libavcodec/jpeglsdec.c - manifest_repos/ffmpeg - Git at Google

 /*
  * 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
  * JPEG-LS decoder.
  */

 #include "avcodec.h"
 #include "get_bits.h"
 #include "golomb.h"
 #include "internal.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 id;
     int tid, wt, maxtab, i, j;

     int len = get_bits(&s->gb, 16);
     id = get_bits(&s->gb, 8);

     switch (id) {
     case 1:
         if (len < 13)
             return AVERROR_INVALIDDATA;

         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);

         if(s->avctx->debug & FF_DEBUG_PICT_INFO) {
             av_log(s->avctx, AV_LOG_DEBUG, "Coding parameters maxval:%d T1:%d T2:%d T3:%d reset:%d\n",
                    s->maxval, s->t1, s->t2, s->t3, s->reset);
         }

 //        ff_jpegls_reset_coding_parameters(s, 0);
         //FIXME quant table?
         break;
     case 2:
         s->palette_index = 0;
     case 3:
         tid= get_bits(&s->gb, 8);
         wt = get_bits(&s->gb, 8);

         if (len < 5)
             return AVERROR_INVALIDDATA;

         if (wt < 1 || wt > MAX_COMPONENTS) {
             avpriv_request_sample(s->avctx, "wt %d", wt);
             return AVERROR_PATCHWELCOME;
         }

         if (!s->maxval)
             maxtab = 255;
         else if ((5 + wt*(s->maxval+1)) < 65535)
             maxtab = s->maxval;
         else
             maxtab = 65530/wt - 1;

         if(s->avctx->debug & FF_DEBUG_PICT_INFO) {
             av_log(s->avctx, AV_LOG_DEBUG, "LSE palette %d tid:%d wt:%d maxtab:%d\n", id, tid, wt, maxtab);
         }
         if (maxtab >= 256) {
             avpriv_request_sample(s->avctx, ">8bit palette");
             return AVERROR_PATCHWELCOME;
         }
         maxtab = FFMIN(maxtab, (len - 5) / wt + s->palette_index);

         if (s->palette_index > maxtab)
             return AVERROR_INVALIDDATA;

         if ((s->avctx->pix_fmt == AV_PIX_FMT_GRAY8 || s->avctx->pix_fmt == AV_PIX_FMT_PAL8) &&
             (s->picture_ptr->format == AV_PIX_FMT_GRAY8 || s->picture_ptr->format == AV_PIX_FMT_PAL8)) {
             uint32_t *pal = (uint32_t *)s->picture_ptr->data[1];
             int shift = 0;

             if (s->avctx->bits_per_raw_sample > 0 && s->avctx->bits_per_raw_sample < 8) {
                 maxtab = FFMIN(maxtab, (1<<s->avctx->bits_per_raw_sample)-1);
                 shift = 8 - s->avctx->bits_per_raw_sample;
             }

             s->picture_ptr->format =
             s->avctx->pix_fmt = AV_PIX_FMT_PAL8;
             for (i=s->palette_index; i<=maxtab; i++) {
                 uint8_t k = i << shift;
                 pal[k] = 0;
                 for (j=0; j<wt; j++) {
                     pal[k] |= get_bits(&s->gb, 8) << (8*(wt-j-1));
                 }
             }
             s->palette_index = i;
         }
         break;
     case 4:
         avpriv_request_sample(s->avctx, "oversize image");
         return AVERROR(ENOSYS);
     default:
         av_log(s->avctx, AV_LOG_ERROR, "invalid id %d\n", id);
         return AVERROR_INVALIDDATA;
     }
     ff_dlog(s->avctx, "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;
     }

     if(FFABS(ret) > 0xFFFF)
         return -0x10000;
     /* 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 int 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;

         if (get_bits_left(&s->gb) <= 0)
             return AVERROR_INVALIDDATA;

         /* 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 0;
                 if (state->run_index[comp] < 31)
                     state->run_index[comp]++;
                 if (x + stride > w)
                     return 0;
             }
             /* decode aborted run */
             r = ff_log2_run[state->run_index[comp]];
             if (r)
                 r = get_bits_long(&s->gb, r);
             if (x + r * stride > w) {
                 r = (w - x) / stride;
             }
             for (i = 0; i < r; i++) {
                 W(dst, x, Ra);
                 x += stride;
             }

             if (x >= w) {
                 av_log(NULL, AV_LOG_ERROR, "run overflow\n");
                 av_assert0(x <= w);
                 return AVERROR_INVALIDDATA;
             }

