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Git pushed a commit to branch release/4.4
in repository ffmpeg.

commit c5baeda37e6f297a9a2ac134040f1db577e7c9bc
Author:     Michael Niedermayer <[email protected]>
AuthorDate: Thu Apr 30 18:06:32 2026 +0200
Commit:     Michael Niedermayer <[email protected]>
CommitDate: Tue May 5 18:55:14 2026 +0200

    avcodec/h264: recompute per-slice direct mode state for every slice
    
    Regression since: 7f05c5cea04112471d8147487aa3b44141922d09
    Fixes: poc10
    Fixes: null pointer dereference
    
    Reported-by: Dale Curtis <[email protected]>
    Signed-off-by: Michael Niedermayer <[email protected]>
    (cherry picked from commit 17723863922bd80e29cc957507cef7ae79eddccb)
    Signed-off-by: Michael Niedermayer <[email protected]>
---
 libavcodec/h264_direct.c | 34 +++++++++++++++++++---------------
 libavcodec/h264_slice.c  |  3 +--
 2 files changed, 20 insertions(+), 17 deletions(-)

diff --git a/libavcodec/h264_direct.c b/libavcodec/h264_direct.c
index 8f07981130..3dd83413c1 100644
--- a/libavcodec/h264_direct.c
+++ b/libavcodec/h264_direct.c
@@ -122,26 +122,30 @@ void ff_h264_direct_ref_list_init(const H264Context 
*const h, H264SliceContext *
 {
     H264Ref *const ref1 = &sl->ref_list[1][0];
     H264Picture *const cur = h->cur_pic_ptr;
-    int list, j, field;
+    int list, field;
     int sidx     = (h->picture_structure & 1) ^ 1;
     int ref1sidx = (ref1->reference      & 1) ^ 1;
 
-    for (list = 0; list < sl->list_count; list++) {
-        cur->ref_count[sidx][list] = sl->ref_count[list];
-        for (j = 0; j < sl->ref_count[list]; j++)
-            cur->ref_poc[sidx][list][j] = 4 * 
sl->ref_list[list][j].parent->frame_num +
-                                          (sl->ref_list[list][j].reference & 
3);
-    }
+    /* Updates to cur_pic are not safe once ff_thread_finish_setup() has been
+     * called (other threads may already be reading these fields). */
+    if (!h->setup_finished) {
+        for (list = 0; list < sl->list_count; list++) {
+            cur->ref_count[sidx][list] = sl->ref_count[list];
+            for (int j = 0; j < sl->ref_count[list]; j++)
+                cur->ref_poc[sidx][list][j] = 4 * 
sl->ref_list[list][j].parent->frame_num +
+                                                 
(sl->ref_list[list][j].reference & 3);
+        }
 
-    if (h->picture_structure == PICT_FRAME) {
-        memcpy(cur->ref_count[1], cur->ref_count[0], 
sizeof(cur->ref_count[0]));
-        memcpy(cur->ref_poc[1],   cur->ref_poc[0],   sizeof(cur->ref_poc[0]));
-    }
+        if (h->picture_structure == PICT_FRAME) {
+            memcpy(cur->ref_count[1], cur->ref_count[0], 
sizeof(cur->ref_count[0]));
+            memcpy(cur->ref_poc[1],   cur->ref_poc[0],   
sizeof(cur->ref_poc[0]));
+        }
 
-    if (h->current_slice == 0) {
-        cur->mbaff = FRAME_MBAFF(h);
-    } else {
-        av_assert0(cur->mbaff == FRAME_MBAFF(h));
+        if (h->current_slice == 0) {
+            cur->mbaff = FRAME_MBAFF(h);
+        } else {
+            av_assert0(cur->mbaff == FRAME_MBAFF(h));
+        }
     }
 
     sl->col_fieldoff = 0;
diff --git a/libavcodec/h264_slice.c b/libavcodec/h264_slice.c
index a098f13037..7e8ca89505 100644
--- a/libavcodec/h264_slice.c
+++ b/libavcodec/h264_slice.c
@@ -1990,8 +1990,7 @@ static int h264_slice_init(H264Context *h, 
H264SliceContext *sl,
 
     if (sl->slice_type_nos == AV_PICTURE_TYPE_B && !sl->direct_spatial_mv_pred)
         ff_h264_direct_dist_scale_factor(h, sl);
-    if (!h->setup_finished)
-        ff_h264_direct_ref_list_init(h, sl);
+    ff_h264_direct_ref_list_init(h, sl);
 
     if (h->avctx->skip_loop_filter >= AVDISCARD_ALL ||
         (h->avctx->skip_loop_filter >= AVDISCARD_NONKEY &&

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