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FFmpeg/libavcodec/ccaption_dec.c

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  1. /*

  2.  * Closed Caption Decoding

  3.  * Copyright (c) 2015 Anshul Maheshwari

  4.  *

  5.  * This file is part of FFmpeg.

  6.  *

  7.  * FFmpeg is free software; you can redistribute it and/or

  8.  * modify it under the terms of the GNU Lesser General Public

  9.  * License as published by the Free Software Foundation; either

  10.  * version 2.1 of the License, or (at your option) any later version.

  11.  *

  12.  * FFmpeg is distributed in the hope that it will be useful,

  13.  * but WITHOUT ANY WARRANTY; without even the implied warranty of

  14.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

  15.  * Lesser General Public License for more details.

  16.  *

  17.  * You should have received a copy of the GNU Lesser General Public

  18.  * License along with FFmpeg; if not, write to the Free Software

  19.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

  20.  */

  21. 

  22. #include "avcodec.h"

  23. #include "ass.h"

  24. #include "libavutil/opt.h"

  25. 

  26. #define CHAR_DEBUG

  27. #define SCREEN_ROWS 15

  28. #define SCREEN_COLUMNS 32

  29. 

  30. #define SET_FLAG(var, val) ( var |= ( 1 << (val) ) )

  31. #define UNSET_FLAG(var, val) ( var &=  ~( 1 << (val)) )

  32. #define CHECK_FLAG(var, val) ( (var) & (1 << (val) ) )

  33. 

  34. /*

  35.  * TODO list

  36.  * 1) handle font and color completely

  37.  */

  38. enum cc_mode {

  39.     CCMODE_POPON,

  40.     CCMODE_PAINTON,

  41.     CCMODE_ROLLUP_2,

  42.     CCMODE_ROLLUP_3,

  43.     CCMODE_ROLLUP_4,

  44.     CCMODE_TEXT,

  45. };

  46. 

  47. enum cc_color_code

  48. {

  49.     CCCOL_WHITE,

  50.     CCCOL_GREEN,

  51.     CCCOL_BLUE,

  52.     CCCOL_CYAN,

  53.     CCCOL_RED,

  54.     CCCOL_YELLOW,

  55.     CCCOL_MAGENTA,

  56.     CCCOL_USERDEFINED,

  57.     CCCOL_BLACK,

  58.     CCCOL_TRANSPARENT

  59. };

  60. 

  61. enum cc_font

  62. {

  63.     CCFONT_REGULAR,

  64.     CCFONT_ITALICS,

  65.     CCFONT_UNDERLINED,

  66.     CCFONT_UNDERLINED_ITALICS

  67. };

  68. 

