[FFmpeg-devel] [PATCH] Add pad filter

[Diego Biurrun]

On Sun, Nov 08, 2009 at 09:50:13PM +0100, Stefano Sabatini wrote:
> 
> --- ffmpeg.orig/libavfilter/allfilters.c	2009-11-08 21:38:43.000000000 +0100
> +++ ffmpeg/libavfilter/allfilters.c	2009-11-08 21:38:47.000000000 +0100
> @@ -38,6 +38,7 @@
>      REGISTER_FILTER (NOFORMAT, noformat, vf);
>      REGISTER_FILTER (NULL, null, vf);
> +    REGISTER_FILTER (PAD,  pad, vf);
>      REGISTER_FILTER (SCALE, scale, vf);
>      REGISTER_FILTER (SLICIFY, slicify, vf);

What is the 'vf' for anyway?


> --- /dev/null	1970-01-01 00:00:00.000000000 +0000
> +++ ffmpeg/libavfilter/vf_pad.c	2009-11-08 21:38:47.000000000 +0100
> @@ -0,0 +1,329 @@
> +
> +/**
> + * @file libavfilter/vf_pad.c
> + * video pad filter

"video padding" sounds better to my ears.

> +static AVFilterPicRef *get_video_buffer(AVFilterLink *link, int perms, int w, int h)

needlessly long line (in other places as well)

> +    picref->data[0] +=  pad->x             + (pad->y * picref->linesize[0]);
> +    picref->data[1] += (pad->x>>pad->hsub) + (pad->y * picref->linesize[1]>>pad->vsub);
> +    picref->data[2] += (pad->x>>pad->hsub) + (pad->y * picref->linesize[2]>>pad->vsub);

I think spaces around >> would greatly aid readability here (and in
other places).

> --- ffmpeg.orig/doc/libavfilter.texi	2009-11-08 21:38:43.000000000 +0100
> +++ ffmpeg/doc/libavfilter.texi	2009-11-08 21:38:47.000000000 +0100
> @@ -145,6 +145,59 @@
>  
> + at section pad
> +
> +Add pads at the unscaled border and places the unscaled original at

s/pads/padding/

> +size. Default expressions are respectively ``(out_w-in_w)/2'' and

I think "are respectively" is always wrong word ordering.  You can flag
this mentally as a mistake.  Also, I think you can drop most uses of the
word "respectively" from your sentences.

> +All the expressions can contains the constants "PI", and "E".

contain

> +adds a 50 pixels red border to the bottom of the picture.

pixel

Diego