/*

  * DVD subtitle decoding

  * Copyright (c) 2005 Fabrice Bellard

  *

  * 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 "internal.h"
 

 #include "libavutil/attributes.h"

 #include "libavutil/colorspace.h"

 #include "libavutil/opt.h"

 #include "libavutil/imgutils.h"

 #include "libavutil/avstring.h"

 #include "libavutil/bswap.h"

 typedef struct DVDSubContext
 {

   AVClass *class;

   uint32_t palette[16];

   char    *palette_str;

   char    *ifo_str;

   int      has_palette;

   uint8_t  colormap[4];
   uint8_t  alpha[256];

   uint8_t  buf[0x10000];

   int      buf_size;

   int      forced_subs_only;

 #ifdef DEBUG
   int sub_id;
 #endif

 } DVDSubContext;
 

 static void yuv_a_to_rgba(const uint8_t *ycbcr, const uint8_t *alpha, uint32_t *rgba, int num_values)
 {

     const uint8_t *cm = ff_crop_tab + MAX_NEG_CROP;

     uint8_t r, g, b;
     int i, y, cb, cr;
     int r_add, g_add, b_add;
 
     for (i = num_values; i > 0; i--) {
         y = *ycbcr++;
         cr = *ycbcr++;

         cb = *ycbcr++;

         YUV_TO_RGB1_CCIR(cb, cr);
         YUV_TO_RGB2_CCIR(r, g, b, y);
         *rgba++ = (*alpha++ << 24) | (r << 16) | (g << 8) | b;
     }
 }
 
 static int decode_run_2bit(GetBitContext *gb, int *color)
 {
     unsigned int v, t;
 
     v = 0;
     for (t = 1; v < t && t <= 0x40; t <<= 2)
         v = (v << 4) | get_bits(gb, 4);
     *color = v & 3;
     if (v < 4) { /* Code for fill rest of line */
         return INT_MAX;
     }
     return v >> 2;
 }
 
 static int decode_run_8bit(GetBitContext *gb, int *color)

 {

     int len;
     int has_run = get_bits1(gb);
     if (get_bits1(gb))
         *color = get_bits(gb, 8);
     else
         *color = get_bits(gb, 2);
     if (has_run) {
         if (get_bits1(gb)) {
             len = get_bits(gb, 7);
             if (len == 0)
                 len = INT_MAX;
             else
                 len += 9;
         } else
             len = get_bits(gb, 3) + 2;
     } else
         len = 1;
     return len;

 }
 

 static int decode_rle(uint8_t *bitmap, int linesize, int w, int h,

                       const uint8_t *buf, int start, int buf_size, int is_8bit)

 {

     GetBitContext gb;
     int bit_len;
     int x, y, len, color;

     uint8_t *d;
 

     if (start >= buf_size)
         return -1;
 

     if (w <= 0 || h <= 0)
         return -1;
 

     bit_len = (buf_size - start) * 8;
     init_get_bits(&gb, buf + start, bit_len);
 

     x = 0;
     y = 0;
     d = bitmap;
     for(;;) {

         if (get_bits_count(&gb) > bit_len)

             return -1;

         if (is_8bit)
             len = decode_run_8bit(&gb, &color);
         else
             len = decode_run_2bit(&gb, &color);
         len = FFMIN(len, w - x);

         memset(d + x, color, len);
         x += len;
         if (x >= w) {
             y++;
             if (y >= h)
                 break;
             d += linesize;
             x = 0;
             /* byte align */

             align_get_bits(&gb);

         }
     }
     return 0;
 }
 

 static void guess_palette(DVDSubContext* ctx,
                           uint32_t *rgba_palette,

                           uint32_t subtitle_color)
 {

     static const uint8_t level_map[4][4] = {
         // this configuration (full range, lowest to highest) in tests
         // seemed most common, so assume this
         {0xff},
         {0x00, 0xff},
         {0x00, 0x80, 0xff},
         {0x00, 0x55, 0xaa, 0xff},
     };

     uint8_t color_used[16] = { 0 };

     int nb_opaque_colors, i, level, j, r, g, b;

     uint8_t *colormap = ctx->colormap, *alpha = ctx->alpha;

     if(ctx->has_palette) {
         for(i = 0; i < 4; i++)
             rgba_palette[i] = (ctx->palette[colormap[i]] & 0x00ffffff)

