diff --git a/libavcodec/hevc_ps.c b/libavcodec/hevc_ps.c
index 6475d86d7d..7f74553fc1 100644
--- a/libavcodec/hevc_ps.c
+++ b/libavcodec/hevc_ps.c
@@ -442,47 +442,42 @@ static int decode_hrd(GetBitContext *gb, int common_inf_present,
     return 0;
 }
 
-static void uninit_vps(FFRefStructOpaque opaque, void *obj)
+static void hevc_vps_free(FFRefStructOpaque opaque, void *obj)
 {
     HEVCVPS *vps = obj;
 
     av_freep(&vps->hdr);
-}
-
-static int compare_vps(const HEVCVPS *vps1, const HEVCVPS *vps2)
-{
-    if (!memcmp(vps1, vps2, offsetof(HEVCVPS, hdr)))
-        return !vps1->vps_num_hrd_parameters ||
-               !memcmp(vps1->hdr, vps2->hdr, vps1->vps_num_hrd_parameters * sizeof(*vps1->hdr));
-
-    return 0;
+    av_freep(&vps->data);
 }
 
 int ff_hevc_decode_nal_vps(GetBitContext *gb, AVCodecContext *avctx,
                            HEVCParamSets *ps)
 {
     int i,j;
-    int vps_id = 0;
-    ptrdiff_t nal_size;
-    HEVCVPS *vps = ff_refstruct_alloc_ext(sizeof(*vps), 0, NULL, uninit_vps);
+    int vps_id = get_bits(gb, 4);
+    int ret = AVERROR_INVALIDDATA;
+    HEVCVPS *vps;
 
+    if (ps->pps_list[vps_id]) {
+        const HEVCVPS *vps1 = ps->vps_list[vps_id];
+        if (vps1->data_size == gb->buffer_end - gb->buffer &&
+            !memcmp(vps1->data, gb->buffer, vps1->data_size))
+            return 0;
+    }
+
+    vps = ff_refstruct_alloc_ext(sizeof(*vps), 0, NULL, hevc_vps_free);
     if (!vps)
         return AVERROR(ENOMEM);
 
     av_log(avctx, AV_LOG_DEBUG, "Decoding VPS\n");
 
-    nal_size = gb->buffer_end - gb->buffer;
-    if (nal_size > sizeof(vps->data)) {
-        av_log(avctx, AV_LOG_WARNING, "Truncating likely oversized VPS "
-               "(%"PTRDIFF_SPECIFIER" > %"SIZE_SPECIFIER")\n",
-               nal_size, sizeof(vps->data));
-        vps->data_size = sizeof(vps->data);
-    } else {
-        vps->data_size = nal_size;
+    vps->data_size = gb->buffer_end - gb->buffer;
+    vps->data = av_memdup(gb->buffer, vps->data_size);
+    if (!vps->data) {
+        ret = AVERROR(ENOMEM);
+        goto err;
     }
-    memcpy(vps->data, gb->buffer, vps->data_size);
-
-    vps_id = vps->vps_id = get_bits(gb, 4);
+    vps->vps_id = vps_id;
 
     if (get_bits(gb, 2) != 3) { // vps_reserved_three_2bits
         av_log(avctx, AV_LOG_ERROR, "vps_reserved_three_2bits is not three\n");
@@ -579,19 +574,14 @@ int ff_hevc_decode_nal_vps(GetBitContext *gb, AVCodecContext *avctx,
             goto err;
     }
 
-    if (ps->vps_list[vps_id] &&
-        compare_vps(ps->vps_list[vps_id], vps)) {
-        ff_refstruct_unref(&vps);
-    } else {
         remove_vps(ps, vps_id);
         ps->vps_list[vps_id] = vps;
-    }
 
     return 0;
 
 err:
     ff_refstruct_unref(&vps);
-    return AVERROR_INVALIDDATA;
+    return ret;
 }
 
 static void decode_vui(GetBitContext *gb, AVCodecContext *avctx,
@@ -1294,36 +1284,43 @@ int ff_hevc_parse_sps(HEVCSPS *sps, GetBitContext *gb, unsigned int *sps_id,
     return 0;
 }
 
