PeerStreamer

/*

 * JPEG-LS encoder

 * 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 jpeglsenc.c

 * JPEG-LS encoder.

 */

#include "avcodec.h"

#include "bitstream.h"

#include "golomb.h"

#include "dsputil.h"

#include "mjpeg.h"

#include "jpegls.h"

/**

 * Encode error from regular symbol

 */

static inline void ls_encode_regular(JLSState *state, PutBitContext *pb, int Q, int err){

    int k;

    int val;

    int map;

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

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

    if(err < 0)

        err += state->range;

    if(err >= ((state->range + 1) >> 1)) {

        err -= state->range;

        val = 2 * FFABS(err) - 1 - map;

    } else

        val = 2 * err + map;

    set_ur_golomb_jpegls(pb, val, k, state->limit, state->qbpp);

    ff_jpegls_update_state_regular(state, Q, err);

}

/**

 * Encode error from run termination

 */

static inline void ls_encode_runterm(JLSState *state, PutBitContext *pb, int RItype, int err, int limit_add){

    int k;

    int val, map;

    int Q = 365 + RItype;

    int temp;

    temp = state->A[Q];

    if(RItype)

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

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

    map = 0;

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

        map = 1;

    if(err < 0)

        val = - (2 * err) - 1 - RItype + map;

    else

        val = 2 * err - RItype - map;

    set_ur_golomb_jpegls(pb, val, k, state->limit - limit_add - 1, state->qbpp);

    if(err < 0)

        state->B[Q]++;

    state->A[Q] += (val + 1 - RItype) >> 1;

    ff_jpegls_downscale_state(state, Q);

}

/**

 * Encode run value as specified by JPEG-LS standard

 */

static inline void ls_encode_run(JLSState *state, PutBitContext *pb, int run, int comp, int trail){

    while(run >= (1 << ff_log2_run[state->run_index[comp]])){

        put_bits(pb, 1, 1);

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

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

            state->run_index[comp]++;

    }

    /* if hit EOL, encode another full run, else encode aborted run */

    if(!trail && run) {

        put_bits(pb, 1, 1);

    }else if(trail){

        put_bits(pb, 1, 0);

        if(ff_log2_run[state->run_index[comp]])

            put_bits(pb, ff_log2_run[state->run_index[comp]], run);

    }

}

/**

 * Encode one line of image

 */

static inline void ls_encode_line(JLSState *state, PutBitContext *pb, void *last, void *cur, int last2, int w, int stride, int comp, int bits){

    int x = 0;

    int Ra, Rb, Rc, Rd;

    int D0, D1, D2;

    while(x < w) {

        int err, pred, sign;

        /* compute gradients */

        Ra = x ? R(cur, 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 RUNval, RItype, run;

            run = 0;

            RUNval = Ra;

            while(x < w && (FFABS(R(cur, x) - RUNval) <= state->near)){

                run++;

                W(cur, x, Ra);

                x += stride;

            }

            ls_encode_run(state, pb, run, comp, x < w);

            if(x >= w)

                return;

            Rb = R(last, x);

            RItype = (FFABS(Ra - Rb) <= state->near);

            pred = RItype ? Ra : Rb;

            err = R(cur, x) - pred;

            if(!RItype && Ra > Rb)

                err = -err;

            if(state->near){

                if(err > 0)

                    err = (state->near + err) / state->twonear;

                else

                    err = -(state->near - err) / state->twonear;

                if(RItype || (Rb >= Ra))

                    Ra = av_clip(pred + err * state->twonear, 0, state->maxval);

                else

                    Ra = av_clip(pred - err * state->twonear, 0, state->maxval);

                W(cur, x, Ra);

            }

            if(err < 0)

                err += state->range;

            if(err >= ((state->range + 1) >> 1))

                err -= state->range;

            ls_encode_runterm(state, pb, RItype, err, ff_log2_run[state->run_index[comp]]);

            if(state->run_index[comp] > 0)

                state->run_index[comp]--;

        } else { /* regular mode */

            int context;

            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;

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

                err = pred - R(cur, x);

            }else{

                sign = 0;

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

                err = R(cur, x) - pred;

            }

            if(state->near){

                if(err > 0)

                    err = (state->near + err) / state->twonear;

                else

                    err = -(state->near - err) / state->twonear;

                if(!sign)

                    Ra = av_clip(pred + err * state->twonear, 0, state->maxval);

                else

                    Ra = av_clip(pred - err * state->twonear, 0, state->maxval);

                W(cur, x, Ra);

            }

            ls_encode_regular(state, pb, context, err);

        }

        x += stride;

    }

}

static void ls_store_lse(JLSState *state, PutBitContext *pb){

    /* Test if we have default params and don't need to store LSE */

    JLSState state2;

    memset(&state2, 0, sizeof(JLSState));

    state2.bpp = state->bpp;

    state2.near = state->near;

    ff_jpegls_reset_coding_parameters(&state2, 1);

    if(state->T1 == state2.T1 && state->T2 == state2.T2 && state->T3 == state2.T3 && state->reset == state2.reset)

        return;

    /* store LSE type 1 */

    put_marker(pb, LSE);

    put_bits(pb, 16, 13);

    put_bits(pb, 8,   1);

    put_bits(pb, 16, state->maxval);

    put_bits(pb, 16, state->T1);

    put_bits(pb, 16, state->T2);

    put_bits(pb, 16, state->T3);

    put_bits(pb, 16, state->reset);

}

static int encode_picture_ls(AVCodecContext *avctx, unsigned char *buf, int buf_size, void *data){

    JpeglsContext * const s = avctx->priv_data;

    AVFrame *pict = data;

    AVFrame * const p= (AVFrame*)&s->picture;

    const int near = avctx->prediction_method;