             /* 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;
     }

     return 0;
 }

 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, ret = 0;
     int decoded_height = 0;

     zero = av_mallocz(s->picture_ptr->linesize[0]);
     if (!zero)
         return AVERROR(ENOMEM);
     last = zero;
     cur  = s->picture_ptr->data[0];

     state = av_mallocz(sizeof(JLSState));
     if (!state) {
         av_free(zero);
         return AVERROR(ENOMEM);
     }
     /* 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);

     if (shift >= 16) {
         ret = AVERROR_INVALIDDATA;
         goto end;
     }

     if (s->avctx->debug & FF_DEBUG_PICT_INFO) {
         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 (get_bits_left(&s->gb) < s->height) {
         ret = AVERROR_INVALIDDATA;
         goto end;
     }
     if (ilv == 0) { /* separate planes */
         if (s->cur_scan > s->nb_components) {
             ret = AVERROR_INVALIDDATA;
             goto end;
         }
         stride = (s->nb_components > 1) ? 3 : 1;
         off    = av_clip(s->cur_scan - 1, 0, stride - 1);
         width  = s->width * stride;
         cur   += off;
         for (i = 0; i < s->height; i++) {
             int ret;
             if (s->bits <= 8) {
                 ret = ls_decode_line(state, s, last, cur, t, width, stride, off, 8);
                 t = last[0];
             } else {
                 ret = ls_decode_line(state, s, last, cur, t, width, stride, off, 16);
                 t = *((uint16_t *)last);
             }
             if (ret < 0)
                 break;
             last = cur;
             cur += s->picture_ptr->linesize[0];

             if (s->restart_interval && !--s->restart_count) {
                 align_get_bits(&s->gb);
                 skip_bits(&s->gb, 16); /* skip RSTn */
             }
         }
         decoded_height = i;
     } else if (ilv == 1) { /* line interleaving */
         int j;
         int Rc[3] = { 0, 0, 0 };
         stride = (s->nb_components > 1) ? 3 : 1;
         memset(cur, 0, s->picture_ptr->linesize[0]);
         width = s->width * stride;
         for (i = 0; i < s->height; i++) {
             int ret;
             for (j = 0; j < stride; j++) {
                 ret = ls_decode_line(state, s, last + j, cur + j,
                                Rc[j], width, stride, j, 8);
                 if (ret < 0)
                     break;
                 Rc[j] = last[j];

                 if (s->restart_interval && !--s->restart_count) {
                     align_get_bits(&s->gb);
                     skip_bits(&s->gb, 16); /* skip RSTn */
                 }
             }
             if (ret < 0)
                 break;
             last = cur;
             cur += s->picture_ptr->linesize[0];
         }
         decoded_height = i;
     } else if (ilv == 2) { /* sample interleaving */
         avpriv_report_missing_feature(s->avctx, "Sample interleaved images");
         ret = AVERROR_PATCHWELCOME;
         goto end;
     } else { /* unknown interleaving */
         avpriv_report_missing_feature(s->avctx, "Unknown interleaved images");
         ret = AVERROR_PATCHWELCOME;
         goto end;
     }

     if (s->xfrm && s->nb_components == 3) {
         int x, w;

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

         if (s->bits <= 8) {
             uint8_t *src = s->picture_ptr->data[0];

