diff --git a/libavcodec/h264_slice.c b/libavcodec/h264_slice.c
index 90e05ed8f1..b381397b4d 100644
--- a/libavcodec/h264_slice.c
+++ b/libavcodec/h264_slice.c
@@ -2762,7 +2762,7 @@ int ff_h264_execute_decode_slices(H264Context *h)
 
             sl                 = &h->slice_ctx[i];
             if (CONFIG_ERROR_RESILIENCE) {
-                sl->er.error_count = 0;
+                sl->er.error_count = ATOMIC_VAR_INIT(0);
             }
 
             /* make sure none of those slices overlap */
@@ -2786,7 +2786,8 @@ int ff_h264_execute_decode_slices(H264Context *h)
         h->mb_y              = sl->mb_y;
         if (CONFIG_ERROR_RESILIENCE) {
             for (i = 1; i < context_count; i++)
-                h->slice_ctx[0].er.error_count += h->slice_ctx[i].er.error_count;
+                atomic_fetch_add(&h->slice_ctx[0].er.error_count,
+                                 atomic_load(&h->slice_ctx[i].er.error_count));
         }
 
         if (h->postpone_filter) {
diff --git a/libavcodec/mpeg12dec.c b/libavcodec/mpeg12dec.c
index 9e076e89da..ad2586dc07 100644
--- a/libavcodec/mpeg12dec.c
+++ b/libavcodec/mpeg12dec.c
@@ -1992,7 +1992,8 @@ static int slice_decode_thread(AVCodecContext *c, void *arg)
     int mb_y            = s->start_mb_y;
     const int field_pic = s->picture_structure != PICT_FRAME;
 
-    s->er.error_count = (3 * (s->end_mb_y - s->start_mb_y) * s->mb_width) >> field_pic;
+    s->er.error_count = ATOMIC_VAR_INIT(
+        (3 * (s->end_mb_y - s->start_mb_y) * s->mb_width) >> field_pic);
 
     for (;;) {
         uint32_t start_code;
@@ -2002,7 +2003,7 @@ static int slice_decode_thread(AVCodecContext *c, void *arg)
         emms_c();
         ff_dlog(c, "ret:%d resync:%d/%d mb:%d/%d ts:%d/%d ec:%d\n",
                 ret, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y,
-                s->start_mb_y, s->end_mb_y, s->er.error_count);
+                s->start_mb_y, s->end_mb_y, atomic_load(&s->er.error_count));
         if (ret < 0) {
             if (c->err_recognition & AV_EF_EXPLODE)
                 return ret;
@@ -2485,7 +2486,8 @@ static int decode_chunks(AVCodecContext *avctx, AVFrame *picture,
                                    &s2->thread_context[0], NULL,
                                    s->slice_count, sizeof(void *));
                     for (i = 0; i < s->slice_count; i++)
-                        s2->er.error_count += s2->thread_context[i]->er.error_count;
+                        atomic_fetch_add(&s2->er.error_count,
+                            atomic_load(&s2->thread_context[i]->er.error_count));
                 }
 
                 ret = slice_end(avctx, picture);
@@ -2499,7 +2501,8 @@ static int decode_chunks(AVCodecContext *avctx, AVFrame *picture,
             }
             s2->pict_type = 0;
 
-            if (avctx->err_recognition & AV_EF_EXPLODE && s2->er.error_count)
+            if (avctx->err_recognition & AV_EF_EXPLODE &&
+                atomic_load(&s2->er.error_count))
                 return AVERROR_INVALIDDATA;
 
             return FFMAX(0, buf_ptr - buf - s2->parse_context.last_index);
@@ -2553,7 +2556,8 @@ static int decode_chunks(AVCodecContext *avctx, AVFrame *picture,
                                s2->thread_context, NULL,
                                s->slice_count, sizeof(void *));
                 for (i = 0; i < s->slice_count; i++)
-                    s2->er.error_count += s2->thread_context[i]->er.error_count;
+                    atomic_fetch_add(&s2->er.error_count,
+                        atomic_load(&s2->thread_context[i]->er.error_count));
                 s->slice_count = 0;
             }
             if (last_code == 0 || last_code == SLICE_MIN_START_CODE) {
diff --git a/libavcodec/mpegvideo_enc.c b/libavcodec/mpegvideo_enc.c
index 979e138b88..b69e0e1727 100644
--- a/libavcodec/mpegvideo_enc.c
+++ b/libavcodec/mpegvideo_enc.c
@@ -3595,7 +3595,8 @@ static void merge_context_after_encode(MpegEncContext *dst, MpegEncContext *src)
     MERGE(b_count);
     MERGE(skip_count);
     MERGE(misc_bits);
-    MERGE(er.error_count);
+    atomic_fetch_add(&dst->er.error_count, atomic_load(&src->er.error_count));
+    src->er.error_count = ATOMIC_VAR_INIT(0);
     MERGE(padding_bug_score);
     MERGE(current_picture.encoding_error[0]);
     MERGE(current_picture.encoding_error[1]);
