/*

  * DVB subtitle decoding

  * Copyright (c) 2005 Ian Caulfield

  *

  * 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

  */

 #include "avcodec.h"

 #include "get_bits.h"

 #include "bytestream.h"

 #include "internal.h"

 #include "libavutil/colorspace.h"

 #include "libavutil/imgutils.h"

 #include "libavutil/opt.h"

 
 #define DVBSUB_PAGE_SEGMENT     0x10
 #define DVBSUB_REGION_SEGMENT   0x11
 #define DVBSUB_CLUT_SEGMENT     0x12
 #define DVBSUB_OBJECT_SEGMENT   0x13

 #define DVBSUB_DISPLAYDEFINITION_SEGMENT 0x14

 #define DVBSUB_DISPLAY_SEGMENT  0x80
 

 #define cm (ff_crop_tab + MAX_NEG_CROP)

 #define RGBA(r,g,b,a) (((unsigned)(a) << 24) | ((r) << 16) | ((g) << 8) | (b))

 
 typedef struct DVBSubCLUT {
     int id;

     int version;

 
     uint32_t clut4[4];
     uint32_t clut16[16];
     uint32_t clut256[256];

     struct DVBSubCLUT *next;
 } DVBSubCLUT;
 
 static DVBSubCLUT default_clut;
 
 typedef struct DVBSubObjectDisplay {
     int object_id;
     int region_id;
 
     int x_pos;
     int y_pos;
 

     int fgcolor;
     int bgcolor;

     struct DVBSubObjectDisplay *region_list_next;

     struct DVBSubObjectDisplay *object_list_next;

 } DVBSubObjectDisplay;
 
 typedef struct DVBSubObject {
     int id;

     int version;

 
     int type;

 
     DVBSubObjectDisplay *display_list;
 

     struct DVBSubObject *next;
 } DVBSubObject;
 
 typedef struct DVBSubRegionDisplay {
     int region_id;
 
     int x_pos;
     int y_pos;
 
     struct DVBSubRegionDisplay *next;
 } DVBSubRegionDisplay;
 
 typedef struct DVBSubRegion {
     int id;

     int version;

 
     int width;
     int height;
     int depth;

     int clut;

     int bgcolor;

     uint8_t *pbuf;
     int buf_size;

     int dirty;

 
     DVBSubObjectDisplay *display_list;

     struct DVBSubRegion *next;
 } DVBSubRegion;
 

 typedef struct DVBSubDisplayDefinition {
     int version;
 
     int x;
     int y;
     int width;
     int height;
 } DVBSubDisplayDefinition;
 

 typedef struct DVBSubContext {

     AVClass *class;

     int composition_id;
     int ancillary_id;
 

     int version;

     int time_out;

     int compute_edt; /**< if 1 end display time calculated using pts
                           if 0 (Default) calculated using time out */

     int compute_clut;

     int substream;

     int64_t prev_start;

     DVBSubRegion *region_list;
     DVBSubCLUT   *clut_list;
     DVBSubObject *object_list;

     DVBSubRegionDisplay *display_list;

     DVBSubDisplayDefinition *display_definition;

 } DVBSubContext;
 
 
 static DVBSubObject* get_object(DVBSubContext *ctx, int object_id)
 {
     DVBSubObject *ptr = ctx->object_list;
 

     while (ptr && ptr->id != object_id) {

         ptr = ptr->next;
     }

     return ptr;
 }
 
 static DVBSubCLUT* get_clut(DVBSubContext *ctx, int clut_id)
 {
     DVBSubCLUT *ptr = ctx->clut_list;
 

     while (ptr && ptr->id != clut_id) {

         ptr = ptr->next;
     }

     return ptr;
 }
 
 static DVBSubRegion* get_region(DVBSubContext *ctx, int region_id)
 {
     DVBSubRegion *ptr = ctx->region_list;
 

     while (ptr && ptr->id != region_id) {

         ptr = ptr->next;
     }

     return ptr;
 }
 
 static void delete_region_display_list(DVBSubContext *ctx, DVBSubRegion *region)
 {
     DVBSubObject *object, *obj2, **obj2_ptr;
     DVBSubObjectDisplay *display, *obj_disp, **obj_disp_ptr;
 

     while (region->display_list) {

         display = region->display_list;

         object = get_object(ctx, display->object_id);

         if (object) {

             obj_disp_ptr = &object->display_list;

             obj_disp = *obj_disp_ptr;

             while (obj_disp && obj_disp != display) {

                 obj_disp_ptr = &obj_disp->object_list_next;

                 obj_disp = *obj_disp_ptr;

             }

             if (obj_disp) {
                 *obj_disp_ptr = obj_disp->object_list_next;

                 if (!object->display_list) {

                     obj2_ptr = &ctx->object_list;

                     obj2 = *obj2_ptr;

                     while (obj2 != object) {

                         av_assert0(obj2);

                         obj2_ptr = &obj2->next;

                         obj2 = *obj2_ptr;

                     }

                     *obj2_ptr = obj2->next;

                     av_freep(&obj2);

                 }
             }
         }

         region->display_list = display->region_list_next;

         av_freep(&display);

     }

 }
 

 static void delete_cluts(DVBSubContext *ctx)

 {

     while (ctx->clut_list) {

         DVBSubCLUT *clut = ctx->clut_list;

 
         ctx->clut_list = clut->next;
 

         av_freep(&clut);

     }

 }

 static void delete_objects(DVBSubContext *ctx)
 {
     while (ctx->object_list) {

         DVBSubObject *object = ctx->object_list;

 
         ctx->object_list = object->next;
 

         av_freep(&object);

     }
 }
 
 static void delete_regions(DVBSubContext *ctx)
 {
     while (ctx->region_list) {

         DVBSubRegion *region = ctx->region_list;

 
         ctx->region_list = region->next;
 
         delete_region_display_list(ctx, region);
 

         av_freep(&region->pbuf);
         av_freep(&region);

     }

 }
 

 static av_cold int dvbsub_init_decoder(AVCodecContext *avctx)

 {
     int i, r, g, b, a = 0;

