diff --git a/libavformat/hashenc.c b/libavformat/hashenc.c
index ddc67f53b5..ce609f6efa 100644
--- a/libavformat/hashenc.c
+++ b/libavformat/hashenc.c
@@ -324,7 +324,6 @@ static int framehash_write_packet(struct AVFormatContext *s, AVPacket *pkt)
     }
 
     avio_printf(s->pb, "\n");
-    avio_flush(s->pb);
     return 0;
 }
 
diff --git a/libavformat/img2enc.c b/libavformat/img2enc.c
index 39398f37a3..5ee99890ce 100644
--- a/libavformat/img2enc.c
+++ b/libavformat/img2enc.c
@@ -118,7 +118,6 @@ static int write_packet_pipe(AVFormatContext *s, AVPacket *pkt)
             return ret;
     } else {
         avio_write(s->pb, pkt->data, pkt->size);
-        avio_flush(s->pb);
     }
     img->img_number++;
     return 0;
diff --git a/libavformat/mxfenc.c b/libavformat/mxfenc.c
index e187b3845d..396768d51f 100644
--- a/libavformat/mxfenc.c
+++ b/libavformat/mxfenc.c
@@ -2799,7 +2799,6 @@ static int mxf_write_opatom_packet(AVFormatContext *s, AVPacket *pkt, MXFIndexEn
     mxf->edit_units_count++;
     avio_write(pb, pkt->data, pkt->size);
     mxf->body_offset += pkt->size;
-    avio_flush(pb);
 
     return 0;
 }
@@ -2937,8 +2936,6 @@ static int mxf_write_packet(AVFormatContext *s, AVPacket *pkt)
         mxf->body_offset += 16+4+pkt->size + klv_fill_size(16+4+pkt->size);
     }
 
-    avio_flush(pb);
-
     return 0;
 }