diff --git a/libavformat/mxfenc.c b/libavformat/mxfenc.c
index 841e727791..ea7a4bbf93 100644
--- a/libavformat/mxfenc.c
+++ b/libavformat/mxfenc.c
@@ -447,7 +447,7 @@ static void mxf_write_preface(AVFormatContext *s)
 
     mxf_write_metadata_key(pb, 0x012f00);
     PRINT_KEY(s, "preface key", pb->buf_ptr - 16);
-    klv_encode_ber_length(pb, 130 + 16 * mxf->essence_container_count);
+    klv_encode_ber_length(pb, 130 + 16LL * mxf->essence_container_count);
 
     // write preface set uid
     mxf_write_local_tag(pb, 16, 0x3C0A);
@@ -720,7 +720,7 @@ static void mxf_write_multi_descriptor(AVFormatContext *s)
 
     mxf_write_metadata_key(pb, 0x014400);
     PRINT_KEY(s, "multiple descriptor key", pb->buf_ptr - 16);
-    klv_encode_ber_length(pb, 64 + 16 * s->nb_streams);
+    klv_encode_ber_length(pb, 64 + 16LL * s->nb_streams);
 
     mxf_write_local_tag(pb, 16, 0x3C0A);
     mxf_write_uuid(pb, MultipleDescriptor, 0);
@@ -1053,8 +1053,8 @@ static void mxf_write_index_table_segment(AVFormatContext *s)
     if (mxf->edit_unit_byte_count) {
         klv_encode_ber_length(pb, 80);
     } else {
-        klv_encode_ber_length(pb, 85 + 12+(s->nb_streams+1)*6 +
-                              12+mxf->edit_units_count*(11+mxf->slice_count*4));
+        klv_encode_ber_length(pb, 85 + 12+(s->nb_streams+1LL)*6 +
+                              12+mxf->edit_units_count*(11+mxf->slice_count*4LL));
     }
 
     // instance id
@@ -1216,7 +1216,7 @@ static int mxf_write_partition(AVFormatContext *s, int bodysid,
 
     // write klv
     avio_write(pb, key, 16);
-    klv_encode_ber_length(pb, 88 + 16 * mxf->essence_container_count);
+    klv_encode_ber_length(pb, 88 + 16LL * mxf->essence_container_count);
 
     // write partition value
     avio_wb16(pb, 1); // majorVersion
@@ -1761,7 +1761,7 @@ static void mxf_write_random_index_pack(AVFormatContext *s)
     int i;
 
     avio_write(pb, random_index_pack_key, 16);
-    klv_encode_ber_length(pb, 28 + 12*mxf->body_partitions_count);
+    klv_encode_ber_length(pb, 28 + 12LL*mxf->body_partitions_count);
 
     if (mxf->edit_unit_byte_count)
         avio_wb32(pb, 1); // BodySID of header partition