             for (i = 0; i < s->height; i++) {
                 switch(s->xfrm) {
                 case 1:
                     for (x = off; x < w; x += 3) {
                         src[x  ] += src[x+1] + 128;
                         src[x+2] += src[x+1] + 128;
                     }
                     break;
                 case 2:
                     for (x = off; x < w; x += 3) {
                         src[x  ] += src[x+1] + 128;
                         src[x+2] += ((src[x  ] + src[x+1])>>1) + 128;
                     }
                     break;
                 case 3:
                     for (x = off; x < w; x += 3) {
                         int g = src[x+0] - ((src[x+2]+src[x+1])>>2) + 64;
                         src[x+0] = src[x+2] + g + 128;
                         src[x+2] = src[x+1] + g + 128;
                         src[x+1] = g;
                     }
                     break;
                 case 4:
                     for (x = off; x < w; x += 3) {
                         int r    = src[x+0] - ((                       359 * (src[x+2]-128) + 490) >> 8);
                         int g    = src[x+0] - (( 88 * (src[x+1]-128) - 183 * (src[x+2]-128) +  30) >> 8);
                         int b    = src[x+0] + ((454 * (src[x+1]-128)                        + 574) >> 8);
                         src[x+0] = av_clip_uint8(r);
                         src[x+1] = av_clip_uint8(g);
                         src[x+2] = av_clip_uint8(b);
                     }
                     break;
                 }
                 src += s->picture_ptr->linesize[0];
             }
         }else
             avpriv_report_missing_feature(s->avctx, "16bit xfrm");
     }

     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_ptr->data[0];

             for (i = 0; i < decoded_height; i++) {
                 for (x = off; x < w; x += stride)
                     src[x] <<= shift;
                 src += s->picture_ptr->linesize[0];
             }
         } else {
             uint16_t *src = (uint16_t *)s->picture_ptr->data[0];

             for (i = 0; i < decoded_height; i++) {
                 for (x = 0; x < w; x++)
                     src[x] <<= shift;
                 src += s->picture_ptr->linesize[0] / 2;
             }
         }
     }

 end:
     av_free(state);
     av_free(zero);

     return ret;
 }

 AVCodec ff_jpegls_decoder = {
     .name           = "jpegls",
     .long_name      = NULL_IF_CONFIG_SMALL("JPEG-LS"),
     .type           = AVMEDIA_TYPE_VIDEO,
     .id             = AV_CODEC_ID_JPEGLS,
     .priv_data_size = sizeof(MJpegDecodeContext),
     .init           = ff_mjpeg_decode_init,
     .close          = ff_mjpeg_decode_end,
     .receive_frame  = ff_mjpeg_receive_frame,
     .capabilities   = AV_CODEC_CAP_DR1,
     .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP |
                       FF_CODEC_CAP_SETS_PKT_DTS,
 };
	/*
	* 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
	* JPEG-LS decoder.
	*/

	#include "avcodec.h"
	#include "get_bits.h"
	#include "golomb.h"
	#include "internal.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 id;
	int tid, wt, maxtab, i, j;

	int len = get_bits(&s->gb, 16);
	id = get_bits(&s->gb, 8);

	switch (id) {
	case 1:
	if (len < 13)
	return AVERROR_INVALIDDATA;

	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);

	if(s->avctx->debug & FF_DEBUG_PICT_INFO) {
	av_log(s->avctx, AV_LOG_DEBUG, "Coding parameters maxval:%d T1:%d T2:%d T3:%d reset:%d\n",
	s->maxval, s->t1, s->t2, s->t3, s->reset);
	}

	// ff_jpegls_reset_coding_parameters(s, 0);
	//FIXME quant table?
	break;
	case 2:
	s->palette_index = 0;
	case 3:
	tid= get_bits(&s->gb, 8);
	wt = get_bits(&s->gb, 8);

	if (len < 5)
	return AVERROR_INVALIDDATA;

	if (wt < 1 \|\| wt > MAX_COMPONENTS) {
	avpriv_request_sample(s->avctx, "wt %d", wt);
	return AVERROR_PATCHWELCOME;
	}

	if (!s->maxval)
	maxtab = 255;
	else if ((5 + wt*(s->maxval+1)) < 65535)
	maxtab = s->maxval;
	else
	maxtab = 65530/wt - 1;

	if(s->avctx->debug & FF_DEBUG_PICT_INFO) {
	av_log(s->avctx, AV_LOG_DEBUG, "LSE palette %d tid:%d wt:%d maxtab:%d\n", id, tid, wt, maxtab);
	}
	if (maxtab >= 256) {
	avpriv_request_sample(s->avctx, ">8bit palette");
	return AVERROR_PATCHWELCOME;
	}
	maxtab = FFMIN(maxtab, (len - 5) / wt + s->palette_index);

