diff --git a/libavformat/avidec.c b/libavformat/avidec.c
index f48c441ad3..a2c230cd7c 100644
--- a/libavformat/avidec.c
+++ b/libavformat/avidec.c
@@ -1525,6 +1525,7 @@ AVInputFormat ff_avi_demuxer = {
     .name           = "avi",
     .long_name      = NULL_IF_CONFIG_SMALL("AVI (Audio Video Interleaved)"),
     .priv_data_size = sizeof(AVIContext),
+    .extensions     = "avi",
     .read_probe     = avi_probe,
     .read_header    = avi_read_header,
     .read_packet    = avi_read_packet,
diff --git a/libavformat/mov.c b/libavformat/mov.c
index afd3fc6638..2900b1edc0 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -3137,6 +3137,7 @@ AVInputFormat ff_mov_demuxer = {
     .name           = "mov,mp4,m4a,3gp,3g2,mj2",
     .long_name      = NULL_IF_CONFIG_SMALL("QuickTime / MOV"),
     .priv_data_size = sizeof(MOVContext),
+    .extensions     = "mov,mp4,m4a,3gp,3g2,mj2",
     .read_probe     = mov_probe,
     .read_header    = mov_read_header,
     .read_packet    = mov_read_packet,