     DVBSubContext *ctx = avctx->priv_data;

     if (ctx->substream < 0) {
         ctx->composition_id = -1;
         ctx->ancillary_id   = -1;
     } else if (!avctx->extradata || (avctx->extradata_size < 4) || ((avctx->extradata_size % 5 != 0) && (avctx->extradata_size != 4))) {

         av_log(avctx, AV_LOG_WARNING, "Invalid DVB subtitles stream extradata!\n");

         ctx->composition_id = -1;
         ctx->ancillary_id   = -1;
     } else {

         if (avctx->extradata_size > 5*ctx->substream + 2) {
             ctx->composition_id = AV_RB16(avctx->extradata + 5*ctx->substream);
             ctx->ancillary_id   = AV_RB16(avctx->extradata + 5*ctx->substream + 2);
         } else {
             av_log(avctx, AV_LOG_WARNING, "Selected DVB subtitles sub-stream %d is not available\n", ctx->substream);
             ctx->composition_id = AV_RB16(avctx->extradata);
             ctx->ancillary_id   = AV_RB16(avctx->extradata + 2);

         }

     }

     ctx->version = -1;

     ctx->prev_start = AV_NOPTS_VALUE;

     default_clut.id = -1;
     default_clut.next = NULL;
 
     default_clut.clut4[0] = RGBA(  0,   0,   0,   0);
     default_clut.clut4[1] = RGBA(255, 255, 255, 255);
     default_clut.clut4[2] = RGBA(  0,   0,   0, 255);
     default_clut.clut4[3] = RGBA(127, 127, 127, 255);
 
     default_clut.clut16[0] = RGBA(  0,   0,   0,   0);
     for (i = 1; i < 16; i++) {
         if (i < 8) {
             r = (i & 1) ? 255 : 0;
             g = (i & 2) ? 255 : 0;
             b = (i & 4) ? 255 : 0;
         } else {
             r = (i & 1) ? 127 : 0;
             g = (i & 2) ? 127 : 0;
             b = (i & 4) ? 127 : 0;

         }

         default_clut.clut16[i] = RGBA(r, g, b, 255);
     }
 
     default_clut.clut256[0] = RGBA(  0,   0,   0,   0);
     for (i = 1; i < 256; i++) {
         if (i < 8) {
             r = (i & 1) ? 255 : 0;
             g = (i & 2) ? 255 : 0;
             b = (i & 4) ? 255 : 0;
             a = 63;
         } else {
             switch (i & 0x88) {
             case 0x00:
                 r = ((i & 1) ? 85 : 0) + ((i & 0x10) ? 170 : 0);
                 g = ((i & 2) ? 85 : 0) + ((i & 0x20) ? 170 : 0);
                 b = ((i & 4) ? 85 : 0) + ((i & 0x40) ? 170 : 0);
                 a = 255;
                 break;
             case 0x08:
                 r = ((i & 1) ? 85 : 0) + ((i & 0x10) ? 170 : 0);
                 g = ((i & 2) ? 85 : 0) + ((i & 0x20) ? 170 : 0);
                 b = ((i & 4) ? 85 : 0) + ((i & 0x40) ? 170 : 0);
                 a = 127;
                 break;
             case 0x80:
                 r = 127 + ((i & 1) ? 43 : 0) + ((i & 0x10) ? 85 : 0);
                 g = 127 + ((i & 2) ? 43 : 0) + ((i & 0x20) ? 85 : 0);
                 b = 127 + ((i & 4) ? 43 : 0) + ((i & 0x40) ? 85 : 0);
                 a = 255;
                 break;
             case 0x88:
                 r = ((i & 1) ? 43 : 0) + ((i & 0x10) ? 85 : 0);
                 g = ((i & 2) ? 43 : 0) + ((i & 0x20) ? 85 : 0);
                 b = ((i & 4) ? 43 : 0) + ((i & 0x40) ? 85 : 0);
                 a = 255;
                 break;
             }

         }

         default_clut.clut256[i] = RGBA(r, g, b, a);
     }
 
     return 0;
 }
 

 static av_cold int dvbsub_close_decoder(AVCodecContext *avctx)

 {

     DVBSubContext *ctx = avctx->priv_data;

     DVBSubRegionDisplay *display;
 

     delete_regions(ctx);
 
     delete_objects(ctx);
 
     delete_cluts(ctx);
 
     av_freep(&ctx->display_definition);

     while (ctx->display_list) {

         display = ctx->display_list;
         ctx->display_list = display->next;

         av_freep(&display);

     }
 
     return 0;
 }
 

 static int dvbsub_read_2bit_string(AVCodecContext *avctx,
                                    uint8_t *destbuf, int dbuf_len,

                                    const uint8_t **srcbuf, int buf_size,

                                    int non_mod, uint8_t *map_table, int x_pos)

 {
     GetBitContext gb;

     int bits;
     int run_length;

     int pixels_read = x_pos;

     init_get_bits(&gb, *srcbuf, buf_size << 3);

     destbuf += x_pos;
 

     while (get_bits_count(&gb) < buf_size << 3 && pixels_read < dbuf_len) {

         bits = get_bits(&gb, 2);
 

         if (bits) {

             if (non_mod != 1 || bits != 1) {

                 if (map_table)

                     *destbuf++ = map_table[bits];
                 else
                     *destbuf++ = bits;
             }
             pixels_read++;
         } else {

             bits = get_bits1(&gb);

             if (bits == 1) {
                 run_length = get_bits(&gb, 3) + 3;
                 bits = get_bits(&gb, 2);

                 if (non_mod == 1 && bits == 1)
                     pixels_read += run_length;
                 else {

                     if (map_table)

                         bits = map_table[bits];
                     while (run_length-- > 0 && pixels_read < dbuf_len) {
                         *destbuf++ = bits;
                         pixels_read++;
                     }
                 }
             } else {

                 bits = get_bits1(&gb);

                 if (bits == 0) {
                     bits = get_bits(&gb, 2);
                     if (bits == 2) {
                         run_length = get_bits(&gb, 4) + 12;
                         bits = get_bits(&gb, 2);
 
                         if (non_mod == 1 && bits == 1)
                             pixels_read += run_length;
                         else {

                             if (map_table)

                                 bits = map_table[bits];
                             while (run_length-- > 0 && pixels_read < dbuf_len) {
                                 *destbuf++ = bits;
                                 pixels_read++;
                             }
                         }
                     } else if (bits == 3) {
                         run_length = get_bits(&gb, 8) + 29;
                         bits = get_bits(&gb, 2);
 
                         if (non_mod == 1 && bits == 1)
                             pixels_read += run_length;
                         else {

                             if (map_table)

                                 bits = map_table[bits];
                             while (run_length-- > 0 && pixels_read < dbuf_len) {
                                 *destbuf++ = bits;
                                 pixels_read++;
                             }
                         }
                     } else if (bits == 1) {

                         if (map_table)

                             bits = map_table[0];
                         else
                             bits = 0;

