diff --git a/libavformat/avisynth.c b/libavformat/avisynth.c
index 3b695a9..893ce3f 100644
--- a/libavformat/avisynth.c
+++ b/libavformat/avisynth.c
@@ -49,10 +49,15 @@ static int avisynth_read_header(AVFormatContext *s)
   DWORD id;
   AVStream *st;
   AVISynthStream *stream;
+  wchar_t filename_wchar[1024] = { 0 };
+  char filename_char[1024] = { 0 };

   AVIFileInit();

-  res = AVIFileOpen(&avs->file, s->filename, OF_READ|OF_SHARE_DENY_WRITE, NULL);
+  MultiByteToWideChar(CP_UTF8, 0, s->filename, -1, filename_wchar, 1024);
+  WideCharToMultiByte(CP_OEMCP, 0, filename_wchar, -1, filename_char, 1024, NULL, NULL);
+
+  res = AVIFileOpen(&avs->file, filename_char, OF_READ|OF_SHARE_DENY_WRITE, NULL);
   if (res != S_OK)
     {
       av_log(s, AV_LOG_ERROR, "AVIFileOpen failed with error %ld", res);