[FFmpeg-cvslog] avcodec/h264_slice: Dont reset mb_aff_frame per slice

[Michael Niedermayer]

ffmpeg | branch: release/2.2 | Michael Niedermayer <michaelni at gmx.at> | Wed Apr  8 12:29:47 2015 +0200| [0df90898f5a3cbbb8c664a05d69c29655ccf0a80] | committer: Michael Niedermayer

avcodec/h264_slice: Dont reset mb_aff_frame per slice

Fixes null pointer dereference
Fixes Ticket4440

Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
(cherry picked from commit 386601286fed2dff5e1955bc21a0256f6f35ab19)

Conflicts:

	libavcodec/h264_slice.c
(cherry picked from commit ce6d38e9ed0842870f3cd5414937bb6d1f2417d9)

Conflicts:

	libavcodec/h264_slice.c

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=0df90898f5a3cbbb8c664a05d69c29655ccf0a80
---

 libavcodec/h264.c |   10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/libavcodec/h264.c b/libavcodec/h264.c
index 61fd02f..f17304e 100644
--- a/libavcodec/h264.c
+++ b/libavcodec/h264.c
@@ -3512,6 +3512,7 @@ static int decode_slice_header(H264Context *h, H264Context *h0)
     int field_pic_flag, bottom_field_flag;
     int first_slice = h == h0 && !h0->current_slice;
     int frame_num, picture_structure, droppable;
+    int mb_aff_frame, last_mb_aff_frame;
     PPS *pps;
 
     h->me.qpel_put = h->h264qpel.put_h264_qpel_pixels_tab;
@@ -3727,7 +3728,8 @@ static int decode_slice_header(H264Context *h, H264Context *h0)
     }
 
     h->mb_mbaff        = 0;
-    h->mb_aff_frame    = 0;
+    mb_aff_frame       = 0;
+    last_mb_aff_frame  = h0->mb_aff_frame;
     last_pic_structure = h0->picture_structure;
     last_pic_droppable = h0->droppable;
     droppable          = h->nal_ref_idc == 0;
@@ -3745,12 +3747,13 @@ static int decode_slice_header(H264Context *h, H264Context *h0)
             picture_structure = PICT_TOP_FIELD + bottom_field_flag;
         } else {
             picture_structure = PICT_FRAME;
-            h->mb_aff_frame      = h->sps.mb_aff;
+            mb_aff_frame      = h->sps.mb_aff;
         }
     }
     if (h0->current_slice) {
         if (last_pic_structure != picture_structure ||
-            last_pic_droppable != droppable) {
+            last_pic_droppable != droppable ||
+            last_mb_aff_frame  != mb_aff_frame) {
             av_log(h->avctx, AV_LOG_ERROR,
                    "Changing field mode (%d -> %d) between slices is not allowed\n",
                    last_pic_structure, h->picture_structure);
@@ -3766,6 +3769,7 @@ static int decode_slice_header(H264Context *h, H264Context *h0)
     h->picture_structure = picture_structure;
     h->droppable         = droppable;
     h->frame_num         = frame_num;
+    h->mb_aff_frame      = mb_aff_frame;
     h->mb_field_decoding_flag = picture_structure != PICT_FRAME;
 
     if (h0->current_slice == 0) {