                         run_length = 2;
                         while (run_length-- > 0 && pixels_read < dbuf_len) {

                             *destbuf++ = bits;

                             pixels_read++;

                         }
                     } else {
                         (*srcbuf) += (get_bits_count(&gb) + 7) >> 3;
                         return pixels_read;
                     }
                 } else {

                     if (map_table)

                         bits = map_table[0];
                     else
                         bits = 0;
                     *destbuf++ = bits;
                     pixels_read++;
                 }
             }
         }
     }

     if (get_bits(&gb, 6))

         av_log(avctx, AV_LOG_ERROR, "line overflow\n");

 
     (*srcbuf) += (get_bits_count(&gb) + 7) >> 3;
 
     return pixels_read;
 }

 static int dvbsub_read_4bit_string(AVCodecContext *avctx, uint8_t *destbuf, int dbuf_len,

                                    const uint8_t **srcbuf, int buf_size,

                                    int non_mod, uint8_t *map_table, int x_pos)

 {
     GetBitContext gb;

     int bits;
     int run_length;

     int pixels_read = x_pos;

     init_get_bits(&gb, *srcbuf, buf_size << 3);

     destbuf += x_pos;
 

     while (get_bits_count(&gb) < buf_size << 3 && pixels_read < dbuf_len) {

         bits = get_bits(&gb, 4);
 

         if (bits) {

             if (non_mod != 1 || bits != 1) {

                 if (map_table)

                     *destbuf++ = map_table[bits];
                 else
                     *destbuf++ = bits;
             }
             pixels_read++;
         } else {

             bits = get_bits1(&gb);

             if (bits == 0) {
                 run_length = get_bits(&gb, 3);

                 if (run_length == 0) {
                     (*srcbuf) += (get_bits_count(&gb) + 7) >> 3;
                     return pixels_read;
                 }

                 run_length += 2;

                 if (map_table)

                     bits = map_table[0];
                 else
                     bits = 0;

                 while (run_length-- > 0 && pixels_read < dbuf_len) {
                     *destbuf++ = bits;
                     pixels_read++;
                 }
             } else {

                 bits = get_bits1(&gb);

                 if (bits == 0) {
                     run_length = get_bits(&gb, 2) + 4;
                     bits = get_bits(&gb, 4);
 
                     if (non_mod == 1 && bits == 1)
                         pixels_read += run_length;
                     else {

                         if (map_table)

                             bits = map_table[bits];
                         while (run_length-- > 0 && pixels_read < dbuf_len) {
                             *destbuf++ = bits;
                             pixels_read++;
                         }
                     }
                 } else {
                     bits = get_bits(&gb, 2);
                     if (bits == 2) {
                         run_length = get_bits(&gb, 4) + 9;
                         bits = get_bits(&gb, 4);

                         if (non_mod == 1 && bits == 1)
                             pixels_read += run_length;
                         else {

                             if (map_table)

                                 bits = map_table[bits];
                             while (run_length-- > 0 && pixels_read < dbuf_len) {
                                 *destbuf++ = bits;
                                 pixels_read++;
                             }
                         }
                     } else if (bits == 3) {
                         run_length = get_bits(&gb, 8) + 25;
                         bits = get_bits(&gb, 4);
 
                         if (non_mod == 1 && bits == 1)
                             pixels_read += run_length;
                         else {

                             if (map_table)

                                 bits = map_table[bits];
                             while (run_length-- > 0 && pixels_read < dbuf_len) {
                                 *destbuf++ = bits;
                                 pixels_read++;
                             }
                         }
                     } else if (bits == 1) {

                         if (map_table)

                             bits = map_table[0];
                         else
                             bits = 0;

                         run_length = 2;
                         while (run_length-- > 0 && pixels_read < dbuf_len) {

                             *destbuf++ = bits;

                             pixels_read++;

                         }
                     } else {

                         if (map_table)

                             bits = map_table[0];
                         else
                             bits = 0;
                         *destbuf++ = bits;
                         pixels_read ++;
                     }
                 }
             }
         }
     }

     if (get_bits(&gb, 8))

         av_log(avctx, AV_LOG_ERROR, "line overflow\n");

     (*srcbuf) += (get_bits_count(&gb) + 7) >> 3;
 
     return pixels_read;
 }

 static int dvbsub_read_8bit_string(AVCodecContext *avctx,
                                    uint8_t *destbuf, int dbuf_len,

                                     const uint8_t **srcbuf, int buf_size,

                                     int non_mod, uint8_t *map_table, int x_pos)

 {

     const uint8_t *sbuf_end = (*srcbuf) + buf_size;

     int bits;
     int run_length;

     int pixels_read = x_pos;
 
     destbuf += x_pos;

     while (*srcbuf < sbuf_end && pixels_read < dbuf_len) {
         bits = *(*srcbuf)++;

         if (bits) {

             if (non_mod != 1 || bits != 1) {

                 if (map_table)

                     *destbuf++ = map_table[bits];
                 else
                     *destbuf++ = bits;
             }
             pixels_read++;
         } else {
             bits = *(*srcbuf)++;
             run_length = bits & 0x7f;
             if ((bits & 0x80) == 0) {
                 if (run_length == 0) {
                     return pixels_read;
                 }

                 bits = 0;

             } else {
                 bits = *(*srcbuf)++;

             }

             if (non_mod == 1 && bits == 1)
                 pixels_read += run_length;
             else {

                 if (map_table)

                     bits = map_table[bits];

                 while (run_length-- > 0 && pixels_read < dbuf_len) {
                     *destbuf++ = bits;
                     pixels_read++;
                 }
             }
         }
     }

     if (*(*srcbuf)++)

         av_log(avctx, AV_LOG_ERROR, "line overflow\n");

     return pixels_read;
 }

 static void compute_default_clut(AVSubtitleRect *rect, int w, int h)

 {
     uint8_t list[256] = {0};
     uint8_t list_inv[256];
     int counttab[256] = {0};
     int count, i, x, y;
 

 #define V(x,y) rect->data[0][(x) + (y)*rect->linesize[0]]

     for (y = 0; y<h; y++) {
         for (x = 0; x<w; x++) {
             int v = V(x,y) + 1;
             int vl = x     ? V(x-1,y) + 1 : 0;
             int vr = x+1<w ? V(x+1,y) + 1 : 0;
             int vt = y     ? V(x,y-1) + 1 : 0;
             int vb = y+1<h ? V(x,y+1) + 1 : 0;
             counttab[v-1] += !!((v!=vl) + (v!=vr) + (v!=vt) + (v!=vb));
         }
     }

