[FFmpeg-devel] [PATCH] Add scale filter

[Diego Biurrun]

On Wed, Oct 28, 2009 at 12:42:43AM +0100, Stefano Sabatini wrote:
> 
> --- /dev/null	1970-01-01 00:00:00.000000000 +0000
> +++ ffmpeg/libavfilter/vf_scale.c	2009-10-28 00:39:51.000000000 +0100
> @@ -0,0 +1,199 @@
> +
> +/**
> + * @file libavfilter/vf_scale.c
> + * video scale filter

video filter

> +    int hsub, vsub;             ///< chroma subsampling
> +    int slice_y;                ///< top of current output slice
> +    int slice_dir;              ///< the detected slice direction order for the current frame

s/the//

> +    /* sanity check parms */

parAms

> +    if (scale->w <  -1 || scale->h <  -1) {
> +        av_log(ctx, AV_LOG_ERROR, "Value for size less than -1 is not acceptable\n");

Size values less than -1 are not acceptable.

> +    if (w == -1)
> +        w = scale->h*link->src->inputs[0]->w/link->src->inputs[0]->h;
> +    if (h == -1)
> +        h = scale->w*link->src->inputs[0]->h/link->src->inputs[0]->w;

I think spaces around * and / would make this more readable.  At a first
glance I missed these operators.

> --- ffmpeg.orig/doc/libavfilter.texi	2009-10-27 21:13:14.000000000 +0100
> +++ ffmpeg/doc/libavfilter.texi	2009-10-27 23:17:40.000000000 +0100
> @@ -149,6 +149,29 @@
>  
> +If ``width'' or ``height'' is 0, the corresponding input size is
> +used.

Maybe I'm dumb, but I dunno which size corresponds in this case.

> --- ffmpeg.orig/libavfilter/allfilters.c	2009-10-27 20:53:12.000000000 +0100
> +++ ffmpeg/libavfilter/allfilters.c	2009-10-27 23:17:40.000000000 +0100
> @@ -39,4 +39,5 @@
>      REGISTER_FILTER (NOFORMAT,noformat,vf);
>      REGISTER_FILTER (NULL,null,vf);
>      REGISTER_FILTER (VFLIP,vflip,vf);
> +    REGISTER_FILTER (SCALE,scale,vf);

Ahem...

Diego