[FFmpeg-devel] [PATCH] avfilter/vf_scale: overwrite the width and eight expressions with the original values

[James Almer]

On 9/4/2022 11:55 PM, James Almer wrote:
> Instead of the potentially adjusted ones. Otherwise, if config_props() is
> called again and if using force_original_aspect_ratio, the already adjusted
> values could be altered again.
> 
> Example command line
> scale=size=1920x1000:force_original_aspect_ratio=decrease:force_divisible_by=2
> 
> user value 1920x1000 -> 1920x798 on init_dict() -> 1918x798 on frame
> change when eval_mode == EVAL_MODE_INIT, which after e645a1ddb9 could be at the
> very first frame.
> 
> Signed-off-by: James Almer <jamrial at gmail.com>
> ---
>   libavfilter/vf_scale.c | 20 ++++++++++----------
>   1 file changed, 10 insertions(+), 10 deletions(-)
> 
> diff --git a/libavfilter/vf_scale.c b/libavfilter/vf_scale.c
> index 996f7aaa5b..2b12cf283c 100644
> --- a/libavfilter/vf_scale.c
> +++ b/libavfilter/vf_scale.c
> @@ -491,19 +491,19 @@ static int config_props(AVFilterLink *outlink)
>       if ((ret = scale_eval_dimensions(ctx)) < 0)
>           goto fail;
>   
> -    ff_scale_adjust_dimensions(inlink, &scale->w, &scale->h,
> +    outlink->w = scale->w;
> +    outlink->h = scale->h;
> +
> +    ff_scale_adjust_dimensions(inlink, &outlink->w, &outlink->h,
>                                  scale->force_original_aspect_ratio,
>                                  scale->force_divisible_by);
>   
> -    if (scale->w > INT_MAX ||
> -        scale->h > INT_MAX ||
> -        (scale->h * inlink->w) > INT_MAX ||
> -        (scale->w * inlink->h) > INT_MAX)
> +    if (outlink->w > INT_MAX ||
> +        outlink->h > INT_MAX ||
> +        (outlink->h * inlink->w) > INT_MAX ||
> +        (outlink->w * inlink->h) > INT_MAX)
>           av_log(ctx, AV_LOG_ERROR, "Rescaled value for width or height is too big.\n");
>   
> -    outlink->w = scale->w;
> -    outlink->h = scale->h;
> -
>       /* TODO: make algorithm configurable */
>   
>       scale->input_is_pal = desc->flags & AV_PIX_FMT_FLAG_PAL;
> @@ -718,9 +718,9 @@ static int scale_frame(AVFilterLink *link, AVFrame *in, AVFrame **frame_out)
>               goto scale;
>   
>           if (scale->eval_mode == EVAL_MODE_INIT) {
> -            snprintf(buf, sizeof(buf)-1, "%d", outlink->w);
> +            snprintf(buf, sizeof(buf) - 1, "%d", scale->w);
>               av_opt_set(scale, "w", buf, 0);
> -            snprintf(buf, sizeof(buf)-1, "%d", outlink->h);
> +            snprintf(buf, sizeof(buf) - 1, "%d", scale->h);
>               av_opt_set(scale, "h", buf, 0);
>   
>               ret = scale_parse_expr(ctx, NULL, &scale->w_pexpr, "width", scale->w_expr);

Will apply.