diff --git a/libavcodec/dnxhdenc.c b/libavcodec/dnxhdenc.c
index 86e71ca8b034d..01e22e7764f3b 100644
--- a/libavcodec/dnxhdenc.c
+++ b/libavcodec/dnxhdenc.c
@@ -1369,8 +1369,10 @@ static av_cold int dnxhd_encode_end(AVCodecContext *avctx)
     av_freep(&ctx->qmatrix_c16);
     av_freep(&ctx->qmatrix_l16);
 
-    for (i = 1; i < avctx->thread_count; i++)
-        av_freep(&ctx->thread[i]);
+    if (avctx->active_thread_type == FF_THREAD_SLICE) {
+        for (i = 1; i < avctx->thread_count; i++)
+            av_freep(&ctx->thread[i]);
+    }
 
     return 0;
 }