[FFmpeg-cvslog] avcodec/mpeg4videodec: set field durations to safe values when they are invalid

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michaelni at gmx.at> | Wed Feb 19 05:54:54 2014 +0100| [36fb07d1abc7738427c98cfb154e2d1b9bcc40fe] | committer: Michael Niedermayer

avcodec/mpeg4videodec: set field durations to safe values when they are invalid

Fixes division by 0
Fixes: 3c980274cecaca6ca5d6e517c0c1983e-signal_sigabrt_7ffff7125425_410_cov_3621042467_2_audio_streams.avi
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=36fb07d1abc7738427c98cfb154e2d1b9bcc40fe
---

 libavcodec/mpeg4videodec.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/libavcodec/mpeg4videodec.c b/libavcodec/mpeg4videodec.c
index 1771e71..22e706e 100644
--- a/libavcodec/mpeg4videodec.c
+++ b/libavcodec/mpeg4videodec.c
@@ -2297,8 +2297,10 @@ static int decode_vop_header(Mpeg4DecContext *ctx, GetBitContext *gb)
                             ROUNDED_DIV(s->last_non_b_time - s->pp_time, ctx->t_frame)) * 2;
         s->pb_field_time = (ROUNDED_DIV(s->time, ctx->t_frame) -
                             ROUNDED_DIV(s->last_non_b_time - s->pp_time, ctx->t_frame)) * 2;
-        if (!s->progressive_sequence) {
-            if (s->pp_field_time <= s->pb_field_time || s->pb_field_time <= 1)
+        if (s->pp_field_time <= s->pb_field_time || s->pb_field_time <= 1) {
+            s->pb_field_time = 2;
+            s->pp_field_time = 4;
+            if (!s->progressive_sequence)
                 return FRAME_SKIPPED;
         }
     }