[FFmpeg-cvslog] avformat/rtpenc: Fix integer overflow in NTP_TO_RTP_FORMAT

[Boris Nagels]

ffmpeg | branch: master | Boris Nagels <develop at focusware.nl> | Sun Mar  6 16:31:36 2016 +0100| [1109ed7973c7fd1e7001898adc4976590d862122] | committer: Michael Niedermayer

avformat/rtpenc: Fix integer overflow in NTP_TO_RTP_FORMAT

RTCP synchronization packet was broken since commit in ffmpeg version > 2.8.3
(commit: e04b039b1528f4c7df5c2b93865651bfea168a19) Since this commit (2e814d0329aded98c811d0502839618f08642685)
"rtpenc: Simplify code by introducing a macro for rescaling NTP timestamps", NTP_TO_RTP_FORMAT
uses av_rescale_rnd() function to add the data to the packet.

This causes an overflow in the av_rescale_rnd() function and it will return INT64_MIN.
Causing the NTP stamp in the RTCP packet to have an invalid value.

Github: Closes #182

Reverting commit '2e814d0329aded98c811d0502839618f08642685' solves the problem.

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=1109ed7973c7fd1e7001898adc4976590d862122
---

 libavformat/rtpenc.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libavformat/rtpenc.c b/libavformat/rtpenc.c
index 31569d6..00b69f5 100644
--- a/libavformat/rtpenc.c
+++ b/libavformat/rtpenc.c
@@ -271,7 +271,8 @@ static void rtcp_send_sr(AVFormatContext *s1, int64_t ntp_time, int bye)
     avio_w8(s1->pb, RTCP_SR);
     avio_wb16(s1->pb, 6); /* length in words - 1 */
     avio_wb32(s1->pb, s->ssrc);
-    avio_wb64(s1->pb, NTP_TO_RTP_FORMAT(ntp_time));
+    avio_wb32(s1->pb, ntp_time / 1000000);
+    avio_wb32(s1->pb, ((ntp_time % 1000000) << 32) / 1000000);
     avio_wb32(s1->pb, rtp_ts);
     avio_wb32(s1->pb, s->packet_count);
     avio_wb32(s1->pb, s->octet_count);