[FFmpeg-devel] [PATCH 4/6] avcodec/h264: keep track of which frames used gray references

[Hendrik Leppkes]

On Tue, Nov 14, 2023 at 6:21 PM Michael Niedermayer
<michael at niedermayer.cc> wrote:
>
> Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> ---
>  libavcodec/h264_picture.c |  1 +
>  libavcodec/h264_slice.c   | 19 ++++++++++++++++++-
>  libavcodec/h264dec.c      |  1 +
>  libavcodec/h264dec.h      |  4 ++++
>  4 files changed, 24 insertions(+), 1 deletion(-)
>
> diff --git a/libavcodec/h264_picture.c b/libavcodec/h264_picture.c
> index 691c61eea23..3234141dbd6 100644
> --- a/libavcodec/h264_picture.c
> +++ b/libavcodec/h264_picture.c
> @@ -96,6 +96,7 @@ static void h264_copy_picture_params(H264Picture *dst, const H264Picture *src)
>      dst->field_picture = src->field_picture;
>      dst->reference     = src->reference;
>      dst->recovered     = src->recovered;
> +    dst->gray          = src->gray;
>      dst->invalid_gap   = src->invalid_gap;
>      dst->sei_recovery_frame_cnt = src->sei_recovery_frame_cnt;
>      dst->mb_width      = src->mb_width;
> diff --git a/libavcodec/h264_slice.c b/libavcodec/h264_slice.c
> index 4861a2cabba..2c4ab89dae1 100644
> --- a/libavcodec/h264_slice.c
> +++ b/libavcodec/h264_slice.c
> @@ -457,6 +457,7 @@ int ff_h264_update_thread_context(AVCodecContext *dst,
>      h->poc.prev_frame_num        = h->poc.frame_num;
>
>      h->recovery_frame        = h1->recovery_frame;
> +    h->non_gray              = h1->non_gray;
>
>      return err;
>  }
> @@ -1544,11 +1545,14 @@ static int h264_field_start(H264Context *h, const H264SliceContext *sl,
>                  if (ret < 0)
>                      return ret;
>                  h->short_ref[0]->poc = prev->poc + 2U;
> +                h->short_ref[0]->gray = prev->gray;
>                  ff_thread_report_progress(&h->short_ref[0]->tf, INT_MAX, 0);
>                  if (h->short_ref[0]->field_picture)
>                      ff_thread_report_progress(&h->short_ref[0]->tf, INT_MAX, 1);
> -            } else if (!h->frame_recovered && !h->avctx->hwaccel)
> +            } else if (!h->frame_recovered && !h->avctx->hwaccel) {
>                  color_frame(h->short_ref[0]->f, c);
> +                h->short_ref[0]->gray = 1;
> +            }

While we can't color invalid frames for hwaccels easily, the flag
should perhaps still be applied, as they are equally invalid.
Thinking about this, maybe the name should be less the color we
happened to use for it, and more like "placeholder" or "invalid" or
anything like that?

>              h->short_ref[0]->frame_num = h->poc.prev_frame_num;
>          }
>      }
> @@ -2007,6 +2011,19 @@ static int h264_slice_init(H264Context *h, H264SliceContext *sl,
>                               (sl->ref_list[j][i].reference & 3);
>      }
>
> +    if (sl->slice_type_nos == AV_PICTURE_TYPE_I) {
> +        h->cur_pic_ptr->gray = 0;
> +        h->non_gray = 1;
> +    } else {
> +        int gray = 0;
> +        for (j = 0; j < sl->list_count; j++) {
> +            for (i = 0; i < sl->ref_count[j]; i++) {
> +                gray |= sl->ref_list[j][i].parent->gray;
> +            }
> +        }
> +        h->cur_pic_ptr->gray = gray;
> +    }
> +
>      if (h->avctx->debug & FF_DEBUG_PICT_INFO) {
>          av_log(h->avctx, AV_LOG_DEBUG,
>                 "slice:%d %c mb:%d %c%s%s frame:%d poc:%d/%d ref:%d/%d qp:%d loop:%d:%d:%d weight:%d%s %s\n",
> diff --git a/libavcodec/h264dec.c b/libavcodec/h264dec.c
> index ef9e60bbf33..7ea55db75dd 100644
> --- a/libavcodec/h264dec.c
> +++ b/libavcodec/h264dec.c
> @@ -492,6 +492,7 @@ static void h264_decode_flush(AVCodecContext *avctx)
>      ff_h264_unref_picture(&h->cur_pic);
>
>      h->mb_y = 0;
> +    h->non_gray = 0;
>
>      ff_h264_free_tables(h);
>      h->context_initialized = 0;
> diff --git a/libavcodec/h264dec.h b/libavcodec/h264dec.h
> index ede51951727..366626c056c 100644
> --- a/libavcodec/h264dec.h
> +++ b/libavcodec/h264dec.h
> @@ -154,6 +154,8 @@ typedef struct H264Picture {
>
>      /// RefStruct reference; its pointee is shared between decoding threads.
>      atomic_int *decode_error_flags;
> +
> +    int gray;
>  } H264Picture;
>
>  typedef struct H264Ref {
> @@ -567,6 +569,8 @@ typedef struct H264Context {
>      struct FFRefStructPool *ref_index_pool;
>      struct FFRefStructPool *decode_error_flags_pool;
>      int ref2frm[MAX_SLICES][2][64];     ///< reference to frame number lists, used in the loop filter, the first 2 are for -2,-1
> +
> +    int non_gray;                       ///< Did we encounter a intra frame after a gray gap frame
>  } H264Context;
>
>  extern const uint16_t ff_h264_mb_sizes[4];
> --
> 2.17.1
>
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