                               | ((alpha[i] * 17U) << 24);

         return;
     }
 

     for(i = 0; i < 4; i++)
         rgba_palette[i] = 0;
 
     nb_opaque_colors = 0;
     for(i = 0; i < 4; i++) {

         if (alpha[i] != 0 && !color_used[colormap[i]]) {
             color_used[colormap[i]] = 1;

             nb_opaque_colors++;
         }
     }

     if (nb_opaque_colors == 0)
         return;

     j = 0;

     memset(color_used, 0, 16);
     for(i = 0; i < 4; i++) {
         if (alpha[i] != 0) {

             if (!color_used[colormap[i]])  {

                 level = level_map[nb_opaque_colors][j];

                 r = (((subtitle_color >> 16) & 0xff) * level) >> 8;
                 g = (((subtitle_color >> 8) & 0xff) * level) >> 8;
                 b = (((subtitle_color >> 0) & 0xff) * level) >> 8;

                 rgba_palette[i] = b | (g << 8) | (r << 16) | ((alpha[i] * 17) << 24);

                 color_used[colormap[i]] = (i + 1);

                 j++;

             } else {

                 rgba_palette[i] = (rgba_palette[color_used[colormap[i]] - 1] & 0x00ffffff) |

                                     ((alpha[i] * 17) << 24);

             }
         }
     }
 }
 

 static void reset_rects(AVSubtitle *sub_header)
 {
     int i;
 

     if (sub_header->rects) {

         for (i = 0; i < sub_header->num_rects; i++) {
             av_freep(&sub_header->rects[i]->pict.data[0]);
             av_freep(&sub_header->rects[i]->pict.data[1]);
             av_freep(&sub_header->rects[i]);
         }
         av_freep(&sub_header->rects);
         sub_header->num_rects = 0;
     }
 }
 

 #define READ_OFFSET(a) (big_offsets ? AV_RB32(a) : AV_RB16(a))
 

 static int decode_dvd_subtitles(DVDSubContext *ctx, AVSubtitle *sub_header,

                                 const uint8_t *buf, int buf_size)
 {
     int cmd_pos, pos, cmd, x1, y1, x2, y2, offset1, offset2, next_cmd_pos;

     int big_offsets, offset_size, is_8bit = 0;

     const uint8_t *yuv_palette = NULL;

     uint8_t *colormap = ctx->colormap, *alpha = ctx->alpha;

     int date;

     int i;

     int is_menu = 0;

     if (buf_size < 10)

         return -1;
 

     if (AV_RB16(buf) == 0) {   /* HD subpicture with 4-byte offsets */
         big_offsets = 1;
         offset_size = 4;
         cmd_pos = 6;
     } else {
         big_offsets = 0;
         offset_size = 2;
         cmd_pos = 2;
     }
 
     cmd_pos = READ_OFFSET(buf + cmd_pos);
 

     if (cmd_pos < 0 || cmd_pos > buf_size - 2 - offset_size)
         return AVERROR(EAGAIN);
 

     while (cmd_pos > 0 && cmd_pos < buf_size - 2 - offset_size) {

         date = AV_RB16(buf + cmd_pos);

         next_cmd_pos = READ_OFFSET(buf + cmd_pos + 2);

         av_dlog(NULL, "cmd_pos=0x%04x next=0x%04x date=%d\n",

                 cmd_pos, next_cmd_pos, date);

         pos = cmd_pos + 2 + offset_size;

         offset1 = -1;
         offset2 = -1;
         x1 = y1 = x2 = y2 = 0;
         while (pos < buf_size) {
             cmd = buf[pos++];

             av_dlog(NULL, "cmd=%02x\n", cmd);

             switch(cmd) {
             case 0x00:

                 /* menu subpicture */
                 is_menu = 1;

                 break;
             case 0x01:
                 /* set start date */

                 sub_header->start_display_time = (date << 10) / 90;

                 break;
             case 0x02:
                 /* set end date */

                 sub_header->end_display_time = (date << 10) / 90;

                 break;
             case 0x03:

