[FFmpeg-devel] [PATCH v1 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: Xu Guangxin <guangxin.xu at intel.com>
---
 libavcodec/hevc_refs.c | 13 ++++++++++++-
 libavcodec/hevcdec.c   |  4 ++--
 libavcodec/hevcdec.h   |  3 +++
 3 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/libavcodec/hevc_refs.c b/libavcodec/hevc_refs.c
index 3f8fe1ef18..3ea2fb6c0b 100644
--- a/libavcodec/hevc_refs.c
+++ b/libavcodec/hevc_refs.c
@@ -172,8 +172,19 @@ 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_DECODE_SEQUENCE_INVALID) {
+             ff_hevc_unref_frame(s, frame, ~0);
+         }
+    }
+}
+
 int ff_hevc_output_frame(HEVCContext *s, AVFrame *out, int flush)
 {
+    unref_missing_refs(s);
     if (IS_IRAP(s) && s->no_rasl_output_flag == 1) {
         const static int mask = HEVC_FRAME_FLAG_BUMPING | HEVC_FRAME_FLAG_OUTPUT;
         for (int i = 0; i < FF_ARRAY_ELEMS(s->DPB); i++) {
@@ -418,7 +429,7 @@ static HEVCFrame *generate_missing_ref(HEVCContext *s, int poc)
     }
 
     frame->poc      = poc;
-    frame->sequence = s->seq_decode;
+    frame->sequence = HEVC_DECODE_SEQUENCE_INVALID;
     frame->flags    = 0;
 
     if (s->threads_type == FF_THREAD_FRAME)
diff --git a/libavcodec/hevcdec.c b/libavcodec/hevcdec.c
index f782ea6394..99785aa5d1 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_DECODE_SEQUENCE_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_DECODE_SEQUENCE_MASK;
         s->max_ra     = INT_MAX;
     }
 
diff --git a/libavcodec/hevcdec.h b/libavcodec/hevcdec.h
index de861b88b3..9c8bcefb48 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_DECODE_SEQUENCE_MASK 0xff
+#define HEVC_DECODE_SEQUENCE_INVALID (HEVC_DECODE_SEQUENCE_MASK + 1)
+
 typedef struct HEVCFrame {
     AVFrame *frame;
     AVFrame *frame_grain;
-- 
2.25.1