 #define L(x,y) list[ rect->data[0][(x) + (y)*rect->linesize[0]] ]

 
     for (i = 0; i<256; i++) {
         int scoretab[256] = {0};
         int bestscore = 0;
         int bestv = 0;
         for (y = 0; y<h; y++) {
             for (x = 0; x<w; x++) {

                 int v = rect->data[0][x + y*rect->linesize[0]];

                 int l_m = list[v];
                 int l_l = x     ? L(x-1, y) : 1;
                 int l_r = x+1<w ? L(x+1, y) : 1;
                 int l_t = y     ? L(x, y-1) : 1;
                 int l_b = y+1<h ? L(x, y+1) : 1;
                 int score;
                 if (l_m)
                     continue;
                 scoretab[v] += l_l + l_r + l_t + l_b;
                 score = 1024LL*scoretab[v] / counttab[v];
                 if (score > bestscore) {
                     bestscore = score;
                     bestv = v;
                 }
             }
         }
         if (!bestscore)
             break;
         list    [ bestv ] = 1;
         list_inv[     i ] = bestv;
     }
 

     count = FFMAX(i - 1, 1);

     for (i--; i>=0; i--) {
         int v = i*255/count;

         AV_WN32(rect->data[1] + 4*list_inv[i], RGBA(v/2,v,v/2,v));

     }
 }
 
 

 static int save_subtitle_set(AVCodecContext *avctx, AVSubtitle *sub, int *got_output)

 {
     DVBSubContext *ctx = avctx->priv_data;
     DVBSubRegionDisplay *display;
     DVBSubDisplayDefinition *display_def = ctx->display_definition;
     DVBSubRegion *region;
     AVSubtitleRect *rect;
     DVBSubCLUT *clut;
     uint32_t *clut_table;

     int i;

     int offset_x=0, offset_y=0;

     int ret = 0;

 
 
     if (display_def) {
         offset_x = display_def->x;
         offset_y = display_def->y;
     }
 

     /* Not touching AVSubtitles again*/
     if(sub->num_rects) {

         avpriv_request_sample(ctx, "Different Version of Segment asked Twice");

         return AVERROR_PATCHWELCOME;

     }

     for (display = ctx->display_list; display; display = display->next) {
         region = get_region(ctx, display->region_id);
         if (region && region->dirty)
             sub->num_rects++;
     }
 

     if(ctx->compute_edt == 0) {
         sub->end_display_time = ctx->time_out * 1000;
         *got_output = 1;
     } else if (ctx->prev_start != AV_NOPTS_VALUE) {
         sub->end_display_time = av_rescale_q((sub->pts - ctx->prev_start ), AV_TIME_BASE_Q, (AVRational){ 1, 1000 }) - 1;
         *got_output = 1;
     }

     if (sub->num_rects > 0) {

         sub->rects = av_mallocz_array(sizeof(*sub->rects), sub->num_rects);

         if (!sub->rects) {
             ret = AVERROR(ENOMEM);
             goto fail;
         }

         for(i=0; i<sub->num_rects; i++)
             sub->rects[i] = av_mallocz(sizeof(*sub->rects[i]));
 
         i = 0;
 
         for (display = ctx->display_list; display; display = display->next) {
             region = get_region(ctx, display->region_id);
 
             if (!region)
                 continue;
 
             if (!region->dirty)
                 continue;
 
             rect = sub->rects[i];
             rect->x = display->x_pos + offset_x;
             rect->y = display->y_pos + offset_y;
             rect->w = region->width;
             rect->h = region->height;
             rect->nb_colors = (1 << region->depth);
             rect->type      = SUBTITLE_BITMAP;

             rect->linesize[0] = region->width;

 
             clut = get_clut(ctx, region->clut);
 
             if (!clut)
                 clut = &default_clut;
 
             switch (region->depth) {
             case 2:
                 clut_table = clut->clut4;
                 break;
             case 8:
                 clut_table = clut->clut256;
                 break;
             case 4:
             default:
                 clut_table = clut->clut16;
                 break;
             }

             rect->data[1] = av_mallocz(AVPALETTE_SIZE);
             if (!rect->data[1]) {

                 ret = AVERROR(ENOMEM);
                 goto fail;

             }

             memcpy(rect->data[1], clut_table, (1 << region->depth) * sizeof(uint32_t));

             rect->data[0] = av_malloc(region->buf_size);
             if (!rect->data[0]) {

                 ret = AVERROR(ENOMEM);
                 goto fail;

             }
 

             memcpy(rect->data[0], region->pbuf, region->buf_size);

             if ((clut == &default_clut && ctx->compute_clut == -1) || ctx->compute_clut == 1)

                 compute_default_clut(rect, rect->w, rect->h);
 
 #if FF_API_AVPICTURE
 FF_DISABLE_DEPRECATION_WARNINGS

 {
             int j;

             for (j = 0; j < 4; j++) {
                 rect->pict.data[j] = rect->data[j];
                 rect->pict.linesize[j] = rect->linesize[j];
             }

 }

 FF_ENABLE_DEPRECATION_WARNINGS
 #endif

             i++;
         }
     }

 
     return 0;

 fail:
     if (sub->rects) {
         for(i=0; i<sub->num_rects; i++) {
             rect = sub->rects[i];
             if (rect) {

                 av_freep(&rect->data[0]);
                 av_freep(&rect->data[1]);

             }
             av_freep(&sub->rects[i]);
         }
         av_freep(&sub->rects);
     }
     sub->num_rects = 0;
     return ret;

 }

 
 static void dvbsub_parse_pixel_data_block(AVCodecContext *avctx, DVBSubObjectDisplay *display,

                                           const uint8_t *buf, int buf_size, int top_bottom, int non_mod)

 {

     DVBSubContext *ctx = avctx->priv_data;

 
     DVBSubRegion *region = get_region(ctx, display->region_id);

     const uint8_t *buf_end = buf + buf_size;

     uint8_t *pbuf;
     int x_pos, y_pos;
     int i;

     uint8_t map2to4[] = { 0x0,  0x7,  0x8,  0xf};
     uint8_t map2to8[] = {0x00, 0x77, 0x88, 0xff};

     uint8_t map4to8[] = {0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,

                          0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff};
     uint8_t *map_table;

 #if 0

     ff_dlog(avctx, "DVB pixel block size %d, %s field:\n", buf_size,

             top_bottom ? "bottom" : "top");

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

         if (i % 16 == 0)

             ff_dlog(avctx, "0x%8p: ", buf+i);

         ff_dlog(avctx, "%02x ", buf[i]);

         if (i % 16 == 15)

             ff_dlog(avctx, "\n");

