enable rtp payload size AVOption for video encoding

Originally committed as revision 8163 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/utils.c

@@ -474,7 +474,7 @@ static const AVOption options[]={
 {"b_strategy", "strategy to choose between I/P/B-frames", OFFSET(b_frame_strategy), FF_OPT_TYPE_INT, 0, INT_MIN, INT_MAX, V|E},
 {"hurry_up", NULL, OFFSET(hurry_up), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX, V|D},
 {"rtp_mode", NULL, OFFSET(rtp_mode), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX},
-{"rtp_payload_size", NULL, OFFSET(rtp_payload_size), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX},
+{"rtp_payload_size", NULL, OFFSET(rtp_payload_size), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX, V|E},
 {"mv_bits", NULL, OFFSET(mv_bits), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX},
 {"header_bits", NULL, OFFSET(header_bits), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX},
 {"i_tex_bits", NULL, OFFSET(i_tex_bits), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX},