PeerStreamer

/*

 * JPEG-LS decoder

 * 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 libavcodec/jpeglsdec.c

 * JPEG-LS decoder.

 */

#include "avcodec.h"

#include "get_bits.h"

#include "golomb.h"

#include "mathops.h"

#include "mjpeg.h"

#include "mjpegdec.h"

#include "jpegls.h"

#include "jpeglsdec.h"

/*

* Uncomment this to significantly speed up decoding of broken JPEG-LS

* (or test broken JPEG-LS decoder) and slow down ordinary decoding a bit.

*

* There is no Golomb code with length >= 32 bits possible, so check and

* avoid situation of 32 zeros, FFmpeg Golomb decoder is painfully slow

* on this errors.

*/

//#define JLS_BROKEN

/**

 * Decode LSE block with initialization parameters

 */

int ff_jpegls_decode_lse(MJpegDecodeContext *s)

{

    int len, id;

    /* XXX: verify len field validity */

    len = get_bits(&s->gb, 16);

    id = get_bits(&s->gb, 8);

    switch(id){

    case 1:

        s->maxval= get_bits(&s->gb, 16);

        s->t1= get_bits(&s->gb, 16);

        s->t2= get_bits(&s->gb, 16);

        s->t3= get_bits(&s->gb, 16);

        s->reset= get_bits(&s->gb, 16);

//        ff_jpegls_reset_coding_parameters(s, 0);

        //FIXME quant table?

        break;

    case 2:

    case 3:

        av_log(s->avctx, AV_LOG_ERROR, "palette not supported\n");

        return -1;

    case 4:

        av_log(s->avctx, AV_LOG_ERROR, "oversize image not supported\n");

        return -1;

    default:

        av_log(s->avctx, AV_LOG_ERROR, "invalid id %d\n", id);

        return -1;

    }

//    av_log(s->avctx, AV_LOG_DEBUG, "ID=%i, T=%i,%i,%i\n", id, s->t1, s->t2, s->t3);

    return 0;

}

/**

 * Get context-dependent Golomb code, decode it and update context

 */

static inline int ls_get_code_regular(GetBitContext *gb, JLSState *state, int Q){

    int k, ret;

    for(k = 0; (state->N[Q] << k) < state->A[Q]; k++);

#ifdef JLS_BROKEN

    if(!show_bits_long(gb, 32))return -1;

#endif

    ret = get_ur_golomb_jpegls(gb, k, state->limit, state->qbpp);

    /* decode mapped error */

    if(ret & 1)

        ret = -((ret + 1) >> 1);

    else

        ret >>= 1;

    /* for NEAR=0, k=0 and 2*B[Q] <= - N[Q] mapping is reversed */

    if(!state->near && !k && (2 * state->B[Q] <= -state->N[Q]))

        ret = -(ret + 1);

    ret= ff_jpegls_update_state_regular(state, Q, ret);

    return ret;

}

/**

 * Get Golomb code, decode it and update state for run termination

 */

static inline int ls_get_code_runterm(GetBitContext *gb, JLSState *state, int RItype, int limit_add){

    int k, ret, temp, map;

    int Q = 365 + RItype;

    temp=  state->A[Q];

    if(RItype)

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

    for(k = 0; (state->N[Q] << k) < temp; k++);

#ifdef JLS_BROKEN

    if(!show_bits_long(gb, 32))return -1;

#endif

    ret = get_ur_golomb_jpegls(gb, k, state->limit - limit_add - 1, state->qbpp);

    /* decode mapped error */

    map = 0;

    if(!k && (RItype || ret) && (2 * state->B[Q] < state->N[Q]))

        map = 1;

    ret += RItype + map;

    if(ret & 1){

        ret = map - ((ret + 1) >> 1);

        state->B[Q]++;

    } else {

        ret = ret >> 1;

    }

    /* update state */

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

    ret *= state->twonear;

    ff_jpegls_downscale_state(state, Q);

    return ret;

}

/**

 * Decode one line of image

 */

static inline void ls_decode_line(JLSState *state, MJpegDecodeContext *s, void *last, void *dst, int last2, int w, int stride, int comp, int bits){

    int i, x = 0;

    int Ra, Rb, Rc, Rd;

    int D0, D1, D2;

    while(x < w) {

        int err, pred;

        /* compute gradients */

        Ra = x ? R(dst, x - stride) : R(last, x);

        Rb = R(last, x);

        Rc = x ? R(last, x - stride) : last2;

        Rd = (x >= w - stride) ? R(last, x) : R(last, x + stride);

        D0 = Rd - Rb;

        D1 = Rb - Rc;

        D2 = Rc - Ra;

        /* run mode */

        if((FFABS(D0) <= state->near) && (FFABS(D1) <= state->near) && (FFABS(D2) <= state->near)) {

            int r;

            int RItype;

            /* decode full runs while available */

            while(get_bits1(&s->gb)) {

                int r;

                r = 1 << ff_log2_run[state->run_index[comp]];

                if(x + r * stride > w) {

                    r = (w - x) / stride;

                }

                for(i = 0; i < r; i++) {

                    W(dst, x, Ra);

                    x += stride;

                }

                /* if EOL reached, we stop decoding */

                if(r != (1 << ff_log2_run[state->run_index[comp]]))

                    return;

                if(state->run_index[comp] < 31)

                    state->run_index[comp]++;

                if(x + stride > w)

                    return;

            }

            /* decode aborted run */

            r = ff_log2_run[state->run_index[comp]];

            if(r)

                r = get_bits_long(&s->gb, r);

            for(i = 0; i < r; i++) {

                W(dst, x, Ra);

                x += stride;

            }

            /* decode run termination value */

            Rb = R(last, x);

