted_system_display_actual_peak_luminance[i][j].den = peak_luminance_den;
+            }
+        }
+    }
+    for (w = 0; w < s->num_windows; w++) {
+        if (get_bits_left(&gb) < (3 * 17 + 17 + 4))
+            return AVERROR(EINVAL);
+        for (i = 0; i < 3; i++) {
+            s->params[w].maxscl[i].num = get_bits(&gb, 17);
+            s->params[w].maxscl[i].den = rgb_den;
+        }
+        s->params[w].average_maxrgb.num = get_bits(&gb, 17);
+        s->params[w].average_maxrgb.den = rgb_den;
+        s->params[w].num_distribution_maxrgb_percentiles = get_bits(&gb, 4);
+
+        if (get_bits_left(&gb) <
+            (s->params[w].num_distribution_maxrgb_percentiles * 24))
+            return AVERROR(EINVAL);
+        for (i = 0; i < s->params[w].num_distribution_maxrgb_percentiles; i++) {
+            s->params[w].distribution_maxrgb[i].percentage = get_bits(&gb, 7);
+            s->params[w].distribution_maxrgb[i].percentile.num = get_bits(&gb, 17);
+            s->params[w].distribution_maxrgb[i].percentile.den = rgb_den;
+        }
+
+        if (get_bits_left(&gb) < 10)
+            return AVERROR(EINVAL);
+        s->params[w].fraction_bright_pixels.num = get_bits(&gb, 10);
+        s->params[w].fraction_bright_pixels.den = fraction_pixel_den;
+    }
+    if (get_bits_left(&gb) < 1)
+        return AVERROR(EINVAL);
+    s->mastering_display_actual_peak_luminance_flag = get_bits1(&gb);
+    if (s->mastering_display_actual_peak_luminance_flag) {
+        int rows, cols;
+        if (get_bits_left(&gb) < 10)
+            return AVERROR(EINVAL);
+        rows = get_bits(&gb, 5);
+        cols = get_bits(&gb, 5);
+        if (((rows < 2) || (rows > 25)) || ((cols < 2) || (cols > 25))) {
+            return AVERROR_INVALIDDATA;
+        }
+        s->num_rows_mastering_display_actual_peak_luminance = rows;
+        s->num_cols_mastering_display_actual_peak_luminance = cols;
+
+        if (get_bits_left(&gb) < (rows * cols * 4))
+            return AVERROR(EINVAL);
+
+        for (i = 0; i < rows; i++) {
+            for (j = 0; j < cols; j++) {
+                s->mastering_display_actual_peak_luminance[i][j].num = get_bits(&gb, 4);
+                s->mastering_display_actual_peak_luminance[i][j].den = peak_luminance_den;
+            }
+        }
+    }
+
+    for (w = 0; w < s->num_windows; w++) {
+        if (get_bits_left(&gb) < 1)
+            return AVERROR(EINVAL);
+        s->params[w].tone_mapping_flag = get_bits1(&gb);
+        if (s->params[w].tone_mapping_flag) {
+            if (get_bits_left(&gb) < 28)
+                return AVERROR(EINVAL);
+            s->params[w].knee_point_x.num = get_bits(&gb, 12);
+            s->params[w].knee_point_x.den = knee_point_den;
+            s->params[w].knee_point_y.num = get_bits(&gb, 12);
+            s->params[w].knee_point_y.den = knee_point_den;
+            s->params[w].num_bezier_curve_anchors = get_bits(&gb, 4);
+
+            if (get_bits_left(&gb) < (s->params[w].num_bezier_curve_anchors * 10))
+                return AVERROR(EINVAL);
+            for (i = 0; i < s->params[w].num_bezier_curve_anchors; i++) {
+                s->params[w].bezier_curve_anchors[i].num = get_bits(&gb, 10);
+                s->params[w].bezier_curve_anchors[i].den = bezier_anchor_den;
+            }
+        }
+
+        if (get_bits_left(&gb) < 1)
+            return AVERROR(EINVAL);
+        s->params[w].color_saturation_mapping_flag = get_bits1(&gb);
+        if (s->params[w].color_saturation_mapping_flag) {
+            if (get_bits_left(&gb) < 6)
+                return AVERROR(EINVAL);
+            s->params[w].color_saturation_weight.num = get_bits(&gb, 6);
+            s->params[w].color_saturation_weight.den = saturation_weight_den;
+        }
+    }
+
+    return 0;
+}
diff --git a/libavutil/hdr_dynamic_metadata.h b/libavutil/hdr_dynamic_metadata.h
index 2d72de56ae..0fc070b078 100644
--- a/libavutil/hdr_dynamic_metadata.h
+++ b/libavutil/hdr_dynamic_metadata.h
@@ -23,6 +23,8 @@
 
 #include "frame.h"
 #include "rational.h"
+#include "libavcodec/get_bits.h"
+#include "libavcodec/put_bits.h"
 
 /**
  * Option for overlapping elliptical pixel selectors in an image.
@@ -265,7 +267,7 @@ typedef struct AVDynamicHDRPlus {
 
     /**
      * The nominal maximum display luminance of the targeted system display,
-     * in units of 0.0001 candelas per square metre. The value shall be in
+     * in units of 1 candelas per square metre. The value shall be in
      * the range of 0 to 10000, inclusive.
      */
     AVRational targeted_system_display_maximum_luminance;
@@ -340,4 +342,14 @@ AVDynamicHDRPlus *av_dynamic_hdr_plus_alloc(size_t *size);
  */
 AVDynamicHDRPlus *av_dynamic_hdr_plus_create_side_data(AVFrame *frame);
 
+/**
+ * Decode SMPTE ST 2094-40 (the user data registered ITU-T T.35) to AVDynamicHDRPlus.
+ * @param data The user data registered ITU-T T.35 (SMPTE ST 2094-40).
+ * @param size The size of the user data registered ITU-T T.35 (SMPTE ST 2094-40).
+ * @param s The decoded AVDynamicHDRPlus structure.
+ *
+ * @return 0 if succeed. Otherwise, returns the appropriate AVERROR.
+ */
+int av_dynamic_hdr_plus_decode(const uint8_t *data, size_t size, AVDynamicHDRPlus *s);
+
 #endif /* AVUTIL_HDR_DYNAMIC_METADATA_H */
diff --git a/libavutil/version.h b/libavutil/version.h
index af8f614aff..2bc1b98615 100644
--- a/libavutil/version.h
+++ b/libavutil/version.h
@@ -79,7 +79,7 @@
  */
 
 #define LIBAVUTIL_VERSION_MAJOR  56
-#define LIBAVUTIL_VERSION_MINOR  38
+#define LIBAVUTIL_VERSION_MINOR  39
 #define LIBAVUTIL_VERSION_MICRO 100
 
 #define LIBAVUTIL_VERSION_INT   AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \
