[FFmpeg-devel,3/3] avcodec/h264_sei: parse and export Film Grain Characteristics SEI messages

diff --git a/libavcodec/h264_sei.c b/libavcodec/h264_sei.c
index ca2ca59e1f..ad7c27f9f6 100644
--- a/libavcodec/h264_sei.c
+++ b/libavcodec/h264_sei.c
@@ -49,6 +49,7 @@  void ff_h264_sei_uninit(H264SEIContext *h)
     h->picture_timing.present      = 0;
     h->buffering_period.present    = 0;
     h->frame_packing.present       = 0;
+    h->film_grain_characteristics.present = 0;
     h->display_orientation.present = 0;
     h->afd.present                 =  0;
 
@@ -410,6 +411,49 @@  static int decode_alternative_transfer(H264SEIAlternativeTransfer *h,
     return 0;
 }
 
+static int decode_film_grain_characteristics(H264SEIFilmGrainCharacteristics *h,
+                                             GetBitContext *gb)
+{
+    int film_grain_characteristics_cancel_flag = get_bits1(gb);
+
+    if (!film_grain_characteristics_cancel_flag) {
+        memset(h, 0, sizeof(*h));
+        h->model_id = get_bits(gb, 8);
+        h->separate_colour_description_present_flag = get_bits1(gb);
+        if (h->separate_colour_description_present_flag) {
+            h->bit_depth_luma = get_bits(gb, 3) + 8;
+            h->bit_depth_chroma = get_bits(gb, 3) + 8;
+            h->full_range = get_bits1(gb);
+            h->color_primaries = get_bits(gb, 8);
+            h->transfer_characteristics = get_bits(gb, 8);
+            h->matrix_coeffs = get_bits(gb, 8);
+        }
+        h->blending_mode_id = get_bits(gb, 2);
+        h->log2_scale_factor = get_bits(gb, 4);
+        for (int c = 0; c < 3; c++)
+            h->comp_model_present_flag[c] = get_bits1(gb);
+        for (int c = 0; c < 3; c++) {
+            if (h->comp_model_present_flag[c]) {
+                h->num_intensity_intervals[c] = get_bits(gb, 8) + 1;
+                h->num_model_values[c] = get_bits(gb, 3) + 1;
+                if (h->num_model_values[c] > 6)
+                    return AVERROR_INVALIDDATA;
+                for (int i = 0; i < h->num_intensity_intervals[c]; i++) {
+                    h->intensity_interval_lower_bound[c][i] = get_bits(gb, 8);
+                    h->intensity_interval_upper_bound[c][i] = get_bits(gb, 8);
+                    for (int j = 0; j < h->num_model_values[c]; j++)
+                        h->comp_model_value[c][i][j] = get_se_golomb_long(gb);
+                }
+            }
+        }
+        h->repetition_period = get_ue_golomb_long(gb);
+
+        h->present = 1;
+    }
+
+    return 0;
+}
+
 int ff_h264_sei_decode(H264SEIContext *h, GetBitContext *gb,
                        const H264ParamSets *ps, void *logctx)
 {
@@ -471,6 +515,9 @@  int ff_h264_sei_decode(H264SEIContext *h, GetBitContext *gb,
         case SEI_TYPE_ALTERNATIVE_TRANSFER_CHARACTERISTICS:
             ret = decode_alternative_transfer(&h->alternative_transfer, &gb_payload);
             break;
+        case SEI_TYPE_FILM_GRAIN_CHARACTERISTICS:
+            ret = decode_film_grain_characteristics(&h->film_grain_characteristics, &gb_payload);
+            break;
         default:
             av_log(logctx, AV_LOG_DEBUG, "unknown SEI type %d\n", type);
         }
diff --git a/libavcodec/h264_sei.h b/libavcodec/h264_sei.h
index 14cc559361..f9166b45df 100644
--- a/libavcodec/h264_sei.h
+++ b/libavcodec/h264_sei.h
@@ -165,6 +165,27 @@  typedef struct H264SEIAlternativeTransfer {
     int preferred_transfer_characteristics;
 } H264SEIAlternativeTransfer;
 
+typedef struct H264SEIFilmGrainCharacteristics {
+    int present;
+    int model_id;
+    int separate_colour_description_present_flag;
+    int bit_depth_luma;
+    int bit_depth_chroma;
+    int full_range;
+    int color_primaries;
+    int transfer_characteristics;
+    int matrix_coeffs;
+    int blending_mode_id;
+    int log2_scale_factor;
+    int comp_model_present_flag[3];
+    uint16_t num_intensity_intervals[3];
+    uint8_t num_model_values[3];
+    uint8_t intensity_interval_lower_bound[3][256];
+    uint8_t intensity_interval_upper_bound[3][256];
+    int16_t comp_model_value[3][256][6];
+    int repetition_period;
+} H264SEIFilmGrainCharacteristics;
+
 typedef struct H264SEIContext {
     H264SEIPictureTiming picture_timing;
     H264SEIAFD afd;
@@ -176,6 +197,7 @@  typedef struct H264SEIContext {
     H264SEIDisplayOrientation display_orientation;
     H264SEIGreenMetaData green_metadata;
     H264SEIAlternativeTransfer alternative_transfer;
+    H264SEIFilmGrainCharacteristics film_grain_characteristics;
 } H264SEIContext;
 