  69. static const unsigned char pac2_attribs[][3] = // Color, font, ident

  70. {

  71.     { CCCOL_WHITE, CCFONT_REGULAR, 0 },  // 0x40 || 0x60

  72.     { CCCOL_WHITE, CCFONT_UNDERLINED, 0 },  // 0x41 || 0x61

  73.     { CCCOL_GREEN, CCFONT_REGULAR, 0 },  // 0x42 || 0x62

  74.     { CCCOL_GREEN, CCFONT_UNDERLINED, 0 },  // 0x43 || 0x63

  75.     { CCCOL_BLUE, CCFONT_REGULAR, 0 },  // 0x44 || 0x64

  76.     { CCCOL_BLUE, CCFONT_UNDERLINED, 0 },  // 0x45 || 0x65

  77.     { CCCOL_CYAN, CCFONT_REGULAR, 0 },  // 0x46 || 0x66

  78.     { CCCOL_CYAN, CCFONT_UNDERLINED, 0 },  // 0x47 || 0x67

  79.     { CCCOL_RED, CCFONT_REGULAR, 0 },  // 0x48 || 0x68

  80.     { CCCOL_RED, CCFONT_UNDERLINED, 0 },  // 0x49 || 0x69

  81.     { CCCOL_YELLOW, CCFONT_REGULAR, 0 },  // 0x4a || 0x6a

  82.     { CCCOL_YELLOW, CCFONT_UNDERLINED, 0 },  // 0x4b || 0x6b

  83.     { CCCOL_MAGENTA, CCFONT_REGULAR, 0 },  // 0x4c || 0x6c

  84.     { CCCOL_MAGENTA, CCFONT_UNDERLINED, 0 },  // 0x4d || 0x6d

  85.     { CCCOL_WHITE, CCFONT_ITALICS, 0 },  // 0x4e || 0x6e

  86.     { CCCOL_WHITE, CCFONT_UNDERLINED_ITALICS, 0 },  // 0x4f || 0x6f

  87.     { CCCOL_WHITE, CCFONT_REGULAR, 0 },  // 0x50 || 0x70

  88.     { CCCOL_WHITE, CCFONT_UNDERLINED, 0 },  // 0x51 || 0x71

  89.     { CCCOL_WHITE, CCFONT_REGULAR, 4 },  // 0x52 || 0x72

  90.     { CCCOL_WHITE, CCFONT_UNDERLINED, 4 },  // 0x53 || 0x73

  91.     { CCCOL_WHITE, CCFONT_REGULAR, 8 },  // 0x54 || 0x74

  92.     { CCCOL_WHITE, CCFONT_UNDERLINED, 8 },  // 0x55 || 0x75

  93.     { CCCOL_WHITE, CCFONT_REGULAR, 12 }, // 0x56 || 0x76

  94.     { CCCOL_WHITE, CCFONT_UNDERLINED, 12 }, // 0x57 || 0x77

  95.     { CCCOL_WHITE, CCFONT_REGULAR, 16 }, // 0x58 || 0x78

  96.     { CCCOL_WHITE, CCFONT_UNDERLINED, 16 }, // 0x59 || 0x79

  97.     { CCCOL_WHITE, CCFONT_REGULAR, 20 }, // 0x5a || 0x7a

  98.     { CCCOL_WHITE, CCFONT_UNDERLINED, 20 }, // 0x5b || 0x7b

  99.     { CCCOL_WHITE, CCFONT_REGULAR, 24 }, // 0x5c || 0x7c

  100.     { CCCOL_WHITE, CCFONT_UNDERLINED, 24 }, // 0x5d || 0x7d

  101.     { CCCOL_WHITE, CCFONT_REGULAR, 28 }, // 0x5e || 0x7e

  102.     { CCCOL_WHITE, CCFONT_UNDERLINED, 28 }  // 0x5f || 0x7f

  103.     /* total 32 entry */

  104. };

  105. /* 0-255 needs 256 space */

  106. static const uint8_t parity_table[256] = { 0, 1, 1, 0, 1, 0, 0, 1,

  107.                                            1, 0, 0, 1, 0, 1, 1, 0,

  108.                                            1, 0, 0, 1, 0, 1, 1, 0,

  109.                                            0, 1, 1, 0, 1, 0, 0, 1,

  110.                                            1, 0, 0, 1, 0, 1, 1, 0,

  111.                                            0, 1, 1, 0, 1, 0, 0, 1,

  112.                                            0, 1, 1, 0, 1, 0, 0, 1,

  113.                                            1, 0, 0, 1, 0, 1, 1, 0,

  114.                                            1, 0, 0, 1, 0, 1, 1, 0,

  115.                                            0, 1, 1, 0, 1, 0, 0, 1,

  116.                                            0, 1, 1, 0, 1, 0, 0, 1,

  117.                                            1, 0, 0, 1, 0, 1, 1, 0,

  118.                                            0, 1, 1, 0, 1, 0, 0, 1,

  119.                                            1, 0, 0, 1, 0, 1, 1, 0,

  120.                                            1, 0, 0, 1, 0, 1, 1, 0,

  121.                                            0, 1, 1, 0, 1, 0, 0, 1,

  122.                                            1, 0, 0, 1, 0, 1, 1, 0,

  123.                                            0, 1, 1, 0, 1, 0, 0, 1,

  124.                                            0, 1, 1, 0, 1, 0, 0, 1,

  125.                                            1, 0, 0, 1, 0, 1, 1, 0,

  126.                                            0, 1, 1, 0, 1, 0, 0, 1,

  127.                                            1, 0, 0, 1, 0, 1, 1, 0,

  128.                                            1, 0, 0, 1, 0, 1, 1, 0,

  129.                                            0, 1, 1, 0, 1, 0, 0, 1,

  130.                                            0, 1, 1, 0, 1, 0, 0, 1,

  131.                                            1, 0, 0, 1, 0, 1, 1, 0,

  132.                                            1, 0, 0, 1, 0, 1, 1, 0,

  133.                                            0, 1, 1, 0, 1, 0, 0, 1,

  134.                                            1, 0, 0, 1, 0, 1, 1, 0,

  135.                                            0, 1, 1, 0, 1, 0, 0, 1,

  136.                                            0, 1, 1, 0, 1, 0, 0, 1,

  137.                                            1, 0, 0, 1, 0, 1, 1, 0 };

  138. struct Screen {

  139.     /* +1 is used to compensate null character of string */

  140.     uint8_t characters[SCREEN_ROWS][SCREEN_COLUMNS+1];

  141.     /*

  142.      * Bitmask of used rows; if a bit is not set, the

  143.      * corresponding row is not used.

