diff --git a/libavcodec/h2645_sei.c b/libavcodec/h2645_sei.c
index c46a563308..33551f5406 100644
--- a/libavcodec/h2645_sei.c
+++ b/libavcodec/h2645_sei.c
@@ -245,7 +245,12 @@ static int decode_registered_user_data(H2645SEI *h, GetByteContext *gb,
 
         provider_oriented_code = bytestream2_get_byteu(gb);
         if (provider_oriented_code == aom_grain_provider_oriented_code) {
-            return ff_aom_parse_film_grain_sets(&h->aom_film_grain,
+            if (!h->aom_film_grain) {
+                h->aom_film_grain = av_mallocz(sizeof(*h->aom_film_grain));
+                if (!h->aom_film_grain)
+                    return AVERROR(ENOMEM);
+            }
+            return ff_aom_parse_film_grain_sets(h->aom_film_grain,
                                                 gb->buffer,
                                                 bytestream2_get_bytes_left(gb));
         }
@@ -494,7 +499,12 @@ int ff_h2645_sei_message_decode(H2645SEI *h, enum SEIType type,
     case SEI_TYPE_DISPLAY_ORIENTATION:
         return decode_display_orientation(&h->display_orientation, gb);
     case SEI_TYPE_FILM_GRAIN_CHARACTERISTICS:
-        return decode_film_grain_characteristics(&h->film_grain_characteristics, codec_id, gb);
+        if (!h->film_grain_characteristics) {
+            h->film_grain_characteristics = av_mallocz(sizeof(*h->film_grain_characteristics));
+            if (!h->film_grain_characteristics)
+                return AVERROR(ENOMEM);
+        }
+        return decode_film_grain_characteristics(h->film_grain_characteristics, codec_id, gb);
     case SEI_TYPE_FRAME_PACKING_ARRANGEMENT:
         return decode_frame_packing_arrangement(&h->frame_packing, gb, codec_id);
     case SEI_TYPE_ALTERNATIVE_TRANSFER_CHARACTERISTICS:
@@ -811,8 +821,8 @@ int ff_h2645_sei_to_frame(AVFrame *frame, H2645SEI *sei,
             return ret;
     }
 
-    if (sei->film_grain_characteristics.present) {
-        H2645SEIFilmGrainCharacteristics *fgc = &sei->film_grain_characteristics;
+    if (sei->film_grain_characteristics && sei->film_grain_characteristics->present) {
+        H2645SEIFilmGrainCharacteristics *fgc = sei->film_grain_characteristics;
         AVFilmGrainParams *fgp = av_film_grain_params_create_side_data(frame);
         AVFilmGrainH274Params *h274;
 
@@ -884,9 +894,11 @@ FF_ENABLE_DEPRECATION_WARNINGS
     }
 
 #if CONFIG_HEVC_SEI
-    ret = ff_aom_attach_film_grain_sets(&sei->aom_film_grain, frame);
-    if (ret < 0)
-        return ret;
+    if (sei->aom_film_grain) {
+        ret = ff_aom_attach_film_grain_sets(sei->aom_film_grain, frame);
+        if (ret < 0)
+            return ret;
+    }
 #endif
 
     return 0;
@@ -913,5 +925,7 @@ void ff_h2645_sei_reset(H2645SEI *s)
     s->ambient_viewing_environment.present = 0;
     s->mastering_display.present = 0;
     s->content_light.present = 0;
-    s->aom_film_grain.enable = 0;
+
+    av_freep(&s->film_grain_characteristics);
+    av_freep(&s->aom_film_grain);
 }
diff --git a/libavcodec/h2645_sei.h b/libavcodec/h2645_sei.h
index 598f78b585..8bcdc2bc5f 100644
--- a/libavcodec/h2645_sei.h
+++ b/libavcodec/h2645_sei.h
@@ -135,11 +135,13 @@ typedef struct H2645SEI {
     H2645SEIFramePacking frame_packing;
     H2645SEIDisplayOrientation display_orientation;
     H2645SEIAlternativeTransfer alternative_transfer;
-    H2645SEIFilmGrainCharacteristics film_grain_characteristics;
     H2645SEIAmbientViewingEnvironment ambient_viewing_environment;
     H2645SEIMasteringDisplay mastering_display;
     H2645SEIContentLight content_light;
-    AVFilmGrainAFGS1Params aom_film_grain;
+
+    // Dynamic allocations due to large size.
+    H2645SEIFilmGrainCharacteristics* film_grain_characteristics;
+    AVFilmGrainAFGS1Params* aom_film_grain;
 } H2645SEI;
 
 enum {
diff --git a/libavcodec/h264_picture.c b/libavcodec/h264_picture.c
index 3234141dbd..371a794ec2 100644
--- a/libavcodec/h264_picture.c
+++ b/libavcodec/h264_picture.c
@@ -27,6 +27,7 @@
 