                 /* set colormap */

                 if ((buf_size - pos) < 2)
                     goto fail;

                 colormap[3] = buf[pos] >> 4;
                 colormap[2] = buf[pos] & 0x0f;
                 colormap[1] = buf[pos + 1] >> 4;
                 colormap[0] = buf[pos + 1] & 0x0f;

                 pos += 2;
                 break;
             case 0x04:
                 /* set alpha */
                 if ((buf_size - pos) < 2)
                     goto fail;

                 alpha[3] = buf[pos] >> 4;
                 alpha[2] = buf[pos] & 0x0f;
                 alpha[1] = buf[pos + 1] >> 4;
                 alpha[0] = buf[pos + 1] & 0x0f;

                 pos += 2;

             av_dlog(NULL, "alpha=%x%x%x%x\n", alpha[0],alpha[1],alpha[2],alpha[3]);

                 break;
             case 0x05:

             case 0x85:

                 if ((buf_size - pos) < 6)
                     goto fail;
                 x1 = (buf[pos] << 4) | (buf[pos + 1] >> 4);
                 x2 = ((buf[pos + 1] & 0x0f) << 8) | buf[pos + 2];
                 y1 = (buf[pos + 3] << 4) | (buf[pos + 4] >> 4);
                 y2 = ((buf[pos + 4] & 0x0f) << 8) | buf[pos + 5];

                 if (cmd & 0x80)
                     is_8bit = 1;

                 av_dlog(NULL, "x1=%d x2=%d y1=%d y2=%d\n", x1, x2, y1, y2);

                 pos += 6;
                 break;
             case 0x06:
                 if ((buf_size - pos) < 4)
                     goto fail;

                 offset1 = AV_RB16(buf + pos);
                 offset2 = AV_RB16(buf + pos + 2);

                 av_dlog(NULL, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2);

                 pos += 4;
                 break;

             case 0x86:
                 if ((buf_size - pos) < 8)
                     goto fail;
                 offset1 = AV_RB32(buf + pos);
                 offset2 = AV_RB32(buf + pos + 4);

                 av_dlog(NULL, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2);

                 pos += 8;
                 break;
 
             case 0x83:
                 /* HD set palette */
                 if ((buf_size - pos) < 768)
                     goto fail;
                 yuv_palette = buf + pos;
                 pos += 768;
                 break;
             case 0x84:
                 /* HD set contrast (alpha) */
                 if ((buf_size - pos) < 256)
                     goto fail;
                 for (i = 0; i < 256; i++)
                     alpha[i] = 0xFF - buf[pos+i];
                 pos += 256;
                 break;
 

             case 0xff:

                 goto the_end;

             default:

                 av_dlog(NULL, "unrecognised subpicture command 0x%x\n", cmd);

                 goto the_end;
             }
         }
     the_end:
         if (offset1 >= 0) {
             int w, h;
             uint8_t *bitmap;

             /* decode the bitmap */
             w = x2 - x1 + 1;
             if (w < 0)
                 w = 0;

             h = y2 - y1 + 1;

             if (h < 0)
                 h = 0;
             if (w > 0 && h > 0) {

                 reset_rects(sub_header);

                 sub_header->rects = av_mallocz(sizeof(*sub_header->rects));

                 if (!sub_header->rects)
                     goto fail;

                 sub_header->rects[0] = av_mallocz(sizeof(AVSubtitleRect));

                 if (!sub_header->rects[0])
                     goto fail;

                 sub_header->num_rects = 1;

                 bitmap = sub_header->rects[0]->pict.data[0] = av_malloc(w * h);
                 if (!bitmap)
                     goto fail;

                 if (decode_rle(bitmap, w * 2, w, (h + 1) / 2,
                                buf, offset1, buf_size, is_8bit) < 0)
                     goto fail;
                 if (decode_rle(bitmap + w, w * 2, w, h / 2,
                                buf, offset2, buf_size, is_8bit) < 0)
                     goto fail;

                 sub_header->rects[0]->pict.data[1] = av_mallocz(AVPALETTE_SIZE);

                 if (!sub_header->rects[0]->pict.data[1])
                     goto fail;

                 if (is_8bit) {

                     if (!yuv_palette)

                         goto fail;

                     sub_header->rects[0]->nb_colors = 256;

                     yuv_a_to_rgba(yuv_palette, alpha, (uint32_t*)sub_header->rects[0]->pict.data[1], 256);

                 } else {

                     sub_header->rects[0]->nb_colors = 4;

                     guess_palette(ctx, (uint32_t*)sub_header->rects[0]->pict.data[1],

                                   0xffff00);

                 }

                 sub_header->rects[0]->x = x1;
                 sub_header->rects[0]->y = y1;
                 sub_header->rects[0]->w = w;
                 sub_header->rects[0]->h = h;

                 sub_header->rects[0]->type = SUBTITLE_BITMAP;

                 sub_header->rects[0]->pict.linesize[0] = w;

                 sub_header->rects[0]->flags = is_menu ? AV_SUBTITLE_FLAG_FORCED : 0;

             }
         }

         if (next_cmd_pos < cmd_pos) {
             av_log(NULL, AV_LOG_ERROR, "Invalid command offset\n");
             break;
         }

         if (next_cmd_pos == cmd_pos)
             break;
         cmd_pos = next_cmd_pos;
     }

     if (sub_header->num_rects > 0)

         return is_menu;

  fail:

     reset_rects(sub_header);

     return -1;
 }
 

 static int is_transp(const uint8_t *buf, int pitch, int n,

                      const uint8_t *transp_color)
 {
     int i;
     for(i = 0; i < n; i++) {
         if (!transp_color[*buf])
             return 0;
         buf += pitch;
     }
     return 1;
 }
 
 /* return 0 if empty rectangle, 1 if non empty */

 static int find_smallest_bounding_rectangle(AVSubtitle *s)

 {

     uint8_t transp_color[256] = { 0 };

     int y1, y2, x1, x2, y, w, h, i;
     uint8_t *bitmap;
 

     if (s->num_rects == 0 || !s->rects || s->rects[0]->w <= 0 || s->rects[0]->h <= 0)

         return 0;
 

     for(i = 0; i < s->rects[0]->nb_colors; i++) {

         if ((((uint32_t*)s->rects[0]->pict.data[1])[i] >> 24) == 0)

             transp_color[i] = 1;
     }
     y1 = 0;

     while (y1 < s->rects[0]->h && is_transp(s->rects[0]->pict.data[0] + y1 * s->rects[0]->pict.linesize[0],

                                   1, s->rects[0]->w, transp_color))

         y1++;

     if (y1 == s->rects[0]->h) {

         av_freep(&s->rects[0]->pict.data[0]);

         s->rects[0]->w = s->rects[0]->h = 0;

         return 0;
     }
 

     y2 = s->rects[0]->h - 1;

     while (y2 > 0 && is_transp(s->rects[0]->pict.data[0] + y2 * s->rects[0]->pict.linesize[0], 1,

                                s->rects[0]->w, transp_color))

         y2--;
     x1 = 0;

     while (x1 < (s->rects[0]->w - 1) && is_transp(s->rects[0]->pict.data[0] + x1, s->rects[0]->pict.linesize[0],

                                         s->rects[0]->h, transp_color))

         x1++;

     x2 = s->rects[0]->w - 1;

     while (x2 > 0 && is_transp(s->rects[0]->pict.data[0] + x2, s->rects[0]->pict.linesize[0], s->rects[0]->h,

                                   transp_color))
         x2--;
     w = x2 - x1 + 1;
     h = y2 - y1 + 1;
     bitmap = av_malloc(w * h);
     if (!bitmap)
         return 1;
     for(y = 0; y < h; y++) {

         memcpy(bitmap + w * y, s->rects[0]->pict.data[0] + x1 + (y1 + y) * s->rects[0]->pict.linesize[0], w);

     }

     av_freep(&s->rects[0]->pict.data[0]);
     s->rects[0]->pict.data[0] = bitmap;
     s->rects[0]->pict.linesize[0] = w;

     s->rects[0]->w = w;
     s->rects[0]->h = h;
     s->rects[0]->x += x1;
     s->rects[0]->y += y1;

     return 1;
 }
 
 #ifdef DEBUG

 #define ALPHA_MIX(A,BACK,FORE) (((255-(A)) * (BACK) + (A) * (FORE)) / 255)

 static void ppm_save(const char *filename, uint8_t *bitmap, int w, int h,
                      uint32_t *rgba_palette)
 {

     int x, y, alpha;
     uint32_t v;
     int back[3] = {0, 255, 0};  /* green background */

     FILE *f;
 
     f = fopen(filename, "w");
     if (!f) {
         perror(filename);

         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 = rgba_palette[bitmap[y * w + x]];

             alpha = v >> 24;
             putc(ALPHA_MIX(alpha, back[0], (v >> 16) & 0xff), f);
             putc(ALPHA_MIX(alpha, back[1], (v >> 8) & 0xff), f);
             putc(ALPHA_MIX(alpha, back[2], (v >> 0) & 0xff), f);

         }
     }
     fclose(f);
 }
 #endif
 

 static int append_to_cached_buf(AVCodecContext *avctx,
                                 const uint8_t *buf, int buf_size)
 {
     DVDSubContext *ctx = avctx->priv_data;
 

     if (ctx->buf_size >= sizeof(ctx->buf) - buf_size) {

         av_log(avctx, AV_LOG_WARNING, "Attempt to reconstruct "
                "too large SPU packets aborted.\n");
         return AVERROR_INVALIDDATA;
     }
     memcpy(ctx->buf + ctx->buf_size, buf, buf_size);
     ctx->buf_size += buf_size;
     return 0;
 }
 

 static int dvdsub_decode(AVCodecContext *avctx,
                          void *data, int *data_size,

                          AVPacket *avpkt)

 {

     DVDSubContext *ctx = avctx->priv_data;

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

     AVSubtitle *sub = data;

     int is_menu;
 

     if (ctx->buf_size) {

         int ret = append_to_cached_buf(avctx, buf, buf_size);
         if (ret < 0) {
             *data_size = 0;
             return ret;
         }
         buf = ctx->buf;
         buf_size = ctx->buf_size;
     }
 

     is_menu = decode_dvd_subtitles(ctx, sub, buf, buf_size);

     if (is_menu == AVERROR(EAGAIN)) {
         *data_size = 0;
         return append_to_cached_buf(avctx, buf, buf_size);
     }

     if (is_menu < 0) {

     no_subtitle:

         reset_rects(sub);

         *data_size = 0;
 
         return buf_size;
     }

     if (!is_menu && find_smallest_bounding_rectangle(sub) == 0)

         goto no_subtitle;
 

     if (ctx->forced_subs_only && !(sub->rects[0]->flags & AV_SUBTITLE_FLAG_FORCED))
         goto no_subtitle;
 

 #if defined(DEBUG)

     {
     char ppm_name[32];
 
     snprintf(ppm_name, sizeof(ppm_name), "/tmp/%05d.ppm", ctx->sub_id++);

     av_dlog(NULL, "start=%d ms end =%d ms\n",

             sub->start_display_time,
             sub->end_display_time);

     ppm_save(ppm_name, sub->rects[0]->pict.data[0],

              sub->rects[0]->w, sub->rects[0]->h, (uint32_t*) sub->rects[0]->pict.data[1]);

     }

 #endif
 

     ctx->buf_size = 0;

     *data_size = 1;
     return buf_size;
 }
 

 static void parse_palette(DVDSubContext *ctx, char *p)
 {
     int i;
 
     ctx->has_palette = 1;
     for(i=0;i<16;i++) {
         ctx->palette[i] = strtoul(p, &p, 16);

         while(*p == ',' || av_isspace(*p))

             p++;
     }
 }
 

 static int parse_ifo_palette(DVDSubContext *ctx, char *p)
 {
     FILE *ifo;
     char ifostr[12];
     uint32_t sp_pgci, pgci, off_pgc, pgc;
     uint8_t r, g, b, yuv[65], *buf;
     int i, y, cb, cr, r_add, g_add, b_add;
     int ret = 0;
     const uint8_t *cm = ff_crop_tab + MAX_NEG_CROP;
 
     ctx->has_palette = 0;
     if ((ifo = fopen(p, "r")) == NULL) {

         av_log(ctx, AV_LOG_WARNING, "Unable to open IFO file \"%s\": %s\n", p, av_err2str(AVERROR(errno)));

         return AVERROR_EOF;
     }
     if (fread(ifostr, 12, 1, ifo) != 1 || memcmp(ifostr, "DVDVIDEO-VTS", 12)) {
         av_log(ctx, AV_LOG_WARNING, "\"%s\" is not a proper IFO file\n", p);
         ret = AVERROR_INVALIDDATA;
         goto end;
     }

     if (fseek(ifo, 0xCC, SEEK_SET) == -1) {
         ret = AVERROR(errno);
         goto end;
     }

     if (fread(&sp_pgci, 4, 1, ifo) == 1) {
         pgci = av_be2ne32(sp_pgci) * 2048;

         if (fseek(ifo, pgci + 0x0C, SEEK_SET) == -1) {
             ret = AVERROR(errno);
             goto end;
         }

         if (fread(&off_pgc, 4, 1, ifo) == 1) {
             pgc = pgci + av_be2ne32(off_pgc);

