[FFmpeg-cvslog] avformat/avidec: Avoid integer overflow in NI switch check

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Sat Feb 15 23:18:25 2020 +0100| [347920ca2102d762e4713f101a2e75811791e2b3] | committer: Michael Niedermayer

avformat/avidec: Avoid integer overflow in NI switch check

Fixes: signed integer overflow: 0 - -9223372036854775808 cannot be represented in type 'long'
Fixes: Ticket8149

Found-by: Suhwan
Reviewed-by: Paul B Mahol <onemda at gmail.com>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=347920ca2102d762e4713f101a2e75811791e2b3
---

 libavformat/avidec.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/libavformat/avidec.c b/libavformat/avidec.c
index ae0c227bb9..412e4a8479 100644
--- a/libavformat/avidec.c
+++ b/libavformat/avidec.c
@@ -1532,11 +1532,12 @@ resync:
         if (!avi->non_interleaved && st->nb_index_entries>1 && avi->index_loaded>1) {
             int64_t dts= av_rescale_q(pkt->dts, st->time_base, AV_TIME_BASE_Q);
 
-            if (avi->dts_max - dts > 2*AV_TIME_BASE) {
+            if (avi->dts_max < dts) {
+                avi->dts_max = dts;
+            } else if (avi->dts_max - (uint64_t)dts > 2*AV_TIME_BASE) {
                 avi->non_interleaved= 1;
                 av_log(s, AV_LOG_INFO, "Switching to NI mode, due to poor interleaving\n");
-            }else if (avi->dts_max < dts)
-                avi->dts_max = dts;
+            }
         }
 
         return 0;