[FFmpeg-devel] [PATCH v2 2/4] lavc/hevcdec: do not let missing ref frames invovled in dpb process

[Xiang, Haihao]

On Tue, 2022-06-14 at 09:23 +0800, Fei Wang wrote:
> 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 | 14 +++++++++++++-
>  libavcodec/hevcdec.c   |  4 ++--
>  libavcodec/hevcdec.h   |  3 +++
>  3 files changed, 18 insertions(+), 3 deletions(-)
> 
> diff --git a/libavcodec/hevc_refs.c b/libavcodec/hevc_refs.c
> index 3f8fe1ef18..89053fd1a2 100644
> --- a/libavcodec/hevc_refs.c
> +++ b/libavcodec/hevc_refs.c
> @@ -172,6 +172,16 @@ 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_DECODE_SEQUENCE_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) {
> @@ -418,7 +428,7 @@ 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)
> @@ -462,6 +472,8 @@ 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 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;

I see 0xff is used in other places, could you replace it with
HEVC_DECODE_SEQUENCE_MASK too ?

Thanks
Haihao


>          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;