xmv: signal EOF

Fixes #1946.

Signed-off-by: Paul B Mahol <onemda@gmail.com>

libavformat/xmv.c

@@ -379,6 +379,9 @@ static int xmv_fetch_new_packet(AVFormatContext *s)
     AVIOContext     *pb  = s->pb;
     int result;
 
+    if (xmv->this_packet_offset == xmv->next_packet_offset)
+        return AVERROR_EOF;
+
     /* Seek to it */
     xmv->this_packet_offset = xmv->next_packet_offset;
     if (avio_seek(pb, xmv->this_packet_offset, SEEK_SET) != xmv->this_packet_offset)