     }

     if (i % 16)

         ff_dlog(avctx, "\n");

 #endif

     if (!region)

         return;

     pbuf = region->pbuf;

     region->dirty = 1;

     x_pos = display->x_pos;
     y_pos = display->y_pos;

     y_pos += top_bottom;

 
     while (buf < buf_end) {

         if ((*buf!=0xf0 && x_pos >= region->width) || y_pos >= region->height) {

             av_log(avctx, AV_LOG_ERROR, "Invalid object location! %d-%d %d-%d %02x\n", x_pos, region->width, y_pos, region->height, *buf);

             return;
         }

         switch (*buf++) {
         case 0x10:
             if (region->depth == 8)
                 map_table = map2to8;
             else if (region->depth == 4)
                 map_table = map2to4;
             else
                 map_table = NULL;

             x_pos = dvbsub_read_2bit_string(avctx, pbuf + (y_pos * region->width),

                                             region->width, &buf, buf_end - buf,
                                             non_mod, map_table, x_pos);

             break;
         case 0x11:
             if (region->depth < 4) {
                 av_log(avctx, AV_LOG_ERROR, "4-bit pixel string in %d-bit region!\n", region->depth);
                 return;
             }

             if (region->depth == 8)
                 map_table = map4to8;
             else
                 map_table = NULL;

             x_pos = dvbsub_read_4bit_string(avctx, pbuf + (y_pos * region->width),

                                             region->width, &buf, buf_end - buf,
                                             non_mod, map_table, x_pos);

             break;
         case 0x12:
             if (region->depth < 8) {
                 av_log(avctx, AV_LOG_ERROR, "8-bit pixel string in %d-bit region!\n", region->depth);
                 return;
             }

             x_pos = dvbsub_read_8bit_string(avctx, pbuf + (y_pos * region->width),

                                             region->width, &buf, buf_end - buf,
                                             non_mod, NULL, x_pos);

             break;

         case 0x20:
             map2to4[0] = (*buf) >> 4;
             map2to4[1] = (*buf++) & 0xf;
             map2to4[2] = (*buf) >> 4;
             map2to4[3] = (*buf++) & 0xf;
             break;
         case 0x21:
             for (i = 0; i < 4; i++)
                 map2to8[i] = *buf++;
             break;
         case 0x22:
             for (i = 0; i < 16; i++)
                 map4to8[i] = *buf++;
             break;

         case 0xf0:
             x_pos = display->x_pos;
             y_pos += 2;
             break;
         default:
             av_log(avctx, AV_LOG_INFO, "Unknown/unsupported pixel block 0x%x\n", *(buf-1));
         }
     }

 }
 

 static int dvbsub_parse_object_segment(AVCodecContext *avctx,
                                        const uint8_t *buf, int buf_size)

 {

     DVBSubContext *ctx = avctx->priv_data;

     const uint8_t *buf_end = buf + buf_size;

     int object_id;
     DVBSubObject *object;
     DVBSubObjectDisplay *display;
     int top_field_len, bottom_field_len;

     int coding_method, non_modifying_color;

     object_id = AV_RB16(buf);

     buf += 2;

     object = get_object(ctx, object_id);
 

     if (!object)

         return AVERROR_INVALIDDATA;

     coding_method = ((*buf) >> 2) & 3;

     non_modifying_color = ((*buf++) >> 1) & 1;

     if (coding_method == 0) {

         top_field_len = AV_RB16(buf);

         buf += 2;

         bottom_field_len = AV_RB16(buf);

         buf += 2;

         if (buf + top_field_len + bottom_field_len > buf_end) {

             av_log(avctx, AV_LOG_ERROR, "Field data size %d+%d too large\n", top_field_len, bottom_field_len);

             return AVERROR_INVALIDDATA;

         }
 

         for (display = object->display_list; display; display = display->object_list_next) {

             const uint8_t *block = buf;
             int bfl = bottom_field_len;

 
             dvbsub_parse_pixel_data_block(avctx, display, block, top_field_len, 0,

                                             non_modifying_color);

 
             if (bottom_field_len > 0)
                 block = buf + top_field_len;
             else

                 bfl = top_field_len;

             dvbsub_parse_pixel_data_block(avctx, display, block, bfl, 1,

                                             non_modifying_color);

         }

 /*  } else if (coding_method == 1) {*/

     } else {
         av_log(avctx, AV_LOG_ERROR, "Unknown object coding %d\n", coding_method);
     }

     return 0;

 }
 

 static int dvbsub_parse_clut_segment(AVCodecContext *avctx,

                                      const uint8_t *buf, int buf_size)

 {

     DVBSubContext *ctx = avctx->priv_data;

     const uint8_t *buf_end = buf + buf_size;

     int i, clut_id;

     int version;

     DVBSubCLUT *clut;
     int entry_id, depth , full_range;
     int y, cr, cb, alpha;
     int r, g, b, r_add, g_add, b_add;
 

     ff_dlog(avctx, "DVB clut packet:\n");

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

         ff_dlog(avctx, "%02x ", buf[i]);

         if (i % 16 == 15)

             ff_dlog(avctx, "\n");

     }

     if (i % 16)

         ff_dlog(avctx, "\n");

 
     clut_id = *buf++;

     version = ((*buf)>>4)&15;

     buf += 1;

     clut = get_clut(ctx, clut_id);

     if (!clut) {

         clut = av_malloc(sizeof(DVBSubCLUT));

         if (!clut)
             return AVERROR(ENOMEM);

         memcpy(clut, &default_clut, sizeof(DVBSubCLUT));
 
         clut->id = clut_id;

         clut->version = -1;

 
         clut->next = ctx->clut_list;

         ctx->clut_list = clut;
     }

     if (clut->version != version) {
 
     clut->version = version;
 

     while (buf + 4 < buf_end) {

         entry_id = *buf++;

         depth = (*buf) & 0xe0;

         if (depth == 0) {
             av_log(avctx, AV_LOG_ERROR, "Invalid clut depth 0x%x!\n", *buf);
         }

         full_range = (*buf++) & 1;

         if (full_range) {
             y = *buf++;
             cr = *buf++;
             cb = *buf++;
             alpha = *buf++;
         } else {
             y = buf[0] & 0xfc;
             cr = (((buf[0] & 3) << 2) | ((buf[1] >> 6) & 3)) << 4;
             cb = (buf[1] << 2) & 0xf0;
             alpha = (buf[1] << 6) & 0xc0;

             buf += 2;
         }

         if (y == 0)
             alpha = 0xff;

