ffmpeg/libavcodec/mqc.c

/*
 * MQ-coder encoder and decoder common functions
 * Copyright (c) 2007 Kamil Nowosad
 *
 * 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
 */

/**
 * MQ-coder common (decoder/encoder) functions
 * @file
 * @author Kamil Nowosad
 */

#include <string.h>
#include <stdint.h>

#include "mqc.h"

/* MQ coder context state structure */
typedef struct MqcCxState {
    uint16_t qe;
    uint8_t  nmps;
    uint8_t  nlps;
    uint8_t  sw;
} MqcCxState;

static const MqcCxState cx_states[47] = {
    { 0x5601,  1,  1, 1 },
    { 0x3401,  2,  6, 0 },
    { 0x1801,  3,  9, 0 },
    { 0x0AC1,  4, 12, 0 },
    { 0x0521,  5, 29, 0 },
    { 0x0221, 38, 33, 0 },
    { 0x5601,  7,  6, 1 },
    { 0x5401,  8, 14, 0 },
    { 0x4801,  9, 14, 0 },
    { 0x3801, 10, 14, 0 },
    { 0x3001, 11, 17, 0 },
    { 0x2401, 12, 18, 0 },
    { 0x1C01, 13, 20, 0 },
    { 0x1601, 29, 21, 0 },
    { 0x5601, 15, 14, 1 },
    { 0x5401, 16, 14, 0 },
    { 0x5101, 17, 15, 0 },
    { 0x4801, 18, 16, 0 },
    { 0x3801, 19, 17, 0 },
    { 0x3401, 20, 18, 0 },
    { 0x3001, 21, 19, 0 },
    { 0x2801, 22, 19, 0 },
    { 0x2401, 23, 20, 0 },
    { 0x2201, 24, 21, 0 },
    { 0x1C01, 25, 22, 0 },
    { 0x1801, 26, 23, 0 },
    { 0x1601, 27, 24, 0 },
    { 0x1401, 28, 25, 0 },
    { 0x1201, 29, 26, 0 },
    { 0x1101, 30, 27, 0 },
    { 0x0AC1, 31, 28, 0 },
    { 0x09C1, 32, 29, 0 },
    { 0x08A1, 33, 30, 0 },
    { 0x0521, 34, 31, 0 },
    { 0x0441, 35, 32, 0 },
    { 0x02A1, 36, 33, 0 },
    { 0x0221, 37, 34, 0 },
    { 0x0141, 38, 35, 0 },
    { 0x0111, 39, 36, 0 },
    { 0x0085, 40, 37, 0 },
    { 0x0049, 41, 38, 0 },
    { 0x0025, 42, 39, 0 },
    { 0x0015, 43, 40, 0 },
    { 0x0009, 44, 41, 0 },
    { 0x0005, 45, 42, 0 },
    { 0x0001, 45, 43, 0 },
    { 0x5601, 46, 46, 0 }
};

uint16_t ff_mqc_qe [2 * 47];
uint8_t ff_mqc_nlps[2 * 47];
uint8_t ff_mqc_nmps[2 * 47];

void ff_mqc_init_context_tables(void)
{
    int i;
    for (i = 0; i < 47; i++) {
        ff_mqc_qe[2 * i]     =
        ff_mqc_qe[2 * i + 1] = cx_states[i].qe;

        ff_mqc_nlps[2 * i]     = 2 * cx_states[i].nlps + cx_states[i].sw;
        ff_mqc_nlps[2 * i + 1] = 2 * cx_states[i].nlps + 1 - cx_states[i].sw;
        ff_mqc_nmps[2 * i]     = 2 * cx_states[i].nmps;
        ff_mqc_nmps[2 * i + 1] = 2 * cx_states[i].nmps + 1;
    }
}

void ff_mqc_init_contexts(MqcState *mqc)
{
    memset(mqc->cx_states, 0, sizeof(mqc->cx_states));
    mqc->cx_states[MQC_CX_UNI] = 2 * 46;
    mqc->cx_states[MQC_CX_RL]  = 2 * 3;
    mqc->cx_states[0]          = 2 * 4;
}