 struct H264ParamSets;
diff --git a/libavcodec/h264_slice.c b/libavcodec/h264_slice.c
index 9c2301d7e0..0b0b779409 100644
--- a/libavcodec/h264_slice.c
+++ b/libavcodec/h264_slice.c
@@ -28,6 +28,7 @@ 
 #include "libavutil/avassert.h"
 #include "libavutil/display.h"
 #include "libavutil/imgutils.h"
+#include "libavutil/film_grain_params.h"
 #include "libavutil/stereo3d.h"
 #include "internal.h"
 #include "cabac.h"
@@ -1330,6 +1331,59 @@  static int h264_export_frame_props(H264Context *h)
     }
     h->sei.unregistered.nb_buf_ref = 0;
 
+    if (h->sei.film_grain_characteristics.present &&
+        (h->avctx->export_side_data & AV_CODEC_EXPORT_DATA_FILM_GRAIN)) {
+        H264SEIFilmGrainCharacteristics *fgc = &h->sei.film_grain_characteristics;
+        AVFilmGrainParams *fgp = av_film_grain_params_create_side_data(out);
+        if (!fgp)
+            return AVERROR(ENOMEM);
+
+        fgp->type = AV_FILM_GRAIN_PARAMS_H274;
+
+        fgp->codec.h274.model_id = fgc->model_id;
+        if (fgc->separate_colour_description_present_flag) {
+            fgp->codec.h274.bit_depth_luma = fgc->bit_depth_luma;
+            fgp->codec.h274.bit_depth_chroma = fgc->bit_depth_chroma;
+            fgp->codec.h274.color_range = fgc->full_range + 1;
+            fgp->codec.h274.color_primaries = fgc->color_primaries;
+            fgp->codec.h274.color_trc = fgc->transfer_characteristics;
+            fgp->codec.h274.color_space = fgc->matrix_coeffs;
+        } else {
+            fgp->codec.h274.bit_depth_luma = sps->bit_depth_luma;
+            fgp->codec.h274.bit_depth_chroma = sps->bit_depth_chroma;
+            if (sps->video_signal_type_present_flag)
+                fgp->codec.h274.color_range = sps->full_range + 1;
+            else
+                fgp->codec.h274.color_range = AVCOL_RANGE_UNSPECIFIED;
+            if (sps->colour_description_present_flag) {
+                fgp->codec.h274.color_primaries = sps->color_primaries;
+                fgp->codec.h274.color_trc = sps->color_trc;
+                fgp->codec.h274.color_space = sps->colorspace;
+            } else {
+                fgp->codec.h274.color_primaries = AVCOL_PRI_UNSPECIFIED;
+                fgp->codec.h274.color_trc = AVCOL_TRC_UNSPECIFIED;
+                fgp->codec.h274.color_space = AVCOL_SPC_UNSPECIFIED;
+            }
+        }
+        fgp->codec.h274.blending_mode_id = fgc->blending_mode_id;
+        fgp->codec.h274.log2_scale_factor = fgc->log2_scale_factor;
+
+        memcpy(&fgp->codec.h274.component_model_present, &fgc->comp_model_present_flag,
+               sizeof(fgp->codec.h274.component_model_present));
+        memcpy(&fgp->codec.h274.num_intensity_intervals, &fgc->num_intensity_intervals,
+               sizeof(fgp->codec.h274.num_intensity_intervals));
+        memcpy(&fgp->codec.h274.num_model_values, &fgc->num_model_values,
+               sizeof(fgp->codec.h274.num_model_values));
+        memcpy(&fgp->codec.h274.intensity_interval_lower_bound, &fgc->intensity_interval_lower_bound,
+               sizeof(fgp->codec.h274.intensity_interval_lower_bound));
+        memcpy(&fgp->codec.h274.intensity_interval_upper_bound, &fgc->intensity_interval_upper_bound,
+               sizeof(fgp->codec.h274.intensity_interval_upper_bound));
+        memcpy(&fgp->codec.h274.comp_model_value, &fgc->comp_model_value,
+               sizeof(fgp->codec.h274.comp_model_value));
+
+        fgc->present = !!fgc->repetition_period;
+    }
+
     if (h->sei.picture_timing.timecode_cnt > 0) {
         uint32_t *tc_sd;
         char tcbuf[AV_TIMECODE_STR_SIZE];