[FFmpeg-devel] [PATCH v1 07/13] lavc/hevc: Update reference list for SCC

[Fei Wang]

From: Linjie Fu <linjie.fu at intel.com>

Screen Content Coding allows non-intra slice in an IRAP frame which can
reference the frame itself, and would mark the current decoded picture
as "used for long-term reference", no matter TwoVersionsOfCurrDecPicFlag(8.1.3),
hence some previous restricts are not suitable any more.

Constructe RefPicListTemp and RefPicList according to 8-8/9/10. Disable
slice decoding for SCC profile to avoid unexpected error in hevc native
decoder and patch welcome.

Signed-off-by: Linjie Fu <linjie.justin.fu at gmail.com>
Signed-off-by: Fei Wang <fei.w.wang at intel.com>
---
 libavcodec/hevc_refs.c | 21 ++++++++++++++++++++-
 libavcodec/hevcdec.c   | 10 +++++++++-
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/libavcodec/hevc_refs.c b/libavcodec/hevc_refs.c
index 811e8feff8..96153a2459 100644
--- a/libavcodec/hevc_refs.c
+++ b/libavcodec/hevc_refs.c
@@ -322,7 +322,7 @@ int ff_hevc_slice_rpl(HEVCContext *s)
         return ret;
 
     if (!(s->rps[ST_CURR_BEF].nb_refs + s->rps[ST_CURR_AFT].nb_refs +
-          s->rps[LT_CURR].nb_refs)) {
+          s->rps[LT_CURR].nb_refs) && !s->ps.pps->pps_curr_pic_ref_enabled_flag) {
         av_log(s->avctx, AV_LOG_ERROR, "Zero refs in the frame RPS.\n");
         return AVERROR_INVALIDDATA;
     }
@@ -349,6 +349,13 @@ int ff_hevc_slice_rpl(HEVCContext *s)
                     rpl_tmp.nb_refs++;
                 }
             }
+            // Construct RefPicList0, RefPicList1 (8-8, 8-10)
+            if (s->ps.pps->pps_curr_pic_ref_enabled_flag) {
+                rpl_tmp.list[rpl_tmp.nb_refs]           = s->ref->poc;
+                rpl_tmp.ref[rpl_tmp.nb_refs]            = s->ref;
+                rpl_tmp.isLongTerm[rpl_tmp.nb_refs]     = 1;
+                rpl_tmp.nb_refs++;
+            }
         }
 
         /* reorder the references if necessary */
@@ -371,6 +378,14 @@ int ff_hevc_slice_rpl(HEVCContext *s)
             rpl->nb_refs = FFMIN(rpl->nb_refs, sh->nb_refs[list_idx]);
         }
 
+        // 8-9
+        if (s->ps.pps->pps_curr_pic_ref_enabled_flag &&
+            !sh->rpl_modification_flag[list_idx] &&
+            rpl_tmp.nb_refs > sh->nb_refs[L0]) {
+            rpl->list[sh->nb_refs[L0] - 1] = s->ref->poc;
+            rpl->ref[sh->nb_refs[L0] - 1]  = s->ref;
+        }
+
         if (sh->collocated_list == list_idx &&
             sh->collocated_ref_idx < rpl->nb_refs)
             s->ref->collocated_ref = rpl->ref[sh->collocated_ref_idx];
@@ -541,5 +556,9 @@ int ff_hevc_frame_nb_refs(const HEVCContext *s)
         for (i = 0; i < long_rps->nb_refs; i++)
             ret += !!long_rps->used[i];
     }
+
+    if (s->ps.pps->pps_curr_pic_ref_enabled_flag)
+        ret++;
+
     return ret;
 }
diff --git a/libavcodec/hevcdec.c b/libavcodec/hevcdec.c
index 50e7fd4465..bd8199d1dd 100644
--- a/libavcodec/hevcdec.c
+++ b/libavcodec/hevcdec.c
@@ -669,7 +669,8 @@ static int hls_slice_header(HEVCContext *s)
                    sh->slice_type);
             return AVERROR_INVALIDDATA;
         }
-        if (IS_IRAP(s) && sh->slice_type != HEVC_SLICE_I) {
+        if (IS_IRAP(s) && sh->slice_type != HEVC_SLICE_I &&
+            !s->ps.pps->pps_curr_pic_ref_enabled_flag) {
             av_log(s->avctx, AV_LOG_ERROR, "Inter slices in an IRAP frame.\n");
             return AVERROR_INVALIDDATA;
         }
@@ -3256,6 +3257,13 @@ static int decode_nal_unit(HEVCContext *s, const H2645NAL *nal)
             if (ret < 0)
                 goto fail;
         } else {
+            if (s->avctx->profile == FF_PROFILE_HEVC_SCC) {
+                av_log(s->avctx, AV_LOG_ERROR,
+                       "SCC profile is not yet implemented in hevc native decoder.\n");
+                ret = AVERROR_PATCHWELCOME;
+                goto fail;
+            }
+
             if (s->threads_number > 1 && s->sh.num_entry_point_offsets > 0)
                 ctb_addr_ts = hls_slice_data_wpp(s, nal);
             else
-- 
2.25.1