[FFmpeg-cvslog] ituh263dec: Implement enough of Annex O (scalability) to fix a FPE.

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michaelni at gmx.at> | Thu Mar 29 16:54:28 2012 -0700| [1f05dcbad243622020151a3b0b45c68ea5f2866c] | committer: Ronald S. Bultje

ituh263dec: Implement enough of Annex O (scalability) to fix a FPE.

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Ronald S. Bultje <rsbultje at gmail.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=1f05dcbad243622020151a3b0b45c68ea5f2866c
---

 libavcodec/ituh263dec.c |   16 ++++++++++++++++
 1 files changed, 16 insertions(+), 0 deletions(-)

diff --git a/libavcodec/ituh263dec.c b/libavcodec/ituh263dec.c
index f52ac7a..73e8bf5 100644
--- a/libavcodec/ituh263dec.c
+++ b/libavcodec/ituh263dec.c
@@ -1083,6 +1083,22 @@ int ff_h263_decode_picture_header(MpegEncContext *s)
         skip_bits(&s->gb, 2); /* Quantization information for B-pictures */
     }
 
+    if (s->pict_type!=AV_PICTURE_TYPE_B) {
+        s->time            = s->picture_number;
+        s->pp_time         = s->time - s->last_non_b_time;
+        s->last_non_b_time = s->time;
+    }else{
+        s->time    = s->picture_number;
+        s->pb_time = s->pp_time - (s->last_non_b_time - s->time);
+        if (s->pp_time <=s->pb_time ||
+            s->pp_time <= s->pp_time - s->pb_time ||
+            s->pp_time <= 0){
+            s->pp_time = 2;
+            s->pb_time = 1;
+        }
+        ff_mpeg4_init_direct_mv(s);
+    }
+
     /* PEI */
     while (get_bits1(&s->gb) != 0) {
         skip_bits(&s->gb, 8);