             if (fseek(ifo, pgc + 0xA4, SEEK_SET) == -1) {
                 ret = AVERROR(errno);
                 goto end;
             }

             if (fread(yuv, 64, 1, ifo) == 1) {
                 buf = yuv;
                 for(i=0; i<16; i++) {
                     y  = *++buf;
                     cr = *++buf;
                     cb = *++buf;
                     YUV_TO_RGB1_CCIR(cb, cr);
                     YUV_TO_RGB2_CCIR(r, g, b, y);
                     ctx->palette[i] = (r << 16) + (g << 8) + b;
                     buf++;
                 }
                 ctx->has_palette = 1;
             }
         }
     }
     if (ctx->has_palette == 0) {
         av_log(ctx, AV_LOG_WARNING, "Failed to read palette from IFO file \"%s\"\n", p);
         ret = AVERROR_INVALIDDATA;
     }
 end:
     fclose(ifo);
     return ret;
 }
 

 static int dvdsub_parse_extradata(AVCodecContext *avctx)

 {
     DVDSubContext *ctx = (DVDSubContext*) avctx->priv_data;

     char *dataorig, *data;

     int ret = 1;

 
     if (!avctx->extradata || !avctx->extradata_size)
         return 1;
 

     dataorig = data = av_malloc(avctx->extradata_size+1);

     if (!data)
         return AVERROR(ENOMEM);
     memcpy(data, avctx->extradata, avctx->extradata_size);
     data[avctx->extradata_size] = '\0';
 
     for(;;) {
         int pos = strcspn(data, "\n\r");
         if (pos==0 && *data==0)
             break;
 
         if (strncmp("palette:", data, 8) == 0) {

             parse_palette(ctx, data + 8);

         } else if (strncmp("size:", data, 5) == 0) {
             int w, h;

             if (sscanf(data + 5, "%dx%d", &w, &h) == 2) {

                ret = ff_set_dimensions(avctx, w, h);

                if (ret < 0)

                    goto fail;

             }

         }
 
         data += pos;
         data += strspn(data, "\n\r");
     }
 

 fail:

     av_free(dataorig);

     return ret;

 }
 

 static av_cold int dvdsub_init(AVCodecContext *avctx)

 {

     DVDSubContext *ctx = avctx->priv_data;

     int ret;
 
     if ((ret = dvdsub_parse_extradata(avctx)) < 0)
         return ret;
 

     if (ctx->ifo_str)
         parse_ifo_palette(ctx, ctx->ifo_str);

     if (ctx->palette_str)
         parse_palette(ctx, ctx->palette_str);

     if (ctx->has_palette) {
         int i;
         av_log(avctx, AV_LOG_DEBUG, "palette:");
         for(i=0;i<16;i++)
             av_log(avctx, AV_LOG_DEBUG, " 0x%06x", ctx->palette[i]);
         av_log(avctx, AV_LOG_DEBUG, "\n");
     }
 
     return 1;
 }
 

 static av_cold int dvdsub_close(AVCodecContext *avctx)
 {
     DVDSubContext *ctx = avctx->priv_data;
     ctx->buf_size = 0;
     return 0;
 }
 

 #define OFFSET(field) offsetof(DVDSubContext, field)

 #define SD AV_OPT_FLAG_SUBTITLE_PARAM | AV_OPT_FLAG_DECODING_PARAM

 static const AVOption options[] = {

     { "palette", "set the global palette", OFFSET(palette_str), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, SD },

     { "ifo_palette", "obtain the global palette from .IFO file", OFFSET(ifo_str), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, SD },

     { "forced_subs_only", "Only show forced subtitles", OFFSET(forced_subs_only), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, SD},

     { NULL }
 };

 static const AVClass dvdsub_class = {

     .class_name = "dvdsubdec",
     .item_name  = av_default_item_name,
     .option     = options,
     .version    = LIBAVUTIL_VERSION_INT,
 };
 

 AVCodec ff_dvdsub_decoder = {

     .name           = "dvdsub",

     .long_name      = NULL_IF_CONFIG_SMALL("DVD subtitles"),

     .type           = AVMEDIA_TYPE_SUBTITLE,

     .id             = AV_CODEC_ID_DVD_SUBTITLE,

     .priv_data_size = sizeof(DVDSubContext),
     .init           = dvdsub_init,

     .decode         = dvdsub_decode,

     .close          = dvdsub_close,

     .priv_class     = &dvdsub_class,

 };