         YUV_TO_RGB1_CCIR(cb, cr);
         YUV_TO_RGB2_CCIR(r, g, b, y);

         ff_dlog(avctx, "clut %d := (%d,%d,%d,%d)\n", entry_id, r, g, b, alpha);

         if (!!(depth & 0x80) + !!(depth & 0x40) + !!(depth & 0x20) > 1) {

             ff_dlog(avctx, "More than one bit level marked: %x\n", depth);

             if (avctx->strict_std_compliance > FF_COMPLIANCE_NORMAL)
                 return AVERROR_INVALIDDATA;
         }

         if (depth & 0x80 && entry_id < 4)

             clut->clut4[entry_id] = RGBA(r,g,b,255 - alpha);

         else if (depth & 0x40 && entry_id < 16)

             clut->clut16[entry_id] = RGBA(r,g,b,255 - alpha);

         else if (depth & 0x20)

             clut->clut256[entry_id] = RGBA(r,g,b,255 - alpha);
     }

     }

     return 0;

 }
 
 

 static int dvbsub_parse_region_segment(AVCodecContext *avctx,

                                        const uint8_t *buf, int buf_size)

 {

     DVBSubContext *ctx = avctx->priv_data;

     const uint8_t *buf_end = buf + buf_size;

     int region_id, object_id;

     int av_unused version;

     DVBSubRegion *region;
     DVBSubObject *object;
     DVBSubObjectDisplay *display;
     int fill;

     int ret;

     if (buf_size < 10)

         return AVERROR_INVALIDDATA;

     region_id = *buf++;

     region = get_region(ctx, region_id);

     if (!region) {

         region = av_mallocz(sizeof(DVBSubRegion));

         if (!region)

             return AVERROR(ENOMEM);

         region->id = region_id;

         region->version = -1;

         region->next = ctx->region_list;
         ctx->region_list = region;
     }

     version = ((*buf)>>4) & 15;

     fill = ((*buf++) >> 3) & 1;

     region->width = AV_RB16(buf);

     buf += 2;

     region->height = AV_RB16(buf);

     buf += 2;

     ret = av_image_check_size2(region->width, region->height, avctx->max_pixels, AV_PIX_FMT_PAL8, 0, avctx);

     if (ret >= 0 && region->width * region->height * 2 > 320 * 1024 * 8) {
         ret = AVERROR_INVALIDDATA;
         av_log(avctx, AV_LOG_ERROR, "Pixel buffer memory constraint violated\n");
     }

     if (ret < 0) {
         region->width= region->height= 0;
         return ret;
     }
 

     if (region->width * region->height != region->buf_size) {

         av_free(region->pbuf);

         region->buf_size = region->width * region->height;

         region->pbuf = av_malloc(region->buf_size);

         if (!region->pbuf) {
             region->buf_size =
             region->width =
             region->height = 0;

             return AVERROR(ENOMEM);

         }

         fill = 1;

         region->dirty = 0;

     }

     region->depth = 1 << (((*buf++) >> 2) & 7);

     if(region->depth<2 || region->depth>8){
         av_log(avctx, AV_LOG_ERROR, "region depth %d is invalid\n", region->depth);
         region->depth= 4;
     }

     region->clut = *buf++;

     if (region->depth == 8) {

         region->bgcolor = *buf++;

         buf += 1;
     } else {

         buf += 1;

         if (region->depth == 4)

             region->bgcolor = (((*buf++) >> 4) & 15);

         else

             region->bgcolor = (((*buf++) >> 2) & 3);

     }
 

     ff_dlog(avctx, "Region %d, (%dx%d)\n", region_id, region->width, region->height);

 
     if (fill) {

         memset(region->pbuf, region->bgcolor, region->buf_size);

         ff_dlog(avctx, "Fill region (%d)\n", region->bgcolor);

     }
 
     delete_region_display_list(ctx, region);
 
     while (buf + 5 < buf_end) {

         object_id = AV_RB16(buf);

         buf += 2;

         object = get_object(ctx, object_id);
 

         if (!object) {

             object = av_mallocz(sizeof(DVBSubObject));

             if (!object)
                 return AVERROR(ENOMEM);

             object->id = object_id;
             object->next = ctx->object_list;
             ctx->object_list = object;
         }

         object->type = (*buf) >> 6;

         display = av_mallocz(sizeof(DVBSubObjectDisplay));

         if (!display)
             return AVERROR(ENOMEM);

         display->object_id = object_id;
         display->region_id = region_id;

         display->x_pos = AV_RB16(buf) & 0xfff;

         buf += 2;

         display->y_pos = AV_RB16(buf) & 0xfff;

         buf += 2;

         if (display->x_pos >= region->width ||
             display->y_pos >= region->height) {
             av_log(avctx, AV_LOG_ERROR, "Object outside region\n");
             av_free(display);
             return AVERROR_INVALIDDATA;
         }
 

         if ((object->type == 1 || object->type == 2) && buf+1 < buf_end) {

             display->fgcolor = *buf++;
             display->bgcolor = *buf++;

         }

         display->region_list_next = region->display_list;
         region->display_list = display;

         display->object_list_next = object->display_list;
         object->display_list = display;
     }

 
     return 0;

 }
 

 static int dvbsub_parse_page_segment(AVCodecContext *avctx,

                                      const uint8_t *buf, int buf_size, AVSubtitle *sub, int *got_output)

 {

     DVBSubContext *ctx = avctx->priv_data;

     DVBSubRegionDisplay *display;
     DVBSubRegionDisplay *tmp_display_list, **tmp_ptr;

     const uint8_t *buf_end = buf + buf_size;

     int region_id;
     int page_state;

     int timeout;
     int version;

     if (buf_size < 1)

         return AVERROR_INVALIDDATA;

     timeout = *buf++;
     version = ((*buf)>>4) & 15;

     page_state = ((*buf++) >> 2) & 3;

     if (ctx->version == version) {

         return 0;

     }

 
     ctx->time_out = timeout;
     ctx->version = version;
 

     ff_dlog(avctx, "Page time out %ds, state %d\n", ctx->time_out, page_state);

     if(ctx->compute_edt == 1)
         save_subtitle_set(avctx, sub, got_output);
 

     if (page_state == 1 || page_state == 2) {

         delete_regions(ctx);
         delete_objects(ctx);
         delete_cluts(ctx);

