FFmpeg/libavcodec/h261.c

/*
 * H261 common code
 * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
 * Copyright (c) 2004 Maarten Daniels
 *
 * This file is part of Libav.
 *
 * Libav 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.
 *
 * Libav 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 Libav; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * h261codec.
 */

#include "avcodec.h"
#include "h261.h"

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

uint8_t ff_h261_rl_table_store[2][2*MAX_RUN + MAX_LEVEL + 3];

static void h261_loop_filter(uint8_t *src, int stride)
{
    int x,y,xy,yz;
    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++){
            xy = y * stride + x;
            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[7+y*stride] = (temp[7+y*8] + 2)>>2;
        for(x=1; x<7; x++){
            xy = y * stride + x;
            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 * h= (H261Context*)s;
    const int linesize  = s->linesize;
    const int 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);
}