+static void hevc_sps_free(FFRefStructOpaque opaque, void *obj)
+{
+    HEVCSPS *sps = obj;
+
+    av_freep(&sps->data);
+}
+
+static int compare_sps(const HEVCSPS *sps1, const HEVCSPS *sps2)
+{
+    return sps1->data_size == sps2->data_size &&
+           !memcmp(sps1->data, sps2->data, sps1->data_size);
+}
+
 int ff_hevc_decode_nal_sps(GetBitContext *gb, AVCodecContext *avctx,
                            HEVCParamSets *ps, int apply_defdispwin)
 {
-    HEVCSPS *sps = ff_refstruct_allocz(sizeof(*sps));
+    HEVCSPS *sps = ff_refstruct_alloc_ext(sizeof(*sps), 0, NULL, hevc_sps_free);
     unsigned int sps_id;
     int ret;
-    ptrdiff_t nal_size;
 
     if (!sps)
         return AVERROR(ENOMEM);
 
     av_log(avctx, AV_LOG_DEBUG, "Decoding SPS\n");
 
-    nal_size = gb->buffer_end - gb->buffer;
-    if (nal_size > sizeof(sps->data)) {
-        av_log(avctx, AV_LOG_WARNING, "Truncating likely oversized SPS "
-               "(%"PTRDIFF_SPECIFIER" > %"SIZE_SPECIFIER")\n",
-               nal_size, sizeof(sps->data));
-        sps->data_size = sizeof(sps->data);
-    } else {
-        sps->data_size = nal_size;
+    sps->data_size = gb->buffer_end - gb->buffer;
+    sps->data = av_memdup(gb->buffer, sps->data_size);
+    if (!sps->data) {
+        ret = AVERROR(ENOMEM);
+        goto err;
     }
-    memcpy(sps->data, gb->buffer, sps->data_size);
 
     ret = ff_hevc_parse_sps(sps, gb, &sps_id,
                             apply_defdispwin,
                             ps->vps_list, avctx);
     if (ret < 0) {
-        ff_refstruct_unref(&sps);
-        return ret;
+        goto err;
     }
 
     if (avctx->debug & FF_DEBUG_BITSTREAM) {
@@ -1340,7 +1337,7 @@ int ff_hevc_decode_nal_sps(GetBitContext *gb, AVCodecContext *avctx,
      * original one.
      * otherwise drop all PPSes that depend on it */
     if (ps->sps_list[sps_id] &&
-        !memcmp(ps->sps_list[sps_id], sps, sizeof(*sps))) {
+        compare_sps(ps->sps_list[sps_id], sps)) {
         ff_refstruct_unref(&sps);
     } else {
         remove_sps(ps, sps_id);
@@ -1348,6 +1345,9 @@ int ff_hevc_decode_nal_sps(GetBitContext *gb, AVCodecContext *avctx,
     }
 
     return 0;
+err:
+    ff_refstruct_unref(&sps);
+    return ret;
 }
 
 static void hevc_pps_free(FFRefStructOpaque unused, void *obj)
@@ -1364,6 +1364,7 @@ static void hevc_pps_free(FFRefStructOpaque unused, void *obj)
     av_freep(&pps->tile_pos_rs);
     av_freep(&pps->tile_id);
     av_freep(&pps->min_tb_addr_zs_tab);
+    av_freep(&pps->data);
 }
 
 static void colour_mapping_octants(GetBitContext *gb, HEVCPPS *pps, int inp_depth,
@@ -1762,27 +1763,35 @@ int ff_hevc_decode_nal_pps(GetBitContext *gb, AVCodecContext *avctx,
     const HEVCSPS *sps = NULL;
     const HEVCVPS *vps = NULL;
     int i, ret = 0;
-    unsigned int pps_id = 0;
-    ptrdiff_t nal_size;
+    unsigned int pps_id = get_ue_golomb_long(gb);
     unsigned log2_parallel_merge_level_minus2;
+    HEVCPPS *pps;
+
+    av_log(avctx, AV_LOG_DEBUG, "Decoding PPS\n");
+
+    if (pps_id >= HEVC_MAX_PPS_COUNT) {
+        av_log(avctx, AV_LOG_ERROR, "PPS id out of range: %d\n", pps_id);
+        ret = AVERROR_INVALIDDATA;
+        goto err;
+    }
 
