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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/internal.h"

  25. #include "libavutil/opt.h"

  26. 

  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.     CCCOL_WHITE,

  49.     CCCOL_GREEN,

  50.     CCCOL_BLUE,

  51.     CCCOL_CYAN,

  52.     CCCOL_RED,

  53.     CCCOL_YELLOW,

  54.     CCCOL_MAGENTA,

  55.     CCCOL_USERDEFINED,

  56.     CCCOL_BLACK,

  57.     CCCOL_TRANSPARENT,

  58. };

  59. 

  60. enum cc_font {

  61.     CCFONT_REGULAR,

  62.     CCFONT_ITALICS,

  63.     CCFONT_UNDERLINED,

  64.     CCFONT_UNDERLINED_ITALICS,

  65. };

  66. 

  67. static const unsigned char pac2_attribs[32][3] = // Color, font, ident

  68. {

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  101.     /* total 32 entries */

  102. };

  103. 

  104. /* 0-255 needs 256 spaces */

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

  106.                                            1, 0, 0, 1, 0, 1, 1, 0,

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  136.                                            1, 0, 0, 1, 0, 1, 1, 0 };

  137. 

  138. struct Screen {

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

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

  141.     uint8_t colors[SCREEN_ROWS+1][SCREEN_COLUMNS+1];

  142.     uint8_t fonts[SCREEN_ROWS+1][SCREEN_COLUMNS+1];

  143.     /*

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

  145.      * corresponding row is not used.

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

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

  148.      */

  149.     int16_t  row_used;

  150. };

  151. 

  152. 

  153. typedef struct CCaptionSubContext {

  154.     AVClass *class;

  155.     struct Screen screen[2];

  156.     int active_screen;

  157.     uint8_t cursor_row;

  158.     uint8_t cursor_column;

  159.     uint8_t cursor_color;

  160.     uint8_t cursor_font;

  161.     AVBPrint buffer;

  162.     int screen_changed;

  163.     int rollup;

  164.     enum  cc_mode mode;

  165.     int64_t start_time;

  166.     /* visible screen time */

  167.     int64_t startv_time;

  168.     int64_t end_time;

  169.     char prev_cmd[2];

  170.     /* buffer to store pkt data */

  171.     uint8_t *pktbuf;

  172.     int pktbuf_size;

  173. }CCaptionSubContext;

  174. 

  175. 

  176. static av_cold int init_decoder(AVCodecContext *avctx)

  177. {

  178.     int ret;

  179.     CCaptionSubContext *ctx = avctx->priv_data;

  180. 

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

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

  183.     ctx->mode = CCMODE_ROLLUP_2;

  184.     ctx->rollup = 2;

  185.     ret = ff_ass_subtitle_header_default(avctx);

  186.     if(ret < 0) {

  187.         return ret;

  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_freep(&ctx->pktbuf);

  198.     ctx->pktbuf_size = 0;

  199.     return 0;

  200. }

  201. 

  202. /**

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

  204.  */

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

  206. {

  207.     if(col < SCREEN_COLUMNS) {

  208.         row[col] = ch;

  209.         return 0;

  210.     }

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

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

  213.         row[col] = ch;

  214.         return 0;

  215.     }

  216.     else {

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

  218.         return AVERROR_INVALIDDATA;

  219.     }

  220. }

  221. 

  222. /**

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

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

  225.  * and process the pair.

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

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

  228.  */

  229. static int validate_cc_data_pair (uint8_t *cc_data_pair)

  230. {

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

  232.     uint8_t cc_type = *cc_data_pair & 3;

  233. 

  234.     if (!cc_valid)

  235.         return AVERROR_INVALIDDATA;

  236. 

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

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

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

  240.             return AVERROR_INVALIDDATA;

  241.         }

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

  243.             cc_data_pair[1]=0x7F;

  244.         }

  245.     }

  246. 

  247.     //Skip non-data

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

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

  250.         return AVERROR_PATCHWELCOME;

  251. 

  252.     //skip 708 data

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

  254.         return AVERROR_PATCHWELCOME;

  255. 

