[FFmpeg-devel] [PATCH] libavcodec/hevcdec: detect non-conformant missing refs

[Xiaolei Yu]

For cases which prefer rejecting broken bitstreams.
---
 libavcodec/hevc_refs.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/libavcodec/hevc_refs.c b/libavcodec/hevc_refs.c
index fe18ca2b1d..7ea70e301b 100644
--- a/libavcodec/hevc_refs.c
+++ b/libavcodec/hevc_refs.c
@@ -426,7 +426,7 @@ static HEVCFrame *generate_missing_ref(HEVCContext *s, int poc)
 
 /* add a reference with the given poc to the list and mark it as used in DPB */
 static int add_candidate_ref(HEVCContext *s, RefPicList *list,
-                             int poc, int ref_flag, uint8_t use_msb)
+                             int poc, int ref_flag, uint8_t use_msb, int maybe_missing)
 {
     HEVCFrame *ref = find_ref_idx(s, poc, use_msb);
 
@@ -434,6 +434,9 @@ static int add_candidate_ref(HEVCContext *s, RefPicList *list,
         return AVERROR_INVALIDDATA;
 
     if (!ref) {
+        if ((s->avctx->err_recognition & AV_EF_COMPLIANT) && !maybe_missing)
+            return AVERROR_INVALIDDATA;
+
         ref = generate_missing_ref(s, poc);
         if (!ref)
             return AVERROR(ENOMEM);
@@ -476,6 +479,7 @@ int ff_hevc_frame_rps(HEVCContext *s)
     for (i = 0; i < short_rps->num_delta_pocs; i++) {
         int poc = s->poc + short_rps->delta_poc[i];
         int list;
+        int maybe_missing;
 
         if (!short_rps->used[i])
             list = ST_FOLL;
@@ -484,7 +488,10 @@ int ff_hevc_frame_rps(HEVCContext *s)
         else
             list = ST_CURR_AFT;
 
-        ret = add_candidate_ref(s, &rps[list], poc, HEVC_FRAME_FLAG_SHORT_REF, 1);
+        maybe_missing = list != ST_CURR_BEF && list != ST_CURR_AFT;
+
+        ret = add_candidate_ref(s, &rps[list], poc, HEVC_FRAME_FLAG_SHORT_REF, 1,
+                                maybe_missing);
         if (ret < 0)
             goto fail;
     }
@@ -493,8 +500,10 @@ int ff_hevc_frame_rps(HEVCContext *s)
     for (i = 0; i < long_rps->nb_refs; i++) {
         int poc  = long_rps->poc[i];
         int list = long_rps->used[i] ? LT_CURR : LT_FOLL;
+        int maybe_missing = list != LT_CURR;
 
-        ret = add_candidate_ref(s, &rps[list], poc, HEVC_FRAME_FLAG_LONG_REF, long_rps->poc_msb_present[i]);
+        ret = add_candidate_ref(s, &rps[list], poc, HEVC_FRAME_FLAG_LONG_REF, long_rps->poc_msb_present[i],
+                                maybe_missing);
         if (ret < 0)
             goto fail;
     }
-- 
2.35.1