  144.      * for setting row 1  use row | (0 << 1)

  145.      * for setting row 15 use row | (1 << 14)

  146.      */

  147.     int16_t  row_used;

  148. };

  149. 

  150. 

  151. typedef struct CCaptionSubContext {

  152.     AVClass *class;

  153.     int row_cnt;

  154.     struct Screen screen[2];

  155.     int active_screen;

  156.     uint8_t cursor_row;

  157.     uint8_t cursor_column;

  158.     uint8_t cursor_color;

  159.     uint8_t cursor_font;

  160.     AVBPrint buffer;

  161.     int erase_display_memory;

  162.     int rollup;

  163.     enum  cc_mode mode;

  164.     int64_t start_time;

  165.     /* visible screen time */

  166.     int64_t startv_time;

  167.     int64_t end_time;

  168.     char prev_cmd[2];

  169.     /* buffer to store pkt data */

  170.     AVBufferRef *pktbuf;

  171. }CCaptionSubContext;

  172. 

  173. 

  174. static av_cold int init_decoder(AVCodecContext *avctx)

  175. {

  176.     int ret;

  177.     CCaptionSubContext *ctx = avctx->priv_data;

  178. 

  179.     av_bprint_init(&ctx->buffer, 0, AV_BPRINT_SIZE_UNLIMITED);

  180.     /* taking by default roll up to 2 */

  181.     ctx->rollup = 2;

  182.     ret = ff_ass_subtitle_header_default(avctx);

  183.     /* allocate pkt buffer */

  184.     ctx->pktbuf = av_buffer_alloc(128);

  185.     if( !ctx->pktbuf) {

  186.         ret = AVERROR(ENOMEM);

  187.     }

  188. 

  189. 

  190.     return ret;

  191. }

  192. 

  193. static av_cold int close_decoder(AVCodecContext *avctx)

  194. {

  195.     CCaptionSubContext *ctx = avctx->priv_data;

  196.     av_bprint_finalize( &ctx->buffer, NULL);

  197.     av_buffer_unref(&ctx->pktbuf);

  198.     return 0;

  199. }

  200. /**

  201.  * @param ctx closed caption context just to print log

  202.  */

  203. static int write_char (CCaptionSubContext *ctx, char *row,uint8_t col, char ch)

  204. {

  205.     if(col < SCREEN_COLUMNS) {

  206.         row[col] = ch;

  207.         return 0;

  208.     }

  209.     /* We have extra space at end only for null character */

  210.     else if ( col == SCREEN_COLUMNS && ch == 0) {

  211.         row[col] = ch;

  212.         return 0;

  213.     }

  214.     else {

  215.         av_log(ctx, AV_LOG_WARNING,"Data Ignored since exciding screen width\n");

  216.         return AVERROR_INVALIDDATA;

  217.     }

  218. }

  219. /**

  220.  * This function after validating parity bit, also remove it from data pair.

  221.  * The first byte doesn't pass parity, we replace it with a solid blank

  222.  * and process the pair.

  223.  * If the second byte doesn't pass parity, it returns INVALIDDATA

  224.  * user can ignore the whole pair and pass the other pair.

  225.  */

  226. static int validate_cc_data_pair (uint8_t *cc_data_pair)

  227. {

  228.     uint8_t cc_valid = (*cc_data_pair & 4) >>2;

  229.     uint8_t cc_type = *cc_data_pair & 3;

  230. 

  231.     if (!cc_valid)

  232.         return AVERROR_INVALIDDATA;

  233. 

  234.     // if EIA-608 data then verify parity.

  235.     if (cc_type==0 || cc_type==1) {

  236.         if (!parity_table[cc_data_pair[2]]) {

  237.             return AVERROR_INVALIDDATA;

  238.         }

  239.         if (!parity_table[cc_data_pair[1]]) {

  240.             cc_data_pair[1]=0x7F;

  241.         }

  242.     }

  243. 

