text: /*
   * DVB subtitle encoding for ffmpeg
   * 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 "bytestream.h"
  #include "colorspace.h"
  
  typedef struct DVBSubtitleContext {
      int hide_state;
      int object_version;
  } DVBSubtitleContext;
  
  #define PUTBITS2(val)\
  {\
      bitbuf |= (val) << bitcnt;\
      bitcnt -= 2;\
      if (bitcnt < 0) {\
          bitcnt = 6;\
          *q++ = bitbuf;\
          bitbuf = 0;\
      }\
  }
  
  static void dvb_encode_rle2(uint8_t **pq,
                              const uint8_t *bitmap, int linesize,
                              int w, int h)
  {
      uint8_t *q;
      unsigned int bitbuf;
      int bitcnt;
      int x, y, len, x1, v, color;
  
      q = *pq;
  
      for(y = 0; y < h; y++) {
          *q++ = 0x10;
          bitbuf = 0;
          bitcnt = 6;
  
          x = 0;
          while (x < w) {
              x1 = x;
              color = bitmap[x1++];
              while (x1 < w && bitmap[x1] == color)
                  x1++;
              len = x1 - x;
              if (color == 0 && len == 2) {
                  PUTBITS2(0);
                  PUTBITS2(0);
                  PUTBITS2(1);
              } else if (len >= 3 && len <= 10) {
                  v = len - 3;
                  PUTBITS2(0);
                  PUTBITS2((v >> 2) | 2);
                  PUTBITS2(v & 3);
                  PUTBITS2(color);
              } else if (len >= 12 && len <= 27) {
                  v = len - 12;
                  PUTBITS2(0);
                  PUTBITS2(0);
                  PUTBITS2(2);
                  PUTBITS2(v >> 2);
                  PUTBITS2(v & 3);
                  PUTBITS2(color);
              } else if (len >= 29) {
                  /* length = 29 ... 284 */
                  if (len > 284)
                      len = 284;
                  v = len - 29;
                  PUTBITS2(0);
                  PUTBITS2(0);
                  PUTBITS2(3);
                  PUTBITS2((v >> 6));
                  PUTBITS2((v >> 4) & 3);
                  PUTBITS2((v >> 2) & 3);
                  PUTBITS2(v & 3);
                  PUTBITS2(color);
              } else {
                  PUTBITS2(color);
                  if (color == 0) {
                      PUTBITS2(1);
                  }
                  len = 1;
              }
              x += len;
          }
          /* end of line */
          PUTBITS2(0);
          PUTBITS2(0);
          PUTBITS2(0);
          if (bitcnt != 6) {
              *q++ = bitbuf;
          }
          *q++ = 0xf0;
          bitmap += linesize;
      }
      *pq = q;
  }
  
  #define PUTBITS4(val)\
  {\
      bitbuf |= (val) << bitcnt;\
      bitcnt -= 4;\
      if (bitcnt < 0) {\
          bitcnt = 4;\
          *q++ = bitbuf;\
          bitbuf = 0;\
      }\
  }
  
  /* some DVB decoders only implement 4 bits/pixel */
  static void dvb_encode_rle4(uint8_t **pq,
                              const uint8_t *bitmap, int linesize,
                              int w, int h)
  {
      uint8_t *q;
      unsigned int bitbuf;
      int bitcnt;
      int x, y, len, x1, v, color;
  
      q = *pq;
  
      for(y = 0; y < h; y++) {
          *q++ = 0x11;
          bitbuf = 0;
          bitcnt = 4;
  
          x = 0;
          while (x < w) {
              x1 = x;
              color = bitmap[x1++];
              while (x1 < w && bitmap[x1] == color)
                  x1++;
              len = x1 - x;
              if (color == 0 && len == 2) {
                  PUTBITS4(0);
                  PUTBITS4(0xd);
              } else if (color == 0 && (len >= 3 && len <= 9)) {
                  PUTBITS4(0);
                  PUTBITS4(len - 2);
              } else if (len >= 4 && len <= 7) {
                  PUTBITS4(0);
                  PUTBITS4(8 + len - 4);
                  PUTBITS4(color);
              } else if (len >= 9 && len <= 24) {
                  PUTBITS4(0);
                  PUTBITS4(0xe);
                  PUTBITS4(len - 9);
                  PUTBITS4(color);
              } else if (len >= 25) {
                  if (len > 280)
                      len = 280;
                  v = len - 25;
                  PUTBITS4(0);
                  PUTBITS4(0xf);
                  PUTBITS4(v >> 4);
                  PUTBITS4(v & 0xf);
                  PUTBITS4(color);
              } else {
                  PUTBITS4(color);
                  if (color == 0) {
                      PUTBITS4(0xc);
                  }
                  len = 1;
              }
              x += len;
          }
          /* end of line */
          PUTBITS4(0);
          PUTBITS4(0);
          if (bitcnt != 4) {
              *q++ = bitbuf;
          }
          *q++ = 0xf0;
          bitmap += linesize;
      }
      *pq = q;
  }
  