 #include "libavutil/avassert.h"
 #include "libavutil/emms.h"
+#include "libavutil/mem.h"
 #include "error_resilience.h"
 #include "avcodec.h"
 #include "h264dec.h"
@@ -212,9 +213,15 @@ int ff_h264_field_end(H264Context *h, H264SliceContext *sl, int in_setup)
         const AVFrameSideData *sd = av_frame_get_side_data(cur->f, AV_FRAME_DATA_FILM_GRAIN_PARAMS);
 
         err = AVERROR_INVALIDDATA;
-        if (sd) // a decoding error may have happened before the side data could be allocated
-            err = ff_h274_apply_film_grain(cur->f_grain, cur->f, &h->h274db,
+        if (sd) { // a decoding error may have happened before the side data could be allocated
+            if (!h->h274db) {
+                h->h274db = av_mallocz(sizeof(*h->h274db));
+                if (!h->h274db)
+                    return AVERROR(ENOMEM);
+            }
+            err = ff_h274_apply_film_grain(cur->f_grain, cur->f, h->h274db,
                                            (AVFilmGrainParams *) sd->data);
+        }
         if (err < 0) {
             av_log(h->avctx, AV_LOG_WARNING, "Failed synthesizing film "
                    "grain, ignoring: %s\n", av_err2str(err));
diff --git a/libavcodec/h264_sei.c b/libavcodec/h264_sei.c
index 8d6dc77943..15a5232209 100644
--- a/libavcodec/h264_sei.c
+++ b/libavcodec/h264_sei.c
@@ -55,7 +55,6 @@ void ff_h264_sei_uninit(H264SEIContext *h)
     h->picture_timing.present      = 0;
     h->buffering_period.present    = 0;
     h->common.frame_packing.present       = 0;
-    h->common.film_grain_characteristics.present = 0;
     h->common.display_orientation.present = 0;
     h->common.afd.present                 =  0;
 
diff --git a/libavcodec/h264_slice.c b/libavcodec/h264_slice.c
index a66b75ca80..84595b1a8b 100644
--- a/libavcodec/h264_slice.c
+++ b/libavcodec/h264_slice.c
@@ -516,7 +516,10 @@ static int h264_frame_start(H264Context *h)
     pic->f->crop_top    = h->crop_top;
     pic->f->crop_bottom = h->crop_bottom;
 
-    pic->needs_fg = h->sei.common.film_grain_characteristics.present && !h->avctx->hwaccel &&
+    pic->needs_fg =
+        h->sei.common.film_grain_characteristics &&
+        h->sei.common.film_grain_characteristics->present &&
+        !h->avctx->hwaccel &&
         !(h->avctx->export_side_data & AV_CODEC_EXPORT_DATA_FILM_GRAIN);
 
     if ((ret = alloc_picture(h, pic)) < 0)
diff --git a/libavcodec/h264dec.c b/libavcodec/h264dec.c
index 0154fe17b6..af0913ca2c 100644
--- a/libavcodec/h264dec.c
+++ b/libavcodec/h264dec.c
@@ -156,6 +156,8 @@ void ff_h264_free_tables(H264Context *h)
     av_freep(&h->mb2b_xy);
     av_freep(&h->mb2br_xy);
 
+    av_freep(&h->h274db);
+
     ff_refstruct_pool_uninit(&h->qscale_table_pool);
     ff_refstruct_pool_uninit(&h->mb_type_pool);
     ff_refstruct_pool_uninit(&h->motion_val_pool);
diff --git a/libavcodec/h264dec.h b/libavcodec/h264dec.h
index ccd7583bf4..bbc2a185eb 100644
--- a/libavcodec/h264dec.h
+++ b/libavcodec/h264dec.h
@@ -344,7 +344,7 @@ typedef struct H264Context {
     H264DSPContext h264dsp;
     H264ChromaContext h264chroma;
     H264QpelContext h264qpel;
-    H274FilmGrainDatabase h274db;
+    H274FilmGrainDatabase* h274db;  // Dyanmic allocation due to large size.
 
