hevc: add support for bumping process

cherry picked from commit 8aa2fb7df3cffc67a3fd03a3a7eb49dbed4094c7
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/hevc.c

@@ -2601,6 +2601,9 @@ static int hevc_frame_start(HEVCContext *s)
 
     s->frame->pict_type = 3 - s->sh.slice_type;
 
+    if (!IS_IRAP(s))
+        ff_hevc_bump_frame(s);
+
     av_frame_unref(s->output_frame);
     ret = ff_hevc_output_frame(s, s->output_frame, 0);
     if (ret < 0)

libavcodec/hevc.h

@@ -719,6 +719,7 @@ typedef struct DBParams {
 #define HEVC_FRAME_FLAG_OUTPUT    (1 << 0)
 #define HEVC_FRAME_FLAG_SHORT_REF (1 << 1)
 #define HEVC_FRAME_FLAG_LONG_REF  (1 << 2)
+#define HEVC_FRAME_FLAG_BUMPING   (1 << 3)
 
 typedef struct HEVCFrame {
     AVFrame *frame;
@@ -1016,6 +1017,8 @@ int ff_hevc_set_new_ref(HEVCContext *s, AVFrame **frame, int poc);
  */
 int ff_hevc_output_frame(HEVCContext *s, AVFrame *frame, int flush);
 
+void ff_hevc_bump_frame(HEVCContext *s);
+
 void ff_hevc_unref_frame(HEVCContext *s, HEVCFrame *frame, int flags);
 
 void ff_hevc_set_neighbour_available(HEVCContext *s, int x0, int y0,

libavcodec/hevc_refs.c

@@ -166,9 +166,9 @@ int ff_hevc_output_frame(HEVCContext *s, AVFrame *out, int flush)
         if (s->sh.no_output_of_prior_pics_flag == 1) {
             for (i = 0; i < FF_ARRAY_ELEMS(s->DPB); i++) {
                 HEVCFrame *frame = &s->DPB[i];
-                if ((frame->flags & HEVC_FRAME_FLAG_OUTPUT) && frame->poc != s->poc &&
+                if (!(frame->flags & HEVC_FRAME_FLAG_BUMPING) && frame->poc != s->poc &&
                         frame->sequence == s->seq_output) {
-                    frame->flags &= ~(HEVC_FRAME_FLAG_OUTPUT);
+                    ff_hevc_unref_frame(s, frame, HEVC_FRAME_FLAG_OUTPUT);
                 }
             }
         }
@@ -198,7 +198,10 @@ int ff_hevc_output_frame(HEVCContext *s, AVFrame *out, int flush)
             int pixel_shift = !!(desc->comp[0].depth_minus1 > 7);
 
             ret = av_frame_ref(out, src);
-            ff_hevc_unref_frame(s, frame, HEVC_FRAME_FLAG_OUTPUT);
+            if (frame->flags & HEVC_FRAME_FLAG_BUMPING)
+                ff_hevc_unref_frame(s, frame, HEVC_FRAME_FLAG_OUTPUT | HEVC_FRAME_FLAG_BUMPING);
+            else
+                ff_hevc_unref_frame(s, frame, HEVC_FRAME_FLAG_OUTPUT);
             if (ret < 0)
                 return ret;
 
@@ -223,6 +226,46 @@ int ff_hevc_output_frame(HEVCContext *s, AVFrame *out, int flush)
     return 0;
 }
 
+void ff_hevc_bump_frame(HEVCContext *s)
+{
+    int dpb = 0;
+    int min_poc = INT_MAX;
+    int i;
+
+    for (i = 0; i < FF_ARRAY_ELEMS(s->DPB); i++) {
+        HEVCFrame *frame = &s->DPB[i];
+        if ((frame->flags) &&
+            frame->sequence == s->seq_output &&
+            frame->poc != s->poc) {
+            dpb++;
+        }
+    }
+
+    if (s->sps && dpb >= s->sps->temporal_layer[s->sps->max_sub_layers - 1].max_dec_pic_buffering) {
+        for (i = 0; i < FF_ARRAY_ELEMS(s->DPB); i++) {
+            HEVCFrame *frame = &s->DPB[i];
+            if ((frame->flags) &&
+                frame->sequence == s->seq_output &&
+                frame->poc != s->poc) {
+                if (frame->flags == HEVC_FRAME_FLAG_OUTPUT && frame->poc < min_poc) {
+                    min_poc = frame->poc;
+                }
+            }
+        }
+
+        for (i = 0; i < FF_ARRAY_ELEMS(s->DPB); i++) {
+            HEVCFrame *frame = &s->DPB[i];
+            if (frame->flags & HEVC_FRAME_FLAG_OUTPUT &&
+                frame->sequence == s->seq_output &&
+                frame->poc <= min_poc) {
+                frame->flags |= HEVC_FRAME_FLAG_BUMPING;
+            }
+        }
+
+        dpb--;
+    }
+}
+
 static int init_slice_rpl(HEVCContext *s)
 {
     HEVCFrame *frame = s->ref;