	if (s->palette_index > maxtab)
	return AVERROR_INVALIDDATA;

	if ((s->avctx->pix_fmt == AV_PIX_FMT_GRAY8 \|\| s->avctx->pix_fmt == AV_PIX_FMT_PAL8) &&
	(s->picture_ptr->format == AV_PIX_FMT_GRAY8 \|\| s->picture_ptr->format == AV_PIX_FMT_PAL8)) {
	uint32_t pal = (uint32_t )s->picture_ptr->data[1];
	int shift = 0;

	if (s->avctx->bits_per_raw_sample > 0 && s->avctx->bits_per_raw_sample < 8) {
	maxtab = FFMIN(maxtab, (1<<s->avctx->bits_per_raw_sample)-1);
	shift = 8 - s->avctx->bits_per_raw_sample;
	}

	s->picture_ptr->format =
	s->avctx->pix_fmt = AV_PIX_FMT_PAL8;
	for (i=s->palette_index; i<=maxtab; i++) {
	uint8_t k = i << shift;
	pal[k] = 0;
	for (j=0; j<wt; j++) {
	pal[k] \|= get_bits(&s->gb, 8) << (8*(wt-j-1));
	}
	}
	s->palette_index = i;
	}
	break;
	case 4:
	avpriv_request_sample(s->avctx, "oversize image");
	return AVERROR(ENOSYS);
	default:
	av_log(s->avctx, AV_LOG_ERROR, "invalid id %d\n", id);
	return AVERROR_INVALIDDATA;
	}
	ff_dlog(s->avctx, "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 2B[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;
	}

	if(FFABS(ret) > 0xFFFF)
	return -0x10000;
	/* 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 int 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;

	if (get_bits_left(&s->gb) <= 0)
	return AVERROR_INVALIDDATA;

	/* 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 0;
	if (state->run_index[comp] < 31)
	state->run_index[comp]++;
	if (x + stride > w)
	return 0;
	}
	/* decode aborted run */
	r = ff_log2_run[state->run_index[comp]];
	if (r)
	r = get_bits_long(&s->gb, r);
	if (x + r * stride > w) {
	r = (w - x) / stride;
	}
	for (i = 0; i < r; i++) {
	W(dst, x, Ra);
	x += stride;
	}

	if (x >= w) {
	av_log(NULL, AV_LOG_ERROR, "run overflow\n");
	av_assert0(x <= w);
	return AVERROR_INVALIDDATA;
	}

	/* 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;
	}

	return 0;
	}

	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, ret = 0;
	int decoded_height = 0;

	zero = av_mallocz(s->picture_ptr->linesize[0]);
	if (!zero)
	return AVERROR(ENOMEM);
	last = zero;
	cur = s->picture_ptr->data[0];

	state = av_mallocz(sizeof(JLSState));
	if (!state) {
	av_free(zero);
	return AVERROR(ENOMEM);
	}
	/* 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);

	if (shift >= 16) {
	ret = AVERROR_INVALIDDATA;
	goto end;
	}

	if (s->avctx->debug & FF_DEBUG_PICT_INFO) {
	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 (get_bits_left(&s->gb) < s->height) {
	ret = AVERROR_INVALIDDATA;
	goto end;
	}
	if (ilv == 0) { /* separate planes */
	if (s->cur_scan > s->nb_components) {
	ret = AVERROR_INVALIDDATA;
	goto end;
	}
	stride = (s->nb_components > 1) ? 3 : 1;
	off = av_clip(s->cur_scan - 1, 0, stride - 1);
	width = s->width * stride;
	cur += off;
	for (i = 0; i < s->height; i++) {
	int ret;
	if (s->bits <= 8) {
	ret = ls_decode_line(state, s, last, cur, t, width, stride, off, 8);
	t = last[0];
	} else {
	ret = ls_decode_line(state, s, last, cur, t, width, stride, off, 16);
	t = ((uint16_t )last);
	}
	if (ret < 0)
	break;
	last = cur;
	cur += s->picture_ptr->linesize[0];