  256.     /* remove parity bit */

  257.     cc_data_pair[1] &= 0x7F;

  258.     cc_data_pair[2] &= 0x7F;

  259. 

  260. 

  261.     return 0;

  262. 

  263. }

  264. 

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

  266. {

  267.     switch (ctx->mode) {

  268.     case CCMODE_POPON:

  269.         // use Inactive screen

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

  271.     case CCMODE_PAINTON:

  272.     case CCMODE_ROLLUP_2:

  273.     case CCMODE_ROLLUP_3:

  274.     case CCMODE_ROLLUP_4:

  275.     case CCMODE_TEXT:

  276.         // use active screen

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

  278.     }

  279.     /* It was never an option */

  280.     return NULL;

  281. }

  282. 

  283. static void roll_up(CCaptionSubContext *ctx)

  284. {

  285.     struct Screen *screen;

  286.     int i, keep_lines;

  287. 

  288.     if(ctx->mode == CCMODE_TEXT)

  289.         return;

  290. 

  291.     screen = get_writing_screen(ctx);

  292. 

  293.     /* +1 signify cursor_row starts from 0

  294.      * Can't keep lines less then row cursor pos

  295.      */

  296.     keep_lines = FFMIN(ctx->cursor_row + 1, ctx->rollup);

  297. 

  298.     for( i = 0; i < ctx->cursor_row - keep_lines; i++ )

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

  300. 

  301. 

  302.     for( i = 0; i < keep_lines && screen->row_used; i++ ) {

  303.         const int i_row = ctx->cursor_row - keep_lines + i + 1;

  304. 

  305.         memcpy( screen->characters[i_row], screen->characters[i_row+1], SCREEN_COLUMNS );

  306.         memcpy( screen->colors[i_row], screen->colors[i_row+1], SCREEN_COLUMNS);

  307.         memcpy( screen->fonts[i_row], screen->fonts[i_row+1], SCREEN_COLUMNS);

  308.         if(CHECK_FLAG(screen->row_used, i_row + 1))

  309.             SET_FLAG(screen->row_used, i_row);

  310. 

  311.     }

  312.     UNSET_FLAG(screen->row_used, ctx->cursor_row);

  313. 

  314. }

  315. 

  316. static int reap_screen(CCaptionSubContext *ctx, int64_t pts)

  317. {

  318.     int i;

  319.     int ret = 0;

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

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

  322. 

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

  324.     {

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

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

  327.             /* skip space */

  328.             while (*str == ' ')

  329.                 str++;

  330. 

  331.             av_bprintf(&ctx->buffer, "%s\\N", str);

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

  333.             if( ret == 0) {

  334.                 ret = AVERROR(ENOMEM);

  335.                 break;

  336.             }

  337.         }

  338. 

  339.     }

  340.     if(screen->row_used && ctx->buffer.len >= 2 ) {

  341.         ctx->buffer.len -= 2;

  342.         ctx->buffer.str[ctx->buffer.len] = 0;

  343.     }

  344.     ctx->startv_time = pts;

  345.     ctx->end_time = pts;

  346.     return ret;

  347. }

  348. 

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

  350. {

  351.     int i = lo - 0x20;

  352.     int ret;

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

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

  355. 

  356.     if( i >= 32)

  357.         return;

  358. 

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

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

  361. 

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

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

  364.     if(ret == 0)

  365.         ctx->cursor_column++;

  366. }

  367. 

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

  369. {

  370.     static const int8_t row_map[] = {

  371.         11, -1, 1, 2, 3, 4, 12, 13, 14, 15, 5, 6, 7, 8, 9, 10

  372.     };

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

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

  375.     char *row;

  376.     int indent,i,ret;

  377. 

  378.     if( row_map[index] <= 0 ) {

  379.         av_log(ctx, AV_LOG_DEBUG,"Invalid pac index encountered\n");

  380.         return;

  381.     }

  382. 

  383.     lo &= 0x1f;

  384. 

