[FFmpeg-devel] [PATCH] vf_crop: add support for dar, sar, hsub, and vsub variables

[Stefano Sabatini]

On date Monday 2011-07-04 13:30:31 +0200, Stefano Sabatini encoded:
> This is consistent with the pad/scale filters.
> ---
>  doc/filters.texi      |   10 ++++++++++
>  libavfilter/vf_crop.c |   13 +++++++++++++
>  2 files changed, 23 insertions(+), 0 deletions(-)
> 
> diff --git a/doc/filters.texi b/doc/filters.texi
> index 9fde89c..7a7cd3b 100644
> --- a/doc/filters.texi
> +++ b/doc/filters.texi
> @@ -215,6 +215,16 @@ the output (cropped) width and heigth
>  @item ow, oh
>  same as @var{out_w} and @var{out_h}
>  
> + at item dar, a
> +input display aspect ratio, same as @var{iw} / @var{ih}
> +
> + at item sar
> +input sample aspect ratio
> +
> + at item hsub, vsub
> +horizontal and vertical chroma subsample values. For example for the
> +pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
> +
>  @item n
>  the number of input frame, starting from 0
>  
> diff --git a/libavfilter/vf_crop.c b/libavfilter/vf_crop.c
> index b9c60cb..baab7dc 100644
> --- a/libavfilter/vf_crop.c
> +++ b/libavfilter/vf_crop.c
> @@ -40,6 +40,10 @@ static const char *var_names[] = {
>      "in_h", "ih",   ///< height of the input video
>      "out_w", "ow",  ///< width  of the cropped video
>      "out_h", "oh",  ///< height of the cropped video
> +    "dar", "a",
> +    "sar",
> +    "hsub",
> +    "vsub",
>      "x",
>      "y",
>      "n",            ///< number of frame
> @@ -56,6 +60,10 @@ enum var_name {
>      VAR_IN_H,  VAR_IH,
>      VAR_OUT_W, VAR_OW,
>      VAR_OUT_H, VAR_OH,
> +    VAR_DAR, VAR_A,
> +    VAR_SAR,
> +    VAR_HSUB,
> +    VAR_VSUB,
>      VAR_X,
>      VAR_Y,
>      VAR_N,
> @@ -162,6 +170,11 @@ static int config_input(AVFilterLink *link)
>      crop->var_values[VAR_PI]    = M_PI;
>      crop->var_values[VAR_IN_W]  = crop->var_values[VAR_IW] = ctx->inputs[0]->w;
>      crop->var_values[VAR_IN_H]  = crop->var_values[VAR_IH] = ctx->inputs[0]->h;

> +    crop->var_values[VAR_DAR]   = crop->var_values[VAR_A]  = (float) link->w / link->h;

And I realized this is not right, DAR is SAR * W/H.
So what do you think it is better:

1) change the meaning of the "a" var in scale/pad to match the
implementation (a = inw/inh)

2) or change its meaning to match the documentation (a = dar)
?
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