[FFmpeg-devel] [PATCH] make width and height available as parameters in vf_scale

[Stefano Sabatini]

On date Wednesday 2010-05-19 14:00:31 -0700, Baptiste Coudurier encoded:
> Hi
> 
> $subject.
> 
> -- 
> Baptiste COUDURIER
> Key fingerprint                 8D77134D20CC9220201FC5DB0AC9325C5C1ABAAA
> FFmpeg maintainer                                  http://www.ffmpeg.org

> Index: libavfilter/vf_scale.c
> ===================================================================
> --- libavfilter/vf_scale.c	(revision 23157)
> +++ libavfilter/vf_scale.c	(working copy)
> @@ -24,9 +24,22 @@
>   */
>  
>  #include "avfilter.h"
> +#include "libavcodec/eval.h"
>  #include "libavutil/pixdesc.h"
>  #include "libswscale/swscale.h"
>  
> +static const char *var_names[] = {
> +    "w",    ///< width of the main video
> +    "h",    ///< height of the main video
> +    NULL
> +};
> +
> +enum var_name {
> +    W,
> +    H,
> +    VARS_NB,
> +};
> +
>  typedef struct {
>      struct SwsContext *sws;     ///< software scaler context
>  
> @@ -41,6 +54,7 @@
>      int hsub, vsub;             ///< chroma subsampling
>      int slice_y;                ///< top of current output slice
>      int input_is_pal;           ///< set to 1 if the input format is paletted
> +    char w_expr[255], h_expr[255];
>  } ScaleContext;
>  
>  static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
> @@ -50,19 +64,12 @@
>  
>      scale->flags = SWS_BILINEAR;
>      if (args){
> -        sscanf(args, "%d:%d", &scale->w, &scale->h);
> +        sscanf(args, "%255[^:]:%255[^:]", scale->w_expr, scale->h_expr);
>          p= strstr(args,"flags=");
>          if(p) scale->flags= strtoul(p+6, NULL, 0);
> +        av_log(ctx, AV_LOG_INFO, "flags %#x\n", scale->flags);

Unrelated, also IIRC I added a similar log.

>      }
>  
> -    /* sanity check params */
> -    if (scale->w <  -1 || scale->h <  -1) {
> -        av_log(ctx, AV_LOG_ERROR, "Size values less than -1 are not acceptable.\n");
> -        return -1;
> -    }
> -    if (scale->w == -1 && scale->h == -1)
> -        scale->w = scale->h = 0;
> -
>      return 0;
>  }
>  
> @@ -110,6 +117,31 @@
>      ScaleContext *scale = ctx->priv;
>      int64_t w, h;
>  
> +    const char *error = NULL, *expr;
> +    double var_values[VARS_NB];
> +
> +    /* Finish the configuration by evaluating the expressions
> +       now when both inputs are configured. */
> +    var_values[W]    = ctx->inputs[0]->w;
> +    var_values[H]    = ctx->inputs[0]->h;
> +

> +    scale->w = ff_parse_and_eval_expr((expr = scale->w_expr), var_names, var_values,
> +                                      NULL, NULL, NULL, NULL, NULL, &error);
> +    if (error)
> +        return -1;
> +    scale->h = ff_parse_and_eval_expr((expr = scale->h_expr), var_names, var_values,
> +                                      NULL, NULL, NULL, NULL, NULL, &error);
> +    if (error)
> +        return -1;
> +
> +    /* sanity check params */
> +    if (scale->w < -1 || scale->h < -1) {
> +        av_log(ctx, AV_LOG_ERROR, "Size values less than -1 are not acceptable.\n");
> +        return -1;
> +    }

Should be updated to the new API and return AVERROR(EINVAL).

> +    if (scale->w == -1 && scale->h == -1)
> +        scale->w = scale->h = 0;
> +
>      if (!(w = scale->w))
>          w = inlink->w;
>      if (!(h = scale->h))

Regards.
-- 
FFmpeg = Fast & Fancy Mastodontic Practical Epic Glue