    PutBitContext pb, pb2;

    GetBitContext gb;

    uint8_t *buf2, *zero, *cur, *last;

    JLSState *state;

    int i, size;

    int comps;

    buf2 = av_malloc(buf_size);

    init_put_bits(&pb, buf, buf_size);

    init_put_bits(&pb2, buf2, buf_size);

    *p = *pict;

    p->pict_type= FF_I_TYPE;

    p->key_frame= 1;

    if(avctx->pix_fmt == PIX_FMT_GRAY8 || avctx->pix_fmt == PIX_FMT_GRAY16)

        comps = 1;

    else

        comps = 3;

    /* write our own JPEG header, can't use mjpeg_picture_header */

    put_marker(&pb, SOI);

    put_marker(&pb, SOF48);

    put_bits(&pb, 16, 8 + comps * 3); // header size depends on components

    put_bits(&pb,  8, (avctx->pix_fmt == PIX_FMT_GRAY16) ? 16 : 8); // bpp

    put_bits(&pb, 16, avctx->height);

    put_bits(&pb, 16, avctx->width);

    put_bits(&pb,  8, comps);         // components

    for(i = 1; i <= comps; i++) {

        put_bits(&pb,  8, i);    // component ID

        put_bits(&pb,  8, 0x11); // subsampling: none

        put_bits(&pb,  8, 0);    // Tiq, used by JPEG-LS ext

    }

    put_marker(&pb, SOS);

    put_bits(&pb, 16, 6 + comps * 2);

    put_bits(&pb,  8, comps);

    for(i = 1; i <= comps; i++) {

        put_bits(&pb,  8, i);  // component ID

        put_bits(&pb,  8, 0);  // mapping index: none

    }

    put_bits(&pb,  8, near);

    put_bits(&pb,  8, (comps > 1) ? 1 : 0); // interleaving: 0 - plane, 1 - line

    put_bits(&pb,  8, 0); // point transform: none

    state = av_mallocz(sizeof(JLSState));

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

    state->near = near;

    state->bpp = (avctx->pix_fmt == PIX_FMT_GRAY16) ? 16 : 8;

    ff_jpegls_reset_coding_parameters(state, 0);

    ff_jpegls_init_state(state);

    ls_store_lse(state, &pb);

    zero = av_mallocz(p->linesize[0]);

    last = zero;

    cur = p->data[0];

    if(avctx->pix_fmt == PIX_FMT_GRAY8){

        int t = 0;

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

            ls_encode_line(state, &pb2, last, cur, t, avctx->width, 1, 0,  8);

            t = last[0];

            last = cur;

            cur += p->linesize[0];

        }

    }else if(avctx->pix_fmt == PIX_FMT_GRAY16){

        int t = 0;

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

            ls_encode_line(state, &pb2, last, cur, t, avctx->width, 1, 0, 16);

            t = *((uint16_t*)last);

            last = cur;

            cur += p->linesize[0];

        }

    }else if(avctx->pix_fmt == PIX_FMT_RGB24){

        int j, width;

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

        width = avctx->width * 3;

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

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

                ls_encode_line(state, &pb2, last + j, cur + j, Rc[j], width, 3, j, 8);

                Rc[j] = last[j];

            }

            last = cur;

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

        }

    }else if(avctx->pix_fmt == PIX_FMT_BGR24){

        int j, width;

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

        width = avctx->width * 3;

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

            for(j = 2; j >= 0; j--) {

                ls_encode_line(state, &pb2, last + j, cur + j, Rc[j], width, 3, j, 8);

                Rc[j] = last[j];

            }

            last = cur;

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

        }

    }

    av_free(zero);

    av_free(state);

    // the specification says that after doing 0xff escaping unused bits in the

    // last byte must be set to 0, so just append 7 "optional" zero-bits to

    // avoid special-casing.

    put_bits(&pb2, 7, 0);

    size = put_bits_count(&pb2);

    flush_put_bits(&pb2);

    /* do escape coding */

    init_get_bits(&gb, buf2, size);

    size -= 7;

    while(get_bits_count(&gb) < size){

        int v;

        v = get_bits(&gb, 8);

        put_bits(&pb, 8, v);

        if(v == 0xFF){

            v = get_bits(&gb, 7);

            put_bits(&pb, 8, v);

        }

    }

    align_put_bits(&pb);

    av_free(buf2);

    /* End of image */

    put_marker(&pb, EOI);

    flush_put_bits(&pb);

    emms_c();

    return put_bits_count(&pb) >> 3;

}

static int encode_init_ls(AVCodecContext *ctx) {

    JpeglsContext *c = (JpeglsContext*)ctx->priv_data;

    c->avctx = ctx;

    ctx->coded_frame = &c->picture;

    if(ctx->pix_fmt != PIX_FMT_GRAY8 && ctx->pix_fmt != PIX_FMT_GRAY16 && ctx->pix_fmt != PIX_FMT_RGB24 && ctx->pix_fmt != PIX_FMT_BGR24){

        av_log(ctx, AV_LOG_ERROR, "Only grayscale and RGB24/BGR24 images are supported\n");

        return -1;

    }

    return 0;

}

AVCodec jpegls_encoder = { //FIXME avoid MPV_* lossless JPEG should not need them

    "jpegls",

    CODEC_TYPE_VIDEO,

    CODEC_ID_JPEGLS,

    sizeof(JpeglsContext),

    encode_init_ls,

    encode_picture_ls,

    NULL,

    .pix_fmts= (enum PixelFormat[]){PIX_FMT_BGR24, PIX_FMT_RGB24, PIX_FMT_GRAY8, PIX_FMT_GRAY16, -1},

};