  static int encode_dvb_subtitles(DVBSubtitleContext *s,
                                  uint8_t *outbuf, AVSubtitle *h)
  {
      uint8_t *q, *pseg_len;
      int page_id, region_id, clut_id, object_id, i, bpp_index, page_state;
  
  
      q = outbuf;
  
      page_id = 1;
  
      if (h->num_rects == 0 || h->rects == NULL)
          return -1;
  
      *q++ = 0x00; /* subtitle_stream_id */
  
      /* page composition segment */
  
      *q++ = 0x0f; /* sync_byte */
      *q++ = 0x10; /* segment_type */
      bytestream_put_be16(&q, page_id);
      pseg_len = q;
      q += 2; /* segment length */
      *q++ = 30; /* page_timeout (seconds) */
      if (s->hide_state)
          page_state = 0; /* normal case */
      else
          page_state = 2; /* mode change */
      /* page_version = 0 + page_state */
      *q++ = s->object_version | (page_state << 2) | 3;
  
      for (region_id = 0; region_id < h->num_rects; region_id++) {
          *q++ = region_id;
          *q++ = 0xff; /* reserved */
          bytestream_put_be16(&q, h->rects[region_id]->x); /* left pos */
          bytestream_put_be16(&q, h->rects[region_id]->y); /* top pos */
      }
  
      bytestream_put_be16(&pseg_len, q - pseg_len - 2);
  
      if (!s->hide_state) {
          for (clut_id = 0; clut_id < h->num_rects; clut_id++) {
  
              /* CLUT segment */
  
              if (h->rects[clut_id]->nb_colors <= 4) {
                  /* 2 bpp, some decoders do not support it correctly */
                  bpp_index = 0;
              } else if (h->rects[clut_id]->nb_colors <= 16) {
                  /* 4 bpp, standard encoding */
                  bpp_index = 1;
              } else {
                  return -1;
              }
  
              *q++ = 0x0f; /* sync byte */
              *q++ = 0x12; /* CLUT definition segment */
              bytestream_put_be16(&q, page_id);
              pseg_len = q;
              q += 2; /* segment length */
              *q++ = clut_id;
              *q++ = (0 << 4) | 0xf; /* version = 0 */
  
              for(i = 0; i < h->rects[clut_id]->nb_colors; i++) {
                  *q++ = i; /* clut_entry_id */
                  *q++ = (1 << (7 - bpp_index)) | (0xf << 1) | 1; /* 2 bits/pixel full range */
                  {
                      int a, r, g, b;
                      uint32_t x= ((uint32_t*)h->rects[clut_id]->pict.data[1])[i];
                      a = (x >> 24) & 0xff;
                      r = (x >> 16) & 0xff;
                      g = (x >>  8) & 0xff;
                      b = (x >>  0) & 0xff;
  
                      *q++ = RGB_TO_Y_CCIR(r, g, b);
                      *q++ = RGB_TO_V_CCIR(r, g, b, 0);
                      *q++ = RGB_TO_U_CCIR(r, g, b, 0);
                      *q++ = 255 - a;
                  }
              }
  
              bytestream_put_be16(&pseg_len, q - pseg_len - 2);
          }
      }
  
      for (region_id = 0; region_id < h->num_rects; region_id++) {
  
          /* region composition segment */
  
          if (h->rects[region_id]->nb_colors <= 4) {
              /* 2 bpp, some decoders do not support it correctly */
              bpp_index = 0;
          } else if (h->rects[region_id]->nb_colors <= 16) {
              /* 4 bpp, standard encoding */
              bpp_index = 1;
          } else {
              return -1;
          }
  
