[FFmpeg-devel] [PATCH v2 1/4] lavc/vaapi_encode_h265: Add P frame to GPB frame support for hevc_vaapi

[Xiang, Haihao]

On Mon, 2022-02-21 at 10:13 +0800, Fei Wang wrote:
> From: Linjie Fu <linjie.fu at intel.com>
> 
> Use GPB frames to replace regular P frames if backend driver does not
> support it.
> 
> - GPB:
>     Generalized P and B picture. P frames replaced by B frames with
>     forward-predict only, L0 == L1. Normal B frames still have 2
>     different ref_lists and allow bi-prediction
> 
> Signed-off-by: Linjie Fu <linjie.fu at intel.com>
> Signed-off-by: Fei Wang <fei.w.wang at intel.com>
> ---
>  libavcodec/vaapi_encode.c      | 33 +++++++++++++++++++++++++++++++--
>  libavcodec/vaapi_encode.h      |  1 +
>  libavcodec/vaapi_encode_h265.c | 15 +++++++++++++++
>  3 files changed, 47 insertions(+), 2 deletions(-)
> 
> diff --git a/libavcodec/vaapi_encode.c b/libavcodec/vaapi_encode.c
> index 3bf379b1a0..95eca7c288 100644
> --- a/libavcodec/vaapi_encode.c
> +++ b/libavcodec/vaapi_encode.c
> @@ -1845,6 +1845,30 @@ static av_cold int
> vaapi_encode_init_gop_structure(AVCodecContext *avctx)
>          ref_l1 = attr.value >> 16 & 0xffff;
>      }
>  
> +    ctx->p_to_gpb = 0;
> +
> +#if VA_CHECK_VERSION(1, 9, 0)
> +    attr = (VAConfigAttrib) { VAConfigAttribPredictionDirection };
> +    vas = vaGetConfigAttributes(ctx->hwctx->display,
> +                                ctx->va_profile,
> +                                ctx->va_entrypoint,
> +                                &attr, 1);
> +    if (vas != VA_STATUS_SUCCESS) {
> +        av_log(avctx, AV_LOG_WARNING, "Failed to query prediction direction "
> +               "attribute: %d (%s).\n", vas, vaErrorStr(vas));
> +    } else if (attr.value == VA_ATTRIB_NOT_SUPPORTED) {
> +        av_log(avctx, AV_LOG_VERBOSE, "Driver does not report whether "
> +               "support GPB, use regular P frames.\n");
> +    } else {
> +        if (attr.value & VA_PREDICTION_DIRECTION_BI_NOT_EMPTY) {
> +            ctx->p_to_gpb = 1;
> +            av_log(avctx, AV_LOG_VERBOSE, "Use GPB B frames to replace "
> +                   "regular P frames.\n");
> +        } else
> +            av_log(avctx, AV_LOG_VERBOSE, "Use regular P frames.\n");
> +    }
> +#endif
> +
>      if (ctx->codec->flags & FLAG_INTRA_ONLY ||
>          avctx->gop_size <= 1) {
>          av_log(avctx, AV_LOG_VERBOSE, "Using intra frames only.\n");
> @@ -1861,8 +1885,13 @@ static av_cold int
> vaapi_encode_init_gop_structure(AVCodecContext *avctx)
>          ctx->p_per_i  = INT_MAX;
>          ctx->b_per_p  = 0;
>      } else {
> -        av_log(avctx, AV_LOG_VERBOSE, "Using intra, P- and B-frames "
> -               "(supported references: %d / %d).\n", ref_l0, ref_l1);
> +       if (ctx->p_to_gpb)
> +           av_log(avctx, AV_LOG_VERBOSE, "Using intra, GPB-B-frames and "
> +                  "B-frames (supported references: %d / %d).\n",
> +                  ref_l0, ref_l1);
> +       else
> +           av_log(avctx, AV_LOG_VERBOSE, "Using intra, P- and B-frames "
> +                  "(supported references: %d / %d).\n", ref_l0, ref_l1);
>          ctx->gop_size = avctx->gop_size;
>          ctx->p_per_i  = INT_MAX;
>          ctx->b_per_p  = avctx->max_b_frames;
> diff --git a/libavcodec/vaapi_encode.h b/libavcodec/vaapi_encode.h
> index b41604a883..61c5615eb8 100644
> --- a/libavcodec/vaapi_encode.h
> +++ b/libavcodec/vaapi_encode.h
> @@ -328,6 +328,7 @@ typedef struct VAAPIEncodeContext {
>      int idr_counter;
>      int gop_counter;
>      int end_of_stream;
> +    int p_to_gpb;
>  
>      // Whether the driver supports ROI at all.
>      int             roi_allowed;
> diff --git a/libavcodec/vaapi_encode_h265.c b/libavcodec/vaapi_encode_h265.c
> index e1dc53dfa9..ea45893508 100644
> --- a/libavcodec/vaapi_encode_h265.c
> +++ b/libavcodec/vaapi_encode_h265.c
> @@ -886,6 +886,7 @@ static int
> vaapi_encode_h265_init_slice_params(AVCodecContext *avctx,
>                                                 VAAPIEncodePicture *pic,
>                                                 VAAPIEncodeSlice *slice)
>  {
> +    VAAPIEncodeContext                *ctx = avctx->priv_data;
>      VAAPIEncodeH265Context           *priv = avctx->priv_data;
>      VAAPIEncodeH265Picture           *hpic = pic->priv_data;
>      const H265RawSPS                  *sps = &priv->raw_sps;
> @@ -908,6 +909,9 @@ static int
> vaapi_encode_h265_init_slice_params(AVCodecContext *avctx,
>  
>      sh->slice_type = hpic->slice_type;
>  
> +    if (sh->slice_type == HEVC_SLICE_P && ctx->p_to_gpb)
> +        sh->slice_type = HEVC_SLICE_B;
> +
>      sh->slice_pic_order_cnt_lsb = hpic->pic_order_cnt &
>          (1 << (sps->log2_max_pic_order_cnt_lsb_minus4 + 4)) - 1;
>  
> @@ -1066,6 +1070,9 @@ static int
> vaapi_encode_h265_init_slice_params(AVCodecContext *avctx,
>          av_assert0(pic->type == PICTURE_TYPE_P ||
>                     pic->type == PICTURE_TYPE_B);
>          vslice->ref_pic_list0[0] = vpic->reference_frames[0];
> +        if (ctx->p_to_gpb && pic->type == PICTURE_TYPE_P)
> +            // Reference for GPB B-frame, L0 == L1
> +            vslice->ref_pic_list1[0] = vpic->reference_frames[0];
>      }
>      if (pic->nb_refs >= 2) {
>          // Forward reference for B-frame.
> @@ -1073,6 +1080,14 @@ static int
> vaapi_encode_h265_init_slice_params(AVCodecContext *avctx,
>          vslice->ref_pic_list1[0] = vpic->reference_frames[1];
>      }
>  
> +    if (pic->type == PICTURE_TYPE_P && ctx->p_to_gpb) {
> +        vslice->slice_type = HEVC_SLICE_B;
> +        for (i = 0; i < FF_ARRAY_ELEMS(vslice->ref_pic_list0); i++) {
> +            vslice->ref_pic_list1[i].picture_id = vslice-
> >ref_pic_list0[i].picture_id;
> +            vslice->ref_pic_list1[i].flags      = vslice-
> >ref_pic_list0[i].flags;
> +        }
> +    }
> +
>      return 0;
>  }

Patchset LGTM, will apply

-Haihao

>