     }

     tmp_display_list = ctx->display_list;
     ctx->display_list = NULL;

     while (buf + 5 < buf_end) {
         region_id = *buf++;
         buf += 1;

         display = ctx->display_list;
         while (display && display->region_id != region_id) {
             display = display->next;
         }
         if (display) {
             av_log(avctx, AV_LOG_ERROR, "duplicate region\n");
             break;
         }
 

         display = tmp_display_list;
         tmp_ptr = &tmp_display_list;

         while (display && display->region_id != region_id) {

             tmp_ptr = &display->next;
             display = display->next;
         }

         if (!display) {

             display = av_mallocz(sizeof(DVBSubRegionDisplay));

             if (!display)
                 return AVERROR(ENOMEM);
         }

         display->region_id = region_id;

         display->x_pos = AV_RB16(buf);

         buf += 2;

         display->y_pos = AV_RB16(buf);

         buf += 2;

         *tmp_ptr = display->next;

         display->next = ctx->display_list;
         ctx->display_list = display;

         ff_dlog(avctx, "Region %d, (%d,%d)\n", region_id, display->x_pos, display->y_pos);

     }

     while (tmp_display_list) {

         display = tmp_display_list;

         tmp_display_list = display->next;

         av_freep(&display);

     }

     return 0;

 }
 
 

 #ifdef DEBUG

 static void png_save(DVBSubContext *ctx, const char *filename, uint32_t *bitmap, int w, int h)

 {
     int x, y, v;
     FILE *f;
     char fname[40], fname2[40];
     char command[1024];
 
     snprintf(fname, sizeof(fname), "%s.ppm", filename);
 
     f = fopen(fname, "w");
     if (!f) {
         perror(fname);
         return;
     }
     fprintf(f, "P6\n"
             "%d %d\n"
             "%d\n",
             w, h, 255);
     for(y = 0; y < h; y++) {
         for(x = 0; x < w; x++) {
             v = bitmap[y * w + x];
             putc((v >> 16) & 0xff, f);
             putc((v >> 8) & 0xff, f);
             putc((v >> 0) & 0xff, f);
         }
     }
     fclose(f);
 
 
     snprintf(fname2, sizeof(fname2), "%s-a.pgm", filename);
 
     f = fopen(fname2, "w");
     if (!f) {
         perror(fname2);
         return;
     }
     fprintf(f, "P5\n"
             "%d %d\n"
             "%d\n",
             w, h, 255);
     for(y = 0; y < h; y++) {
         for(x = 0; x < w; x++) {
             v = bitmap[y * w + x];
             putc((v >> 24) & 0xff, f);
         }
     }
     fclose(f);
 
     snprintf(command, sizeof(command), "pnmtopng -alpha %s %s > %s.png 2> /dev/null", fname2, fname, filename);
     if (system(command) != 0) {

         av_log(ctx, AV_LOG_ERROR, "Error running pnmtopng\n");

         return;
     }
 
     snprintf(command, sizeof(command), "rm %s %s", fname, fname2);
     if (system(command) != 0) {

         av_log(ctx, AV_LOG_ERROR, "Error removing %s and %s\n", fname, fname2);

         return;
     }
 }
 

 static int save_display_set(DVBSubContext *ctx)

 {
     DVBSubRegion *region;
     DVBSubRegionDisplay *display;
     DVBSubCLUT *clut;
     uint32_t *clut_table;
     int x_pos, y_pos, width, height;
     int x, y, y_off, x_off;
     uint32_t *pbuf;
     char filename[32];
     static int fileno_index = 0;
 
     x_pos = -1;
     y_pos = -1;
     width = 0;
     height = 0;

     for (display = ctx->display_list; display; display = display->next) {

         region = get_region(ctx, display->region_id);

         if (!region)

             return -1;

         if (x_pos == -1) {
             x_pos = display->x_pos;
             y_pos = display->y_pos;
             width = region->width;
             height = region->height;
         } else {
             if (display->x_pos < x_pos) {
                 width += (x_pos - display->x_pos);
                 x_pos = display->x_pos;
             }

             if (display->y_pos < y_pos) {
                 height += (y_pos - display->y_pos);
                 y_pos = display->y_pos;
             }

             if (display->x_pos + region->width > x_pos + width) {
                 width = display->x_pos + region->width - x_pos;
             }

             if (display->y_pos + region->height > y_pos + height) {
                 height = display->y_pos + region->height - y_pos;
             }
         }
     }

     if (x_pos >= 0) {

         pbuf = av_malloc(width * height * 4);

         if (!pbuf)

             return -1;

         for (display = ctx->display_list; display; display = display->next) {

             region = get_region(ctx, display->region_id);
 

             if (!region)

                 return -1;

             x_off = display->x_pos - x_pos;
             y_off = display->y_pos - y_pos;
 
             clut = get_clut(ctx, region->clut);
 

             if (!clut)

                 clut = &default_clut;
 
             switch (region->depth) {
             case 2:
                 clut_table = clut->clut4;
                 break;
             case 8:
                 clut_table = clut->clut256;
                 break;
             case 4:
             default:
                 clut_table = clut->clut16;
                 break;
             }

             for (y = 0; y < region->height; y++) {
                 for (x = 0; x < region->width; x++) {

                     pbuf[((y + y_off) * width) + x_off + x] =

                         clut_table[region->pbuf[y * region->width + x]];
                 }
             }
 

         }

         snprintf(filename, sizeof(filename), "dvbs.%d", fileno_index);

         png_save(ctx, filename, pbuf, width, height);

         av_freep(&pbuf);

     }

     fileno_index++;

     return 0;

 }

 #endif /* DEBUG */

 static int dvbsub_parse_display_definition_segment(AVCodecContext *avctx,

                                                    const uint8_t *buf,
                                                    int buf_size)

 {
     DVBSubContext *ctx = avctx->priv_data;
     DVBSubDisplayDefinition *display_def = ctx->display_definition;
     int dds_version, info_byte;
 
     if (buf_size < 5)

         return AVERROR_INVALIDDATA;

 
     info_byte   = bytestream_get_byte(&buf);
     dds_version = info_byte >> 4;
     if (display_def && display_def->version == dds_version)

         return 0; // already have this display definition version

 
     if (!display_def) {
         display_def             = av_mallocz(sizeof(*display_def));

         if (!display_def)
             return AVERROR(ENOMEM);

         ctx->display_definition = display_def;
     }
 
     display_def->version = dds_version;
     display_def->x       = 0;
     display_def->y       = 0;
     display_def->width   = bytestream_get_be16(&buf) + 1;
     display_def->height  = bytestream_get_be16(&buf) + 1;

     if (!avctx->width || !avctx->height) {
         avctx->width  = display_def->width;
         avctx->height = display_def->height;
     }

 
     if (info_byte & 1<<3) { // display_window_flag

         if (buf_size < 13)
             return AVERROR_INVALIDDATA;
 

         display_def->x = bytestream_get_be16(&buf);
         display_def->width  = bytestream_get_be16(&buf) - display_def->x + 1;

         display_def->y = bytestream_get_be16(&buf);

         display_def->height = bytestream_get_be16(&buf) - display_def->y + 1;
     }

 
     return 0;