          *q++ = 0x0f; /* sync_byte */
          *q++ = 0x11; /* segment_type */
          bytestream_put_be16(&q, page_id);
          pseg_len = q;
          q += 2; /* segment length */
          *q++ = region_id;
          *q++ = (s->object_version << 4) | (0 << 3) | 0x07; /* version , no fill */
          bytestream_put_be16(&q, h->rects[region_id]->w); /* region width */
          bytestream_put_be16(&q, h->rects[region_id]->h); /* region height */
          *q++ = ((1 + bpp_index) << 5) | ((1 + bpp_index) << 2) | 0x03;
          *q++ = region_id; /* clut_id == region_id */
          *q++ = 0; /* 8 bit fill colors */
          *q++ = 0x03; /* 4 bit and 2 bit fill colors */
  
          if (!s->hide_state) {
              bytestream_put_be16(&q, region_id); /* object_id == region_id */
              *q++ = (0 << 6) | (0 << 4);
              *q++ = 0;
              *q++ = 0xf0;
              *q++ = 0;
          }
  
          bytestream_put_be16(&pseg_len, q - pseg_len - 2);
      }
  
      if (!s->hide_state) {
  
          for (object_id = 0; object_id < h->num_rects; object_id++) {
              /* Object Data segment */
  
              if (h->rects[object_id]->nb_colors <= 4) {
                  /* 2 bpp, some decoders do not support it correctly */
                  bpp_index = 0;
              } else if (h->rects[object_id]->nb_colors <= 16) {
                  /* 4 bpp, standard encoding */
                  bpp_index = 1;
              } else {
                  return -1;
              }
  
              *q++ = 0x0f; /* sync byte */
              *q++ = 0x13;
              bytestream_put_be16(&q, page_id);
              pseg_len = q;
              q += 2; /* segment length */
  
              bytestream_put_be16(&q, object_id);
              *q++ = (s->object_version << 4) | (0 << 2) | (0 << 1) | 1; /* version = 0,
                                                                         onject_coding_method,
                                                                         non_modifying_color_flag */
              {
                  uint8_t *ptop_field_len, *pbottom_field_len, *top_ptr, *bottom_ptr;
                  void (*dvb_encode_rle)(uint8_t **pq,
                                          const uint8_t *bitmap, int linesize,
                                          int w, int h);
                  ptop_field_len = q;
                  q += 2;
                  pbottom_field_len = q;
                  q += 2;
  
                  if (bpp_index == 0)
                      dvb_encode_rle = dvb_encode_rle2;
                  else
                      dvb_encode_rle = dvb_encode_rle4;
  
                  top_ptr = q;
                  dvb_encode_rle(&q, h->rects[object_id]->pict.data[0], h->rects[object_id]->w * 2,
                                      h->rects[object_id]->w, h->rects[object_id]->h >> 1);
                  bottom_ptr = q;
                  dvb_encode_rle(&q, h->rects[object_id]->pict.data[0] + h->rects[object_id]->w,
                                      h->rects[object_id]->w * 2, h->rects[object_id]->w,
                                      h->rects[object_id]->h >> 1);
  
                  bytestream_put_be16(&ptop_field_len, bottom_ptr - top_ptr);
                  bytestream_put_be16(&pbottom_field_len, q - bottom_ptr);
              }
  
              bytestream_put_be16(&pseg_len, q - pseg_len - 2);
          }
      }
  
      /* end of display set segment */
  
      *q++ = 0x0f; /* sync_byte */
      *q++ = 0x80; /* segment_type */
      bytestream_put_be16(&q, page_id);
      pseg_len = q;
      q += 2; /* segment length */
  
      bytestream_put_be16(&pseg_len, q - pseg_len - 2);
  
      *q++ = 0xff; /* end of PES data */
  
      s->object_version = (s->object_version + 1) & 0xf;
      s->hide_state = !s->hide_state;
      return q - outbuf;
  }
  
  static int dvbsub_encode(AVCodecContext *avctx,
                         unsigned char *buf, int buf_size, void *data)
  {
      DVBSubtitleContext *s = avctx->priv_data;
      AVSubtitle *sub = data;
      int ret;
  
      ret = encode_dvb_subtitles(s, buf, sub);
      return ret;
  }
  
  AVCodec dvbsub_encoder = {
      "dvbsub",
      AVMEDIA_TYPE_SUBTITLE,
      CODEC_ID_DVB_SUBTITLE,
      sizeof(DVBSubtitleContext),
      NULL,
      dvbsub_encode,
      .long_name = NULL_IF_CONFIG_SMALL("DVB subtitles"),
  };
  