[FFmpeg-devel] [PATCH] avfilter: add convolution filter

[Michael Niedermayer]

On Wed, Jul 15, 2015 at 07:48:52PM +0000, Paul B Mahol wrote:
> Signed-off-by: Paul B Mahol <onemda at gmail.com>
[...]
> +static void filter_3x3(ConvolutionContext *s, AVFrame *in, AVFrame *out, int plane)
> +{
> +    const uint8_t *src = in->data[plane];
> +    uint8_t *dst = out->data[plane];
> +    const int stride = in->linesize[plane];
> +    const int bstride = s->bstride;
> +    const int height = s->planeheight[plane];
> +    const int width  = s->planewidth[plane];
> +    uint8_t *p0 = s->buffer + 16;
> +    uint8_t *p1 = p0 + bstride;
> +    uint8_t *p2 = p1 + bstride;
> +    uint8_t *orig = p0, *end = p2;
> +    const int *matrix = s->matrix[plane];
> +    const float rdiv = s->rdiv;
> +    const float bias = s->bias;
> +    int y, x;
> +
> +    line_copy8(p0, src + stride, width, 1);
> +    line_copy8(p1, src, width, 1);
> +
> +    for (y = 0; y < height; y++) {
> +        src += stride * (y < height - 1 ? 1 : -1);
> +        line_copy8(p2, src, width, 1);
> +
> +        for (x = 0; x < width; x++) {
> +            int sum = p0[x - 1] * matrix[0] +
> +                      p0[x] *     matrix[1] +
> +                      p0[x + 1] * matrix[2] +
> +                      p1[x - 1] * matrix[3] +
> +                      p1[x] *     matrix[4] +
> +                      p1[x + 1] * matrix[5] +
> +                      p2[x - 1] * matrix[6] +
> +                      p2[x] *     matrix[7] +
> +                      p2[x + 1] * matrix[8];
> +            sum = (int)(sum * rdiv + bias + 0.5f);

> +            dst[x] = av_clip(sum, 0, 255);

could use av_clip_uint8()

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Why not whip the teacher when the pupil misbehaves? -- Diogenes of Sinope
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