  244.     //Skip non-data

  245.     if( (cc_data_pair[0] == 0xFA || cc_data_pair[0] == 0xFC || cc_data_pair[0] == 0xFD )

  246.          && (cc_data_pair[1] & 0x7F) == 0 && (cc_data_pair[2] & 0x7F) == 0)

  247.         return AVERROR_PATCHWELCOME;

  248. 

  249.     //skip 708 data

  250.     if(cc_type == 3 || cc_type == 2 )

  251.         return AVERROR_PATCHWELCOME;

  252. 

  253.     /* remove parity bit */

  254.     cc_data_pair[1] &= 0x7F;

  255.     cc_data_pair[2] &= 0x7F;

  256. 

  257. 

  258.     return 0;

  259. 

  260. }

  261. 

  262. static struct Screen *get_writing_screen(CCaptionSubContext *ctx)

  263. {

  264.     switch (ctx->mode) {

  265.     case CCMODE_POPON:

  266.         // use Inactive screen

  267.         return ctx->screen + !ctx->active_screen;

  268.     case CCMODE_PAINTON:

  269.     case CCMODE_ROLLUP_2:

  270.     case CCMODE_ROLLUP_3:

  271.     case CCMODE_ROLLUP_4:

  272.     case CCMODE_TEXT:

  273.         // use active screen

  274.         return ctx->screen + ctx->active_screen;

  275.     }

  276.     /* It was never an option */

  277.     return NULL;

  278. }

  279. 

  280. static void handle_textattr( CCaptionSubContext *ctx, uint8_t hi, uint8_t lo )

  281. {

  282.     int i = lo - 0x20;

  283.     int ret;

  284.     struct Screen *screen = get_writing_screen(ctx);

  285.     char *row = screen->characters[ctx->cursor_row];

  286. 

  287.     if( i >= 32)

  288.         return;

  289. 

  290.     ctx->cursor_color =  pac2_attribs[i][0];

  291.     ctx->cursor_font = pac2_attribs[i][1];

  292. 

  293.     SET_FLAG(screen->row_used,ctx->cursor_row);

  294.     ret = write_char(ctx, row, ctx->cursor_column, ' ');

  295.     if(ret == 0)

  296.         ctx->cursor_column++;

  297. }

  298. static void handle_pac( CCaptionSubContext *ctx, uint8_t hi, uint8_t lo )

  299. {

  300.     static const int8_t row_map[] = {

  301.         11, -1, 1, 2, 3, 4, 12, 13, 14, 15, 5, 6, 7, 8, 9, 10

  302.     };

  303.     const int index = ( (hi<<1) & 0x0e) | ( (lo>>5) & 0x01 );

  304.     struct Screen *screen = get_writing_screen(ctx);

  305.     char *row;

  306.     int indent,i,ret;

  307. 

  308.     if( row_map[index] <= 0 )

  309.         return;

  310. 

  311.     lo &= 0x1f;

  312. 

  313.     ctx->cursor_row = row_map[index] - 1;

  314.     ctx->cursor_color =  pac2_attribs[lo][0];

  315.     ctx->cursor_font = pac2_attribs[lo][1];

  316.     ctx->cursor_column = 0;

  317.     indent = pac2_attribs[lo][2];

  318.     row = screen->characters[ctx->cursor_row];

  319.     for(i = 0;i < indent; i++) {

  320.         ret = write_char(ctx, row, ctx->cursor_column, ' ');

  321.         if(  ret == 0 )

  322.             ctx->cursor_column++;

  323.     }

  324. 

  325. }

  326. 

  327. /**

  328.  * @param pts it is required to set end time

  329.  */

  330. static int handle_edm(CCaptionSubContext *ctx,int64_t pts)

  331. {

  332.     int i;

  333.     int ret = 0;

  334.     struct Screen *screen = ctx->screen + ctx->active_screen;

  335. 

