diff --git a/libavformat/Makefile b/libavformat/Makefile
index f348559399..479361aed9 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -84,7 +84,7 @@ OBJS-$(CONFIG_APNG_MUXER)                += apngenc.o
 OBJS-$(CONFIG_AQTITLE_DEMUXER)           += aqtitledec.o subtitles.o
 OBJS-$(CONFIG_ASF_DEMUXER)               += asfdec_f.o asf.o asfcrypt.o \
                                             avlanguage.o
-OBJS-$(CONFIG_ASF_O_DEMUXER)             += asfdec-o.o asf.o asfcrypt.o \
+OBJS-$(CONFIG_ASF_O_DEMUXER)             += asfdec_o.o asf.o asfcrypt.o \
                                             avlanguage.o
 OBJS-$(CONFIG_ASF_MUXER)                 += asfenc.o asf.o
 OBJS-$(CONFIG_ASS_DEMUXER)               += assdec.o subtitles.o
diff --git a/libavformat/asfdec-o.c b/libavformat/asfdec_o.c
similarity index 100%
rename from libavformat/asfdec-o.c
rename to libavformat/asfdec_o.c