lavc/hevcdec: do not pass HEVCContext to ff_hevc_frame_nb_refs()

Pass the only things required from it - slice header and PPS -
explicitly.

Will be useful in the following commits to avoid mofiying HEVCContext in
hls_slice_header().

libavcodec/hevc/hevcdec.c

@@ -795,7 +795,7 @@ static int hls_slice_header(HEVCContext *s, GetBitContext *gb)
 
             sh->rpl_modification_flag[0] = 0;
             sh->rpl_modification_flag[1] = 0;
-            nb_refs = ff_hevc_frame_nb_refs(s);
+            nb_refs = ff_hevc_frame_nb_refs(sh, pps);
             if (!nb_refs) {
                 av_log(s->avctx, AV_LOG_ERROR, "Zero refs for a frame with P or B slices.\n");
                 return AVERROR_INVALIDDATA;

libavcodec/hevc/hevcdec.h

@@ -614,7 +614,7 @@ int ff_hevc_res_scale_sign_flag(HEVCLocalContext *lc, int idx);
 /**
  * Get the number of candidate references for the current frame.
  */
-int ff_hevc_frame_nb_refs(const HEVCContext *s);
+int ff_hevc_frame_nb_refs(const SliceHeader *sh, const HEVCPPS *pps);
 
 int ff_hevc_set_new_ref(HEVCContext *s, int poc);
 

libavcodec/hevc/refs.c

@@ -526,12 +526,12 @@ fail:
     return ret;
 }
 
-int ff_hevc_frame_nb_refs(const HEVCContext *s)
+int ff_hevc_frame_nb_refs(const SliceHeader *sh, const HEVCPPS *pps)
 {
     int ret = 0;
     int i;
-    const ShortTermRPS *rps = s->sh.short_term_rps;
-    const LongTermRPS *long_rps = &s->sh.long_term_rps;
+    const ShortTermRPS     *rps = sh->short_term_rps;
+    const LongTermRPS *long_rps = &sh->long_term_rps;
 
     if (rps) {
         for (i = 0; i < rps->num_negative_pics; i++)
@@ -545,7 +545,7 @@ int ff_hevc_frame_nb_refs(const HEVCContext *s)
             ret += !!long_rps->used[i];
     }
 
-    if (s->pps->pps_curr_pic_ref_enabled_flag)
+    if (pps->pps_curr_pic_ref_enabled_flag)
         ret++;
 
     return ret;

libavcodec/nvdec_hevc.c

@@ -187,7 +187,7 @@ static int nvdec_hevc_start_frame(AVCodecContext *avctx,
 
             .NumBitsForShortTermRPSInSlice                = s->sh.short_term_rps ? s->sh.short_term_ref_pic_set_size : 0,
             .NumDeltaPocsOfRefRpsIdx                      = s->sh.short_term_rps ? s->sh.short_term_rps->rps_idx_num_delta_pocs : 0,
-            .NumPocTotalCurr                              = ff_hevc_frame_nb_refs(s),
+            .NumPocTotalCurr                              = ff_hevc_frame_nb_refs(&s->sh, pps),
             .NumPocStCurrBefore                           = s->rps[ST_CURR_BEF].nb_refs,
             .NumPocStCurrAfter                            = s->rps[ST_CURR_AFT].nb_refs,
             .NumPocLtCurr                                 = s->rps[LT_CURR].nb_refs,

libavcodec/vdpau_hevc.c

@@ -205,7 +205,7 @@ static int vdpau_hevc_start_frame(AVCodecContext *avctx,
         }
     }
     /* See section 7.4.7.2 of the specification. */
-    info->NumPocTotalCurr = ff_hevc_frame_nb_refs(h);
+    info->NumPocTotalCurr = ff_hevc_frame_nb_refs(&h->sh, pps);
     if (sh->short_term_ref_pic_set_sps_flag == 0 && sh->short_term_rps) {
         /* Corresponds to specification field, NumDeltaPocs[RefRpsIdx].
            Only applicable when short_term_ref_pic_set_sps_flag == 0.