  336.     ctx->start_time = ctx->startv_time;

  337.     for( i = 0; screen->row_used && i < SCREEN_ROWS; i++)

  338.     {

  339.         if(CHECK_FLAG(screen->row_used,i)) {

  340.             char *str = screen->characters[i];

  341.             /* skip space */

  342.             while (*str == ' ')

  343.                 str++;

  344.             av_bprint_append_data(&ctx->buffer, str, strlen(str));

  345.             av_bprint_append_data(&ctx->buffer, "\\N",2);

  346.             UNSET_FLAG(screen->row_used, i);

  347.             ret = av_bprint_is_complete(&ctx->buffer);

  348.             if( ret == 0) {

  349.                 ret = AVERROR(ENOMEM);

  350.                 break;

  351.             }

  352.         }

  353. 

  354.     }

  355.     ctx->startv_time = pts;

  356.     ctx->erase_display_memory = 1;

  357.     ctx->end_time = pts;

  358.     return ret;

  359. }

  360. static int handle_eoc(CCaptionSubContext *ctx, int64_t pts)

  361. {

  362.     int ret;

  363.     ret = handle_edm(ctx,pts);

  364.     ctx->active_screen = !ctx->active_screen;

  365.     ctx->cursor_column = 0;

  366.     return ret;

  367. }

  368. static void handle_delete_end_of_row( CCaptionSubContext *ctx, char hi, char lo)

  369. {

  370.     struct Screen *screen = get_writing_screen(ctx);

  371.     char *row = screen->characters[ctx->cursor_row];

  372.     write_char(ctx, row, ctx->cursor_column, 0);

  373. 

  374. }

  375. static void handle_char(CCaptionSubContext *ctx, char hi, char lo, int64_t pts)

  376. {

  377.     struct Screen *screen = get_writing_screen(ctx);

  378.     char *row = screen->characters[ctx->cursor_row];

  379.     int ret;

  380. 

  381.     SET_FLAG(screen->row_used,ctx->cursor_row);

  382. 

  383.     ret = write_char(ctx, row, ctx->cursor_column, hi);

  384.     if( ret == 0 )

  385.         ctx->cursor_column++;

  386. 

  387.     if(lo) {

  388.         ret = write_char(ctx, row, ctx->cursor_column, lo);

  389.         if ( ret == 0 )

  390.             ctx->cursor_column++;

  391.     }

  392.     write_char(ctx, row, ctx->cursor_column, 0);

  393. 

  394.     /* reset prev command since character can repeat */

  395.     ctx->prev_cmd[0] = 0;

  396.     ctx->prev_cmd[1] = 0;

  397. #ifdef CHAR_DEBUG

  398.     av_log(ctx, AV_LOG_DEBUG,"(%c,%c)\n",hi,lo);

  399. #endif

  400. }

  401. static int process_cc608(CCaptionSubContext *ctx, int64_t pts, uint8_t hi, uint8_t lo)

  402. {

  403.     int ret = 0;

  404. #define COR3(var, with1, with2, with3)  ( (var) == (with1) ||  (var) == (with2) || (var) == (with3) )

  405.     if ( hi == ctx->prev_cmd[0] && lo == ctx->prev_cmd[1]) {

  406.     /* ignore redundant command */

  407.     } else if ( (hi == 0x10 && (lo >= 0x40 || lo <= 0x5f)) ||

  408.               ( (hi >= 0x11 && hi <= 0x17) && (lo >= 0x40 && lo <= 0x7f) ) ) {

  409.         handle_pac(ctx, hi, lo);

  410.     } else if ( ( hi == 0x11 && lo >= 0x20 && lo <= 0x2f ) ||

  411.                 ( hi == 0x17 && lo >= 0x2e && lo <= 0x2f) ) {

  412.         handle_textattr(ctx, hi, lo);

  413.     } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x20 ) {

  414.     /* resume caption loading */

  415.         ctx->mode = CCMODE_POPON;

  416.     } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x24 ) {

  417.         handle_delete_end_of_row(ctx, hi, lo);

  418.     } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x25 ) {

  419.         ctx->rollup = 2;

  420.     } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x26 ) {

  421.         ctx->rollup = 3;

  422.     } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x27 ) {

  423.         ctx->rollup = 4;

  424.     } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x29 ) {

  425.     /* resume direct captioning */

  426.         ctx->mode = CCMODE_PAINTON;

  427.     } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x2B ) {

  428.     /* resume text display */

  429.         ctx->mode = CCMODE_TEXT;

  430.     } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x2C ) {

  431.     /* erase display memory */

  432.         ret = handle_edm(ctx, pts);

  433.     } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x2D ) {

  434.     /* carriage return */

  435.         ctx->row_cnt++;

