lavf: make av_set_pts_info private.

It's supposed to be called only from (de)muxers.

libavformat/ncdec.c

@@ -22,6 +22,7 @@
 
 #include "libavutil/intreadwrite.h"
 #include "avformat.h"
+#include "internal.h"
 
 #define NC_VIDEO_FLAG 0x1A5
 
@@ -54,7 +55,7 @@ static int nc_read_header(AVFormatContext *s, AVFormatParameters *ap)
     st->codec->codec_id   = CODEC_ID_MPEG4;
     st->need_parsing      = AVSTREAM_PARSE_FULL;
 
-    av_set_pts_info(st, 64, 1, 100);
+    avpriv_set_pts_info(st, 64, 1, 100);
 
     return 0;
 }