	if (s->restart_interval && !--s->restart_count) {
	align_get_bits(&s->gb);
	skip_bits(&s->gb, 16); /* skip RSTn */
	}
	}
	decoded_height = i;
	} else if (ilv == 1) { /* line interleaving */
	int j;
	int Rc[3] = { 0, 0, 0 };
	stride = (s->nb_components > 1) ? 3 : 1;
	memset(cur, 0, s->picture_ptr->linesize[0]);
	width = s->width * stride;
	for (i = 0; i < s->height; i++) {
	int ret;
	for (j = 0; j < stride; j++) {
	ret = ls_decode_line(state, s, last + j, cur + j,
	Rc[j], width, stride, j, 8);
	if (ret < 0)
	break;
	Rc[j] = last[j];

	if (s->restart_interval && !--s->restart_count) {
	align_get_bits(&s->gb);
	skip_bits(&s->gb, 16); /* skip RSTn */
	}
	}
	if (ret < 0)
	break;
	last = cur;
	cur += s->picture_ptr->linesize[0];
	}
	decoded_height = i;
	} else if (ilv == 2) { /* sample interleaving */
	avpriv_report_missing_feature(s->avctx, "Sample interleaved images");
	ret = AVERROR_PATCHWELCOME;
	goto end;
	} else { /* unknown interleaving */
	avpriv_report_missing_feature(s->avctx, "Unknown interleaved images");
	ret = AVERROR_PATCHWELCOME;
	goto end;
	}

	if (s->xfrm && s->nb_components == 3) {
	int x, w;

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

	if (s->bits <= 8) {
	uint8_t *src = s->picture_ptr->data[0];

	for (i = 0; i < s->height; i++) {
	switch(s->xfrm) {
	case 1:
	for (x = off; x < w; x += 3) {
	src[x ] += src[x+1] + 128;
	src[x+2] += src[x+1] + 128;
	}
	break;
	case 2:
	for (x = off; x < w; x += 3) {
	src[x ] += src[x+1] + 128;
	src[x+2] += ((src[x ] + src[x+1])>>1) + 128;
	}
	break;
	case 3:
	for (x = off; x < w; x += 3) {
	int g = src[x+0] - ((src[x+2]+src[x+1])>>2) + 64;
	src[x+0] = src[x+2] + g + 128;
	src[x+2] = src[x+1] + g + 128;
	src[x+1] = g;
	}
	break;
	case 4:
	for (x = off; x < w; x += 3) {
	int r = src[x+0] - (( 359 * (src[x+2]-128) + 490) >> 8);
	int g = src[x+0] - (( 88 * (src[x+1]-128) - 183 * (src[x+2]-128) + 30) >> 8);
	int b = src[x+0] + ((454 * (src[x+1]-128) + 574) >> 8);
	src[x+0] = av_clip_uint8(r);
	src[x+1] = av_clip_uint8(g);
	src[x+2] = av_clip_uint8(b);
	}
	break;
	}
	src += s->picture_ptr->linesize[0];
	}
	}else
	avpriv_report_missing_feature(s->avctx, "16bit xfrm");
	}

	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_ptr->data[0];

	for (i = 0; i < decoded_height; i++) {
	for (x = off; x < w; x += stride)
	src[x] <<= shift;
	src += s->picture_ptr->linesize[0];
	}
	} else {
	uint16_t src = (uint16_t )s->picture_ptr->data[0];

	for (i = 0; i < decoded_height; i++) {
	for (x = 0; x < w; x++)
	src[x] <<= shift;
	src += s->picture_ptr->linesize[0] / 2;
	}
	}
	}

	end:
	av_free(state);
	av_free(zero);

	return ret;
	}

	AVCodec ff_jpegls_decoder = {
	.name = "jpegls",
	.long_name = NULL_IF_CONFIG_SMALL("JPEG-LS"),
	.type = AVMEDIA_TYPE_VIDEO,
	.id = AV_CODEC_ID_JPEGLS,
	.priv_data_size = sizeof(MJpegDecodeContext),
	.init = ff_mjpeg_decode_init,
	.close = ff_mjpeg_decode_end,
	.receive_frame = ff_mjpeg_receive_frame,
	.capabilities = AV_CODEC_CAP_DR1,
	.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE \| FF_CODEC_CAP_INIT_CLEANUP \|
	FF_CODEC_CAP_SETS_PKT_DTS,
	};