-    HEVCPPS *pps = ff_refstruct_alloc_ext(sizeof(*pps), 0, NULL, hevc_pps_free);
+    if (ps->pps_list[pps_id]) {
+        const HEVCPPS *pps1 = ps->pps_list[pps_id];
+        if (pps1->data_size == gb->buffer_end - gb->buffer &&
+            !memcmp(pps1->data, gb->buffer, pps1->data_size))
+            return 0;
+    }
 
+    pps = ff_refstruct_alloc_ext(sizeof(*pps), 0, NULL, hevc_pps_free);
     if (!pps)
         return AVERROR(ENOMEM);
 
-    av_log(avctx, AV_LOG_DEBUG, "Decoding PPS\n");
-
-    nal_size = gb->buffer_end - gb->buffer;
-    if (nal_size > sizeof(pps->data)) {
-        av_log(avctx, AV_LOG_WARNING, "Truncating likely oversized PPS "
-               "(%"PTRDIFF_SPECIFIER" > %"SIZE_SPECIFIER")\n",
-               nal_size, sizeof(pps->data));
-        pps->data_size = sizeof(pps->data);
-    } else {
-        pps->data_size = nal_size;
+    pps->data_size = gb->buffer_end - gb->buffer;
+    pps->data = av_memdup(gb->buffer, pps->data_size);
+    if (!pps->data) {
+        ret = AVERROR_INVALIDDATA;
+        goto err;
     }
-    memcpy(pps->data, gb->buffer, pps->data_size);
 
     // Default values
     pps->loop_filter_across_tiles_enabled_flag = 1;
@@ -1795,7 +1804,7 @@ int ff_hevc_decode_nal_pps(GetBitContext *gb, AVCodecContext *avctx,
     pps->log2_max_transform_skip_block_size    = 2;
 
     // Coded parameters
-    pps_id = pps->pps_id = get_ue_golomb_long(gb);
+    pps->pps_id = pps_id;
     if (pps_id >= HEVC_MAX_PPS_COUNT) {
         av_log(avctx, AV_LOG_ERROR, "PPS id out of range: %d\n", pps_id);
         ret = AVERROR_INVALIDDATA;
diff --git a/libavcodec/hevc_ps.h b/libavcodec/hevc_ps.h
index 0d8eaf2b3e..bed406770f 100644
--- a/libavcodec/hevc_ps.h
+++ b/libavcodec/hevc_ps.h
@@ -172,11 +172,11 @@ typedef struct HEVCVPS {
     int vps_num_ticks_poc_diff_one; ///< vps_num_ticks_poc_diff_one_minus1 + 1
     int vps_num_hrd_parameters;
 
-    uint8_t data[4096];
-    int data_size;
-    /* Put this at the end of the structure to make it easier to calculate the
+    /* Keep this at the end of the structure to make it easier to calculate the
      * size before this pointer, which is used for memcmp */
     HEVCHdrParams *hdr;
+    uint8_t *data;
+    int data_size;
 } HEVCVPS;
 
 typedef struct ScalingList {
@@ -299,7 +299,9 @@ typedef struct HEVCSPS {
 
     int qp_bd_offset;
 
-    uint8_t data[4096];
+    /* Keep this at the end of the structure to make it easier to calculate the
+     * size before this pointer, which is used for memcmp */
+    uint8_t *data;
     int data_size;
 } HEVCSPS;
 
@@ -434,7 +436,9 @@ typedef struct HEVCPPS {
     int *min_tb_addr_zs;    ///< MinTbAddrZS
     int *min_tb_addr_zs_tab;///< MinTbAddrZS
 
-    uint8_t data[4096];
+    /* Keep this at the end of the structure to make it easier to calculate the
+     * size before this pointer, which is used for memcmp */
+    uint8_t *data;
     int data_size;
 } HEVCPPS;
 