 }
 

 static int dvbsub_display_end_segment(AVCodecContext *avctx, const uint8_t *buf,

                                       int buf_size, AVSubtitle *sub,int *got_output)

 {

     DVBSubContext *ctx = avctx->priv_data;

     if(ctx->compute_edt == 0)
         save_subtitle_set(avctx, sub, got_output);

 #ifdef DEBUG

     save_display_set(ctx);
 #endif

     return 0;

 }
 
 static int dvbsub_decode(AVCodecContext *avctx,
                          void *data, int *data_size,

                          AVPacket *avpkt)

 {

     const uint8_t *buf = avpkt->data;
     int buf_size = avpkt->size;

     DVBSubContext *ctx = avctx->priv_data;
     AVSubtitle *sub = data;

     const uint8_t *p, *p_end;

     int segment_type;
     int page_id;
     int segment_length;
     int i;

     int ret = 0;

     int got_segment = 0;

     int got_dds = 0;

     ff_dlog(avctx, "DVB sub packet:\n");

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

         ff_dlog(avctx, "%02x ", buf[i]);

         if (i % 16 == 15)

             ff_dlog(avctx, "\n");

     }

     if (i % 16)

         ff_dlog(avctx, "\n");

     if (buf_size <= 6 || *buf != 0x0f) {

         ff_dlog(avctx, "incomplete or broken packet");

         return AVERROR_INVALIDDATA;

     }

     p = buf;
     p_end = buf + buf_size;

     while (p_end - p >= 6 && *p == 0x0f) {

         p += 1;
         segment_type = *p++;

         page_id = AV_RB16(p);

         p += 2;

         segment_length = AV_RB16(p);

         p += 2;

         if (avctx->debug & FF_DEBUG_STARTCODE) {
             av_log(avctx, AV_LOG_DEBUG, "segment_type:%d page_id:%d segment_length:%d\n", segment_type, page_id, segment_length);
         }
 

         if (p_end - p < segment_length) {

             ff_dlog(avctx, "incomplete or broken packet");

             ret = -1;
             goto end;

         }
 

         if (page_id == ctx->composition_id || page_id == ctx->ancillary_id ||
             ctx->composition_id == -1 || ctx->ancillary_id == -1) {

             int ret = 0;

             switch (segment_type) {
             case DVBSUB_PAGE_SEGMENT:

                 ret = dvbsub_parse_page_segment(avctx, p, segment_length, sub, data_size);

                 got_segment |= 1;

                 break;
             case DVBSUB_REGION_SEGMENT:

                 ret = dvbsub_parse_region_segment(avctx, p, segment_length);

                 got_segment |= 2;

                 break;
             case DVBSUB_CLUT_SEGMENT:

                 ret = dvbsub_parse_clut_segment(avctx, p, segment_length);

                 if (ret < 0) goto end;

                 got_segment |= 4;

                 break;
             case DVBSUB_OBJECT_SEGMENT:

                 ret = dvbsub_parse_object_segment(avctx, p, segment_length);

                 got_segment |= 8;

                 break;

             case DVBSUB_DISPLAYDEFINITION_SEGMENT:

                 ret = dvbsub_parse_display_definition_segment(avctx, p,
                                                               segment_length);

                 got_dds = 1;

                 break;

             case DVBSUB_DISPLAY_SEGMENT:

                 ret = dvbsub_display_end_segment(avctx, p, segment_length, sub, data_size);

                 if (got_segment == 15 && !got_dds && !avctx->width && !avctx->height) {
                     // Default from ETSI EN 300 743 V1.3.1 (7.2.1)
                     avctx->width  = 720;
                     avctx->height = 576;
                 }

                 got_segment |= 16;

                 break;
             default:

                 ff_dlog(avctx, "Subtitling segment type 0x%x, page id %d, length %d\n",

                         segment_type, page_id, segment_length);
                 break;
             }

             if (ret < 0)

                 goto end;

         }
 
         p += segment_length;
     }

     // Some streams do not send a display segment but if we have all the other
     // segments then we need no further data.

     if (got_segment == 15) {

         av_log(avctx, AV_LOG_DEBUG, "Missing display_end_segment, emulating\n");

         dvbsub_display_end_segment(avctx, p, 0, sub, data_size);
     }
 
 end:
     if(ret < 0) {
         *data_size = 0;
         avsubtitle_free(sub);
         return ret;
     } else {
         if(ctx->compute_edt == 1 )
             FFSWAP(int64_t, ctx->prev_start, sub->pts);

     }

     return p - buf;

 }
 

 #define DS AV_OPT_FLAG_DECODING_PARAM | AV_OPT_FLAG_SUBTITLE_PARAM

 static const AVOption options[] = {

     {"compute_edt", "compute end of time using pts or timeout", offsetof(DVBSubContext, compute_edt), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, DS},
     {"compute_clut", "compute clut when not available(-1) or always(1) or never(0)", offsetof(DVBSubContext, compute_clut), AV_OPT_TYPE_BOOL, {.i64 = -1}, -1, 1, DS},

     {"dvb_substream", "", offsetof(DVBSubContext, substream), AV_OPT_TYPE_INT, {.i64 = -1}, -1, 63, DS},

     {NULL}
 };
 static const AVClass dvbsubdec_class = {
     .class_name = "DVB Sub Decoder",
     .item_name  = av_default_item_name,
     .option     = options,
     .version    = LIBAVUTIL_VERSION_INT,
 };

 AVCodec ff_dvbsub_decoder = {

     .name           = "dvbsub",

     .long_name      = NULL_IF_CONFIG_SMALL("DVB subtitles"),

     .type           = AVMEDIA_TYPE_SUBTITLE,

     .id             = AV_CODEC_ID_DVB_SUBTITLE,

     .priv_data_size = sizeof(DVBSubContext),
     .init           = dvbsub_init_decoder,
     .close          = dvbsub_close_decoder,
     .decode         = dvbsub_decode,

     .priv_class     = &dvbsubdec_class,

 };