     H264Picture DPB[H264_MAX_PICTURE_COUNT];
     H264Picture *cur_pic_ptr;
diff --git a/libavcodec/hevc/hevcdec.c b/libavcodec/hevc/hevcdec.c
index 4e3fa39e49..1ea8df0fa0 100644
--- a/libavcodec/hevc/hevcdec.c
+++ b/libavcodec/hevc/hevcdec.c
@@ -412,8 +412,8 @@ static int export_stream_params_from_sei(HEVCContext *s)
         avctx->color_trc = s->sei.common.alternative_transfer.preferred_transfer_characteristics;
     }
 
-    if (s->sei.common.film_grain_characteristics.present ||
-        s->sei.common.aom_film_grain.enable)
+    if ((s->sei.common.film_grain_characteristics && s->sei.common.film_grain_characteristics->present) ||
+        (s->sei.common.aom_film_grain && s->sei.common.aom_film_grain->enable))
         avctx->properties |= FF_CODEC_PROPERTY_FILM_GRAIN;
 
     return 0;
@@ -3267,8 +3267,8 @@ static int hevc_frame_start(HEVCContext *s, HEVCLayerContext *l,
     else
         s->cur_frame->f->flags &= ~AV_FRAME_FLAG_KEY;
 
-    s->cur_frame->needs_fg = (s->sei.common.film_grain_characteristics.present ||
-                              s->sei.common.aom_film_grain.enable) &&
+    s->cur_frame->needs_fg = ((s->sei.common.film_grain_characteristics && s->sei.common.film_grain_characteristics->present) ||
+                              (s->sei.common.aom_film_grain && s->sei.common.aom_film_grain->enable)) &&
         !(s->avctx->export_side_data & AV_CODEC_EXPORT_DATA_FILM_GRAIN) &&
         !s->avctx->hwaccel;
 
@@ -3277,8 +3277,8 @@ static int hevc_frame_start(HEVCContext *s, HEVCLayerContext *l,
         goto fail;
 
     if (s->cur_frame->needs_fg &&
-        (s->sei.common.film_grain_characteristics.present &&
-         !ff_h274_film_grain_params_supported(s->sei.common.film_grain_characteristics.model_id,
+        (s->sei.common.film_grain_characteristics && s->sei.common.film_grain_characteristics->present &&
+         !ff_h274_film_grain_params_supported(s->sei.common.film_grain_characteristics->model_id,
                                               s->cur_frame->f->format) ||
          !av_film_grain_params_select(s->cur_frame->f))) {
         av_log_once(s->avctx, AV_LOG_WARNING, AV_LOG_DEBUG, &s->film_grain_warning_shown,
@@ -3415,8 +3415,13 @@ static int hevc_frame_end(HEVCContext *s, HEVCLayerContext *l)
             av_assert0(0);
             return AVERROR_BUG;
         case AV_FILM_GRAIN_PARAMS_H274:
+            if (!s->h274db) {
+                s->h274db = av_mallocz(sizeof(*s->h274db));
+                if (!s->h274db)
+                    return AVERROR(ENOMEM);
+            }
             ret = ff_h274_apply_film_grain(out->frame_grain, out->f,
-                                           &s->h274db, fgp);
+                                           s->h274db, fgp);
             break;
         case AV_FILM_GRAIN_PARAMS_AV1:
             ret = ff_aom_apply_film_grain(out->frame_grain, out->f, fgp);
@@ -3844,6 +3849,7 @@ static av_cold int hevc_decode_free(AVCodecContext *avctx)
     av_buffer_unref(&s->rpu_buf);
 
     av_freep(&s->md5_ctx);
+    av_freep(&s->h274db);
 
     ff_container_fifo_free(&s->output_fifo);
 
diff --git a/libavcodec/hevc/hevcdec.h b/libavcodec/hevc/hevcdec.h
index 473709b4e8..73b792c880 100644
--- a/libavcodec/hevc/hevcdec.h
+++ b/libavcodec/hevc/hevcdec.h
@@ -531,7 +531,7 @@ typedef struct HEVCContext {
     HEVCDSPContext hevcdsp;
     VideoDSPContext vdsp;
     BswapDSPContext bdsp;
-    H274FilmGrainDatabase h274db;
+    H274FilmGrainDatabase* h274db;  // Dynamically allocated due to large size.
 
     /** used on BE to byteswap the lines for checksumming */
     uint8_t *checksum_buf;