            RItype = (FFABS(Ra - Rb) <= state->near) ? 1 : 0;

            err = ls_get_code_runterm(&s->gb, state, RItype, ff_log2_run[state->run_index[comp]]);

            if(state->run_index[comp])

                state->run_index[comp]--;

            if(state->near && RItype){

                pred = Ra + err;

            } else {

                if(Rb < Ra)

                    pred = Rb - err;

                else

                    pred = Rb + err;

            }

        } else { /* regular mode */

            int context, sign;

            context = ff_jpegls_quantize(state, D0) * 81 + ff_jpegls_quantize(state, D1) * 9 + ff_jpegls_quantize(state, D2);

            pred = mid_pred(Ra, Ra + Rb - Rc, Rb);

            if(context < 0){

                context = -context;

                sign = 1;

            }else{

                sign = 0;

            }

            if(sign){

                pred = av_clip(pred - state->C[context], 0, state->maxval);

                err = -ls_get_code_regular(&s->gb, state, context);

            } else {

                pred = av_clip(pred + state->C[context], 0, state->maxval);

                err = ls_get_code_regular(&s->gb, state, context);

            }

            /* we have to do something more for near-lossless coding */

            pred += err;

        }

        if(state->near){

            if(pred < -state->near)

                pred += state->range * state->twonear;

            else if(pred > state->maxval + state->near)

                pred -= state->range * state->twonear;

            pred = av_clip(pred, 0, state->maxval);

        }

        pred &= state->maxval;

        W(dst, x, pred);

        x += stride;

    }

}

int ff_jpegls_decode_picture(MJpegDecodeContext *s, int near, int point_transform, int ilv){

    int i, t = 0;

    uint8_t *zero, *last, *cur;

    JLSState *state;

    int off = 0, stride = 1, width, shift;

    zero = av_mallocz(s->picture.linesize[0]);

    last = zero;

    cur = s->picture.data[0];

    state = av_mallocz(sizeof(JLSState));

    /* initialize JPEG-LS state from JPEG parameters */

    state->near = near;

    state->bpp = (s->bits < 2) ? 2 : s->bits;

    state->maxval = s->maxval;

    state->T1 = s->t1;

    state->T2 = s->t2;

    state->T3 = s->t3;

    state->reset = s->reset;

    ff_jpegls_reset_coding_parameters(state, 0);

    ff_jpegls_init_state(state);

    if(s->bits <= 8)

        shift = point_transform + (8 - s->bits);

    else

        shift = point_transform + (16 - s->bits);

//    av_log(s->avctx, AV_LOG_DEBUG, "JPEG-LS params: %ix%i NEAR=%i MV=%i T(%i,%i,%i) RESET=%i, LIMIT=%i, qbpp=%i, RANGE=%i\n",s->width,s->height,state->near,state->maxval,state->T1,state->T2,state->T3,state->reset,state->limit,state->qbpp, state->range);

//    av_log(s->avctx, AV_LOG_DEBUG, "JPEG params: ILV=%i Pt=%i BPP=%i, scan = %i\n", ilv, point_transform, s->bits, s->cur_scan);

    if(ilv == 0) { /* separate planes */

        off = s->cur_scan - 1;

        stride = (s->nb_components > 1) ? 3 : 1;

        width = s->width * stride;

        cur += off;

        for(i = 0; i < s->height; i++) {

            if(s->bits <= 8){

                ls_decode_line(state, s, last, cur, t, width, stride, off,  8);

                t = last[0];

            }else{

                ls_decode_line(state, s, last, cur, t, width, stride, off, 16);

                t = *((uint16_t*)last);

            }

            last = cur;

            cur += s->picture.linesize[0];

            if (s->restart_interval && !--s->restart_count) {

                align_get_bits(&s->gb);

                skip_bits(&s->gb, 16); /* skip RSTn */

            }

        }

    } else if(ilv == 1) { /* line interleaving */

        int j;

        int Rc[3] = {0, 0, 0};

        memset(cur, 0, s->picture.linesize[0]);

        width = s->width * 3;

        for(i = 0; i < s->height; i++) {

            for(j = 0; j < 3; j++) {

                ls_decode_line(state, s, last + j, cur + j, Rc[j], width, 3, j, 8);

                Rc[j] = last[j];

                if (s->restart_interval && !--s->restart_count) {

                    align_get_bits(&s->gb);

                    skip_bits(&s->gb, 16); /* skip RSTn */

                }

            }

            last = cur;

            cur += s->picture.linesize[0];

        }

    } else if(ilv == 2) { /* sample interleaving */

        av_log(s->avctx, AV_LOG_ERROR, "Sample interleaved images are not supported.\n");

        av_free(state);

        av_free(zero);

        return -1;

    }

    if(shift){ /* we need to do point transform or normalize samples */

        int x, w;

        w = s->width * s->nb_components;

        if(s->bits <= 8){

            uint8_t *src = s->picture.data[0];

            for(i = 0; i < s->height; i++){

                for(x = off; x < w; x+= stride){

                    src[x] <<= shift;

                }

                src += s->picture.linesize[0];

            }

        }else{

            uint16_t *src = (uint16_t*) s->picture.data[0];

            for(i = 0; i < s->height; i++){

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

                    src[x] <<= shift;

                }

                src += s->picture.linesize[0]/2;

            }

        }

    }

    av_free(state);

    av_free(zero);

    return 0;

}

AVCodec jpegls_decoder = {

    "jpegls",

    CODEC_TYPE_VIDEO,

    CODEC_ID_JPEGLS,

    sizeof(MJpegDecodeContext),

    ff_mjpeg_decode_init,

    NULL,

    ff_mjpeg_decode_end,

    ff_mjpeg_decode_frame,

    CODEC_CAP_DR1,

    .long_name = NULL_IF_CONFIG_SMALL("JPEG-LS"),

};