From 23daee0dcc57b647b9d62d4c905e94acf0c6b8e0 Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michaelni@gmx.at>
Date: Thu, 18 Apr 2013 19:53:00 +0200
Subject: [PATCH] avcodec/mpegvideo_motion: Check P field references
If a reference is unavailable use a field from the current
picture
Fixes null pointer dereference
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
---
libavcodec/mpegvideo_motion.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/libavcodec/mpegvideo_motion.c b/libavcodec/mpegvideo_motion.c
index be1b48d4d8a..225e9a637f5 100644
--- a/libavcodec/mpegvideo_motion.c
+++ b/libavcodec/mpegvideo_motion.c
@@ -809,7 +809,8 @@ static av_always_inline void MPV_motion_internal(MpegEncContext *s,
s->mv[dir][1][0], s->mv[dir][1][1], 8, mb_y);
}
} else {
- if(s->picture_structure != s->field_select[dir][0] + 1 && s->pict_type != AV_PICTURE_TYPE_B && !s->first_field){
+ if( s->picture_structure != s->field_select[dir][0] + 1 && s->pict_type != AV_PICTURE_TYPE_B && !s->first_field
+ || !ref_picture[0]){
ref_picture = s->current_picture_ptr->f.data;
}
--
GitLab