PeerStreamer

/*

 * JPEG-LS common code

 * Copyright (c) 2003 Michael Niedermayer

 * Copyright (c) 2006 Konstantin Shishkov

 *

 * 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 jpegls.h

 * JPEG-LS common code.

 */

#ifndef FFMPEG_JPEGLS_H

#define FFMPEG_JPEGLS_H

#include "avcodec.h"

typedef struct JpeglsContext{

    AVCodecContext *avctx;

    AVFrame picture;

}JpeglsContext;

typedef struct JLSState{

    int T1, T2, T3;

    int A[367], B[367], C[365], N[367];

    int limit, reset, bpp, qbpp, maxval, range;

    int near, twonear;

    int run_index[3];

}JLSState;

extern const uint8_t ff_log2_run[32];

/**

 * Calculate initial JPEG-LS parameters

 */

void ff_jpegls_init_state(JLSState *state);

/**

 * Calculate quantized gradient value, used for context determination

 */

static inline int ff_jpegls_quantize(JLSState *s, int v){ //FIXME optimize

    if(v==0) return 0;

    if(v < 0){

        if(v <= -s->T3) return -4;

        if(v <= -s->T2) return -3;

        if(v <= -s->T1) return -2;

        if(v <  -s->near) return -1;

        return 0;

    }else{

        if(v <= s->near) return 0;

        if(v <  s->T1) return 1;

        if(v <  s->T2) return 2;

        if(v <  s->T3) return 3;

        return 4;

    }

}

/**

 * Calculate JPEG-LS codec values

 */

void ff_jpegls_reset_coding_parameters(JLSState *s, int reset_all);

static inline void ff_jpegls_downscale_state(JLSState *state, int Q){

    if(state->N[Q] == state->reset){

        state->A[Q] >>=1;

        state->B[Q] >>=1;

        state->N[Q] >>=1;

    }

    state->N[Q]++;

}

static inline int ff_jpegls_update_state_regular(JLSState *state, int Q, int err){

    state->A[Q] += FFABS(err);

    err *= state->twonear;

    state->B[Q] += err;

    ff_jpegls_downscale_state(state, Q);

    if(state->B[Q] <= -state->N[Q]) {

        state->B[Q]= FFMAX(state->B[Q] + state->N[Q], 1-state->N[Q]);

        if(state->C[Q] > -128)

            state->C[Q]--;

    }else if(state->B[Q] > 0){

        state->B[Q]= FFMIN(state->B[Q] - state->N[Q], 0);

        if(state->C[Q] < 127)

            state->C[Q]++;

    }

    return err;

}

#define R(a, i   ) (bits == 8 ?  ((uint8_t*)(a))[i]    :  ((uint16_t*)(a))[i]  )

#define W(a, i, v) (bits == 8 ? (((uint8_t*)(a))[i]=v) : (((uint16_t*)(a))[i]=v))

#endif /* FFMPEG_JPEGLS_H */