[FFmpeg-devel] [PATCH] Add crop filter

[Michael Niedermayer]

On Wed, Oct 14, 2009 at 08:49:16PM +0200, Stefano Sabatini wrote:
> On date Wednesday 2009-10-14 01:37:46 +0200, Michael Niedermayer encoded:
> > On Tue, Oct 13, 2009 at 08:47:09PM +0200, Stefano Sabatini wrote:
> > > On date Tuesday 2009-10-13 13:16:29 +0200, Michael Niedermayer encoded:
> > > > On Mon, Oct 12, 2009 at 08:41:08PM +0200, Stefano Sabatini wrote:
> > > > > On date Monday 2009-10-12 09:28:29 +0200, Michael Niedermayer encoded:
> > [...]
> > > +    if (link->format == PIX_FMT_MONOWHITE || link->format == PIX_FMT_MONOBLACK) {
> > > +        crop->x &= ~7;
> > > +        crop->y &= ~7;
> > > +        crop->w &= ~7;
> > > +        crop->h &= ~7;
> > 
> > the y/h changes are wrong
> 
> Fixed, and factorized the following (ab)using the crop->hsub field.

hacks requires a comment in the code at least


[...]
> +static int config_input(AVFilterLink *link)
> +{
> +    AVFilterContext *ctx = link->dst;
> +    CropContext *crop = ctx->priv;
> +
> +    if (crop->w == 0)
> +        crop->w = link->w - crop->x;
> +    if (crop->h == 0)
> +        crop->h = link->h - crop->y;
> +
> +    if (crop->x < 0 || crop->y < 0                      ||

> +        crop->w < 0 || crop->h < 0                      ||

<=


> +        (unsigned)crop->x + (unsigned)crop->w > link->w ||
> +        (unsigned)crop->y + (unsigned)crop->h > link->h) {
> +        av_log(ctx, AV_LOG_ERROR,
> +               "Output area %d:%d:%d:%d not within the input area 0:0:%d:%d\n",
> +               crop->x, crop->y, crop->w, crop->h, link->w, link->h);
> +        return -1;
> +    }
[...]
> +
> +    crop->x &= ~((1 << crop->hsub) - 1);
> +    crop->y &= ~((1 << crop->vsub) - 1);
> +    crop->w &= ~((1 << crop->hsub) - 1);
> +    crop->h &= ~((1 << crop->vsub) - 1);
> +
> +    av_log(link->dst, AV_LOG_INFO, "x:%d y:%d w:%d h:%d\n", crop->x, crop->y, crop->w, crop->h);
> +
> +    if (crop->w == 0 || crop->h == 0) {
> +        av_log(link->dst, AV_LOG_ERROR, "Size values too small\n");
> +        return -1;
> +    }

please move the check at the end, dont check and the change and then check
again. or dont round at all and rather complain that the value is not ok


[...]
> +static void draw_slice(AVFilterLink *link, int y, int h)
> +{
> +    AVFilterContext *ctx = link->dst;
> +    CropContext *crop = ctx->priv;
> +
> +    int y1 = y;
> +    int h1 = h;

why these variables?


[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

it is not once nor twice but times without number that the same ideas make
their appearance in the world. -- Aristotle
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