/*

 * H.261 common code

 * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>

 * Copyright (c) 2004 Maarten Daniels

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * FFmpeg is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with FFmpeg; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

/**

 * @file

 * H.261 codec

 */

#include "h261.h"

#include "mpegvideo.h"

#define IS_FIL(a)    ((a) & MB_TYPE_H261_FIL)

static void h261_loop_filter(uint8_t *src, ptrdiff_t stride)

{

    int x, y;

    int temp[64];

    for (x = 0; x < 8; x++) {

        temp[x]         = 4 * src[x];

        temp[x + 7 * 8] = 4 * src[x + 7 * stride];

    }

    for (y = 1; y < 7; y++) {

        for (x = 0; x < 8; x++) {

            ptrdiff_t xy = y * stride + x;

            ptrdiff_t yz = y * 8      + x;

            temp[yz] = src[xy - stride] + 2 * src[xy] + src[xy + stride];

        }

    }

    for (y = 0; y < 8; y++) {

        src[y * stride]     = (temp[y * 8]     + 2) >> 2;

        src[y * stride + 7] = (temp[y * 8 + 7] + 2) >> 2;

        for (x = 1; x < 7; x++) {

            ptrdiff_t xy = y * stride + x;

            ptrdiff_t yz = y * 8      + x;

            src[xy] = (temp[yz - 1] + 2 * temp[yz] + temp[yz + 1] + 8) >> 4;

        }

    }

}

void ff_h261_loop_filter(MpegEncContext *s)

{

    H261Context *const h = s->private_ctx;

    const ptrdiff_t linesize   = s->linesize;

    const ptrdiff_t uvlinesize = s->uvlinesize;

    uint8_t *dest_y      = s->dest[0];

    uint8_t *dest_cb     = s->dest[1];

    uint8_t *dest_cr     = s->dest[2];

    if (!(IS_FIL(h->mtype)))

        return;

    h261_loop_filter(dest_y,                    linesize);

    h261_loop_filter(dest_y + 8,                linesize);

    h261_loop_filter(dest_y + 8 * linesize,     linesize);

    h261_loop_filter(dest_y + 8 * linesize + 8, linesize);

    h261_loop_filter(dest_cb, uvlinesize);

    h261_loop_filter(dest_cr, uvlinesize);

}