[FFmpeg-devel] [PATCH] lavfi: remove the duplicate expression evaluation.

[Mark Thompson]

On 09/01/17 00:12, Jun Zhao wrote:
> From 80ea322e8bd634dbf93291f7a4d78bc87834c0a8 Mon Sep 17 00:00:00 2001
> From: Jun Zhao <mypopydev at gmail.com>
> Date: Sun, 8 Jan 2017 14:26:39 +0800
> Subject: [PATCH] lavfi: remove the duplicate expression evaluation.
> 
> remove the duplicate expression evaluation in crop/drawtext/overlay.
> 
> Signed-off-by: Jun Zhao <jun.zhao at intel.com>
> ---
>  libavfilter/vf_crop.c     | 1 -
>  libavfilter/vf_drawtext.c | 1 -
>  libavfilter/vf_overlay.c  | 1 -
>  3 files changed, 3 deletions(-)
> 
> diff --git a/libavfilter/vf_crop.c b/libavfilter/vf_crop.c
> index 85ea892..4a032d1 100644
> --- a/libavfilter/vf_crop.c
> +++ b/libavfilter/vf_crop.c
> @@ -262,7 +262,6 @@ static int filter_frame(AVFilterLink *link, AVFrame *frame)
>          NAN : av_frame_get_pkt_pos(frame);
>      s->var_values[VAR_X] = av_expr_eval(s->x_pexpr, s->var_values, NULL);
>      s->var_values[VAR_Y] = av_expr_eval(s->y_pexpr, s->var_values, NULL);
> -    s->var_values[VAR_X] = av_expr_eval(s->x_pexpr, s->var_values, NULL);
>  
>      normalize_double(&s->x, s->var_values[VAR_X]);
>      normalize_double(&s->y, s->var_values[VAR_Y]);
> diff --git a/libavfilter/vf_drawtext.c b/libavfilter/vf_drawtext.c
> index 649240b..a485362 100644
> --- a/libavfilter/vf_drawtext.c
> +++ b/libavfilter/vf_drawtext.c
> @@ -1288,7 +1288,6 @@ static int draw_text(AVFilterContext *ctx, AVFrame *frame,
>  
>      s->x = s->var_values[VAR_X] = av_expr_eval(s->x_pexpr, s->var_values, &s->prng);
>      s->y = s->var_values[VAR_Y] = av_expr_eval(s->y_pexpr, s->var_values, &s->prng);
> -    s->x = s->var_values[VAR_X] = av_expr_eval(s->x_pexpr, s->var_values, &s->prng);
>  
>      update_alpha(s);
>      update_color_with_alpha(s, &fontcolor  , s->fontcolor  );
> diff --git a/libavfilter/vf_overlay.c b/libavfilter/vf_overlay.c
> index 108a6fc..ea5889e 100644
> --- a/libavfilter/vf_overlay.c
> +++ b/libavfilter/vf_overlay.c
> @@ -159,7 +159,6 @@ static void eval_expr(AVFilterContext *ctx)
>  
>      s->var_values[VAR_X] = av_expr_eval(s->x_pexpr, s->var_values, NULL);
>      s->var_values[VAR_Y] = av_expr_eval(s->y_pexpr, s->var_values, NULL);
> -    s->var_values[VAR_X] = av_expr_eval(s->x_pexpr, s->var_values, NULL);
>      s->x = normalize_xy(s->var_values[VAR_X], s->hsub);
>      s->y = normalize_xy(s->var_values[VAR_Y], s->vsub);
>  }
> -- 
> 2.1.4

Isn't the point of this that you can have an expression for x which depends on y, or an expression for y which depends on x, working either way around?

- Mark