[FFmpeg-devel] [PATCH 3/6] vaapi_encode_h265: Don't require uniform_spacing_flag

[Xiang, Haihao]

On Tue, 2020-07-28 at 23:50 +0100, Mark Thompson wrote:
> Though still use it if the tile arrangement matches.  Also try to keep the
> fields in the same order as the standard.
> ---
>  libavcodec/vaapi_encode_h265.c | 39 ++++++++++++++++++++++++----------
>  1 file changed, 28 insertions(+), 11 deletions(-)
> 
> diff --git a/libavcodec/vaapi_encode_h265.c b/libavcodec/vaapi_encode_h265.c
> index 04bd2bef1d..a7230a676c 100644
> --- a/libavcodec/vaapi_encode_h265.c
> +++ b/libavcodec/vaapi_encode_h265.c
> @@ -555,23 +555,40 @@ static int
> vaapi_encode_h265_init_sequence_params(AVCodecContext *avctx)
>      pps->cu_qp_delta_enabled_flag = (ctx->va_rc_mode != VA_RC_CQP);
>      pps->diff_cu_qp_delta_depth   = 0;
>  
> -    pps->pps_loop_filter_across_slices_enabled_flag = 1;
> -
>      if (ctx->tile_rows && ctx->tile_cols) {
> -        pps->tiles_enabled_flag         = 1;
> -        pps->uniform_spacing_flag       = 1;
> -
> -        pps->num_tile_rows_minus1       = ctx->tile_rows - 1;
> -        pps->num_tile_columns_minus1    = ctx->tile_cols - 1;
> -
> -        pps->loop_filter_across_tiles_enabled_flag = 1;
> +        int uniform_spacing;
> +
> +        pps->tiles_enabled_flag      = 1;
> +        pps->num_tile_columns_minus1 = ctx->tile_cols - 1;
> +        pps->num_tile_rows_minus1    = ctx->tile_rows - 1;
> +
> +        // Test whether the spacing provided matches the H.265 uniform
> +        // spacing, and set the flag if it does.
> +        uniform_spacing = 1;
> +        for (i = 0; i <= pps->num_tile_columns_minus1; i++) {

Better to use 'i <= pps->num_tile_columns_minus1 && uniform_spacing' to allow
early-exiting the loop if uniform_spacing has been 0


> +            if (ctx->col_width[i] !=
> +                (i + 1) * ctx->slice_block_cols / ctx->tile_cols -
> +                 i      * ctx->slice_block_cols / ctx->tile_cols)
> +                uniform_spacing = 0;
> +        }
> +        for (i = 0; i <= pps->num_tile_rows_minus1; i++) {

Same as above. 

> +            if (ctx->row_height[i] !=
> +                (i + 1) * ctx->slice_block_rows / ctx->tile_rows -
> +                 i      * ctx->slice_block_rows / ctx->tile_rows)
> +                uniform_spacing = 0;
> +        }
> +        pps->uniform_spacing_flag = uniform_spacing;
>  
> -        for (i = 0; i <= pps->num_tile_rows_minus1; i++)
> -            pps->row_height_minus1[i]   = ctx->row_height[i] - 1;
>          for (i = 0; i <= pps->num_tile_columns_minus1; i++)
>              pps->column_width_minus1[i] = ctx->col_width[i] - 1;
> +        for (i = 0; i <= pps->num_tile_rows_minus1; i++)
> +            pps->row_height_minus1[i]   = ctx->row_height[i] - 1;
> +
> +        pps->loop_filter_across_tiles_enabled_flag = 1;
>      }
>  
> +    pps->pps_loop_filter_across_slices_enabled_flag = 1;
> +
>      // Fill VAAPI parameter buffers.
>  
>      *vseq = (VAEncSequenceParameterBufferHEVC) {