[FFmpeg-devel] [PATCH v3 2/4] lavc/hevcdec: do not let missing ref frames invovled in dpb process

[Fei Wang]

From: Xu Guangxin <guangxin.xu at intel.com>

We will generate a new frame for a missed reference. The frame can only
be used for reference. We assign an invalid decode sequence to it, so
it will not be involved in any dpb process.

Tested-by: Fei Wang <fei.w.wang at intel.com>
Signed-off-by: Fei Wang <fei.w.wang at intel.com>
Signed-off-by: Xu Guangxin <guangxin.xu at intel.com>
---
 libavcodec/hevc_refs.c | 16 ++++++++++++++--
 libavcodec/hevcdec.c   |  8 ++++----
 libavcodec/hevcdec.h   |  3 +++
 3 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/libavcodec/hevc_refs.c b/libavcodec/hevc_refs.c
index 2b0468d6c4..5282716a61 100644
--- a/libavcodec/hevc_refs.c
+++ b/libavcodec/hevc_refs.c
@@ -173,6 +173,16 @@ int ff_hevc_set_new_ref(HEVCContext *s, AVFrame **frame, int poc)
     return 0;
 }
 
+static void unref_missing_refs(HEVCContext *s)
+{
+    for (int i = 0; i < FF_ARRAY_ELEMS(s->DPB); i++) {
+         HEVCFrame *frame = &s->DPB[i];
+         if (frame->sequence == HEVC_SEQUENCE_COUNTER_INVALID) {
+             ff_hevc_unref_frame(s, frame, ~0);
+         }
+    }
+}
+
 int ff_hevc_output_frame(HEVCContext *s, AVFrame *out, int flush)
 {
     if (IS_IRAP(s) && s->no_rasl_output_flag == 1) {
@@ -233,7 +243,7 @@ int ff_hevc_output_frame(HEVCContext *s, AVFrame *out, int flush)
         }
 
         if (s->seq_output != s->seq_decode)
-            s->seq_output = (s->seq_output + 1) & 0xff;
+            s->seq_output = (s->seq_output + 1) & HEVC_SEQUENCE_COUNTER_MASK;
         else
             break;
     } while (1);
@@ -419,7 +429,7 @@ static HEVCFrame *generate_missing_ref(HEVCContext *s, int poc)
     }
 
     frame->poc      = poc;
-    frame->sequence = s->seq_decode;
+    frame->sequence = HEVC_SEQUENCE_COUNTER_INVALID;
     frame->flags    = 0;
 
     if (s->threads_type == FF_THREAD_FRAME)
@@ -463,6 +473,8 @@ int ff_hevc_frame_rps(HEVCContext *s)
         return 0;
     }
 
+    unref_missing_refs(s);
+
     /* clear the reference flags on all frames except the current one */
     for (i = 0; i < FF_ARRAY_ELEMS(s->DPB); i++) {
         HEVCFrame *frame = &s->DPB[i];
diff --git a/libavcodec/hevcdec.c b/libavcodec/hevcdec.c
index f222f20706..6544171cf0 100644
--- a/libavcodec/hevcdec.c
+++ b/libavcodec/hevcdec.c
@@ -569,7 +569,7 @@ static int hls_slice_header(HEVCContext *s)
     }
 
     if ((IS_IDR(s) || IS_BLA(s)) && sh->first_slice_in_pic_flag) {
-        s->seq_decode = (s->seq_decode + 1) & 0xff;
+        s->seq_decode = (s->seq_decode + 1) & HEVC_SEQUENCE_COUNTER_MASK;
         s->max_ra     = INT_MAX;
         if (IS_IDR(s))
             ff_hevc_clear_refs(s);
@@ -614,7 +614,7 @@ static int hls_slice_header(HEVCContext *s)
             return pix_fmt;
         s->avctx->pix_fmt = pix_fmt;
 
-        s->seq_decode = (s->seq_decode + 1) & 0xff;
+        s->seq_decode = (s->seq_decode + 1) & HEVC_SEQUENCE_COUNTER_MASK;
         s->max_ra     = INT_MAX;
     }
 
@@ -3266,7 +3266,7 @@ static int decode_nal_unit(HEVCContext *s, const H2645NAL *nal)
         break;
     case HEVC_NAL_EOS_NUT:
     case HEVC_NAL_EOB_NUT:
-        s->seq_decode = (s->seq_decode + 1) & 0xff;
+        s->seq_decode = (s->seq_decode + 1) & HEVC_SEQUENCE_COUNTER_MASK;
         s->max_ra     = INT_MAX;
         break;
     case HEVC_NAL_AUD:
@@ -3741,7 +3741,7 @@ static int hevc_update_thread_context(AVCodecContext *dst,
     s->threads_type        = s0->threads_type;
 
     if (s0->eos) {
-        s->seq_decode = (s->seq_decode + 1) & 0xff;
+        s->seq_decode = (s->seq_decode + 1) & HEVC_SEQUENCE_COUNTER_MASK;
         s->max_ra = INT_MAX;
     }
 
diff --git a/libavcodec/hevcdec.h b/libavcodec/hevcdec.h
index f6acf845ae..542adcf593 100644
--- a/libavcodec/hevcdec.h
+++ b/libavcodec/hevcdec.h
@@ -390,6 +390,9 @@ typedef struct DBParams {
 #define HEVC_FRAME_FLAG_LONG_REF  (1 << 2)
 #define HEVC_FRAME_FLAG_BUMPING   (1 << 3)
 
+#define HEVC_SEQUENCE_COUNTER_MASK 0xff
+#define HEVC_SEQUENCE_COUNTER_INVALID (HEVC_SEQUENCE_COUNTER_MASK + 1)
+
 typedef struct HEVCFrame {
     AVFrame *frame;
     AVFrame *frame_grain;
-- 
2.25.1