[SDK] AE - How to simply iterate over Pixel

But with

static PF_Err Render(
	PF_InData		*in_data,
	PF_OutData		*out_data,
	PF_ParamDef		*params[],
	PF_LayerDef		*output )
{
PF_LayerDef* in_layer = &params[0]->u.ld;
for(int pixel = 0; pixel <= 1000; pixel++) {
        PF_GET_PIXEL_DATA8 ( in_layer, in_layer->data + pixel, &in_buf );
        PF_GET_PIXEL_DATA8 ( output, output->data + pixel, &out_buf );
        //Simple Channel Swap
        out_buf->blue = in_buf->red;
        out_buf->green = in_buf->green;
        out_buf->red = in_buf->blue;
}
...
}

i get some buggy image.. what i am doing wrong here ? 

Found it finally: 

PF_GET_PIXEL_DATA8 ( in_layer, in_layer->data + pixel_idx, &in_buf );
Ref.: https://ae-plugin-sdk-guide.readthedocs.io/effect-basics/PF_EffectWorld.html#effect-basics-pf-effectworld-pf-pixelptr-accessor-macros