  436.         if(ctx->row_cnt >= ctx->rollup) {

  437.             ctx->row_cnt = 0;

  438.             ret = handle_edm(ctx, pts);

  439.             ctx->active_screen = !ctx->active_screen;

  440.         }

  441.         ctx->cursor_column = 0;

  442.     } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x2F ) {

  443.     /* end of caption */

  444.         ret = handle_eoc(ctx, pts);

  445.     } else if (hi>=0x20) {

  446.     /* Standard characters (always in pairs) */

  447.         handle_char(ctx, hi, lo, pts);

  448.     } else {

  449.     /* Ignoring all other non data code */

  450.     }

  451. 

  452.     /* set prev command */

  453.      ctx->prev_cmd[0] = hi;

  454.      ctx->prev_cmd[1] = lo;

  455. 

  456. #undef COR3

  457.     return ret;

  458. 

  459. }

  460. static int decode(AVCodecContext *avctx, void *data, int *got_sub, AVPacket *avpkt)

  461. {

  462.     CCaptionSubContext *ctx = avctx->priv_data;

  463.     AVSubtitle *sub = data;

  464.     uint8_t *bptr = NULL;

  465.     int len = avpkt->size;

  466.     int ret = 0;

  467.     int i;

  468. 

  469.     if ( ctx->pktbuf->size < len) {

  470.         ret = av_buffer_realloc(&ctx->pktbuf, len);

  471.          if(ret < 0) {

  472.             av_log(ctx, AV_LOG_WARNING, "Insufficient Memory of %d truncated to %d\n",len, ctx->pktbuf->size);

  473.             len = ctx->pktbuf->size;

  474.             ret = 0;

  475.         }

  476.     }

  477.     memcpy(ctx->pktbuf->data, avpkt->data, len);

  478.     bptr = ctx->pktbuf->data;

  479. 

  480. 

  481.     for (i  = 0; i < len; i += 3) {

  482.         uint8_t cc_type = *(bptr + i) & 3;

  483.         if (validate_cc_data_pair( bptr + i) )

  484.             continue;

  485.         /* ignoring data field 1 */

  486.         if(cc_type == 1)

  487.             continue;

  488.         else

  489.             process_cc608(ctx, avpkt->pts, *(bptr + i + 1) & 0x7f, *(bptr + i + 2) & 0x7f);

  490.         if(ctx->erase_display_memory && *ctx->buffer.str)

  491.         {

  492.             int start_time = av_rescale_q(ctx->start_time, avctx->time_base, (AVRational){ 1, 100 });

  493.             int end_time = av_rescale_q(ctx->end_time, avctx->time_base, (AVRational){ 1, 100 });

  494. #ifdef CHAR_DEBUG

  495.             av_log(ctx, AV_LOG_DEBUG,"cdp writing data (%s)\n",ctx->buffer.str);

  496. #endif

  497.             ret = ff_ass_add_rect(sub, ctx->buffer.str, start_time, end_time - start_time , 0);

  498.             if (ret < 0)

  499.                 return ret;

  500.             sub->pts = av_rescale_q(ctx->start_time, avctx->time_base, AV_TIME_BASE_Q);

  501.             ctx->erase_display_memory = 0;

  502.             av_bprint_clear(&ctx->buffer);

  503.         }

  504.     }

  505. 

  506.     *got_sub = sub->num_rects > 0;

  507.     return ret;

  508. }

  509. static const AVOption options[] = {

  510.     {NULL}

  511. };

  512. static const AVClass ccaption_dec_class = {

  513.     .class_name = "Closed caption Decoder",

  514.     .item_name  = av_default_item_name,

  515.     .option     = options,

  516.     .version    = LIBAVUTIL_VERSION_INT,

  517. };

  518. 

  519. AVCodec ff_ccaption_decoder = {

  520.     .name           = "cc_dec",

  521.     .long_name      = NULL_IF_CONFIG_SMALL("Closed Caption (EIA-608 / CEA-708) Decoder"),

  522.     .type           = AVMEDIA_TYPE_SUBTITLE,

  523.     .id             = AV_CODEC_ID_EIA_608,

  524.     .priv_data_size = sizeof(CCaptionSubContext),

  525.     .init           = init_decoder,

  526.     .close          = close_decoder,

  527.     .decode         = decode,

  528.     .priv_class     = &ccaption_dec_class,

  529. };