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

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

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

  388.     ctx->cursor_column = 0;

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

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

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

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

  393.         if(  ret == 0 )

  394.             ctx->cursor_column++;

  395.     }

  396. 

  397. }

  398. 

  399. /**

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

  401.  */

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

  403. {

  404.     int ret = 0;

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

  406. 

  407.     reap_screen(ctx, pts);

  408.     screen->row_used = 0;

  409.     ctx->screen_changed = 1;

  410.     return ret;

  411. }

  412. 

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

  414. {

  415.     int ret;

  416.     ret = handle_edm(ctx,pts);

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

  418.     ctx->cursor_column = 0;

  419.     return ret;

  420. }

  421. 

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

  423. {

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

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

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

  427. 

  428. }

  429. 

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

  431. {

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

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

  434.     int ret;

  435. 

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

  437. 

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

  439.     if( ret == 0 )

  440.         ctx->cursor_column++;

  441. 

  442.     if(lo) {

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

  444.         if ( ret == 0 )

  445.             ctx->cursor_column++;

  446.     }

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

  448. 

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

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

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

  452.     if (lo)

  453.        ff_dlog(ctx, "(%c,%c)\n",hi,lo);

  454.     else

  455.        ff_dlog(ctx, "(%c)\n",hi);

  456. }

  457. 

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

  459. {

  460.     int ret = 0;

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

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

  463.     /* ignore redundant command */

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

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

  466.         handle_pac(ctx, hi, lo);

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

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

  469.         handle_textattr(ctx, hi, lo);

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

  471.     /* resume caption loading */

  472.         ctx->mode = CCMODE_POPON;

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

  474.         handle_delete_end_of_row(ctx, hi, lo);

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

  476.         ctx->rollup = 2;

  477.         ctx->mode = CCMODE_ROLLUP_2;

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

  479.         ctx->rollup = 3;

  480.         ctx->mode = CCMODE_ROLLUP_3;

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

  482.         ctx->rollup = 4;

  483.         ctx->mode = CCMODE_ROLLUP_4;

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

  485.     /* resume direct captioning */

  486.         ctx->mode = CCMODE_PAINTON;

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

  488.     /* resume text display */

  489.         ctx->mode = CCMODE_TEXT;

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

  491.     /* erase display memory */

  492.         ret = handle_edm(ctx, pts);

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

  494.     /* carriage return */

  495.         ff_dlog(ctx, "carriage return\n");

  496.         reap_screen(ctx, pts);

  497.         roll_up(ctx);

  498.         ctx->screen_changed = 1;

  499.         ctx->cursor_column = 0;

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

  501.     /* end of caption */

  502.         ff_dlog(ctx, "handle_eoc\n");

  503.         ret = handle_eoc(ctx, pts);

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

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

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

  507.     } else {

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

  509.         ff_dlog(ctx, "Unknown command 0x%hhx 0x%hhx\n", hi, lo);

  510.     }

  511. 

  512.     /* set prev command */

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

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

  515. 

  516. #undef COR3

  517.     return ret;

  518. 

  519. }

  520. 

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

  522. {

  523.     CCaptionSubContext *ctx = avctx->priv_data;

  524.     AVSubtitle *sub = data;

  525.     uint8_t *bptr = NULL;

  526.     int len = avpkt->size;

  527.     int ret = 0;

  528.     int i;

  529. 

  530.     av_fast_padded_malloc(&ctx->pktbuf, &ctx->pktbuf_size, len);

  531.     if (!ctx->pktbuf) {

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

  533.         return AVERROR(ENOMEM);

  534.     }

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

  536.     bptr = ctx->pktbuf;

  537. 

  538. 

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

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

  541.         if (validate_cc_data_pair( bptr + i) )

  542.             continue;

  543.         /* ignoring data field 1 */

  544.         if(cc_type == 1)

  545.             continue;

  546.         else

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

  548.         if(ctx->screen_changed && *ctx->buffer.str)

  549.         {

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

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

  552.             ff_dlog(ctx, "cdp writing data (%s)\n",ctx->buffer.str);

  553.             ret = ff_ass_add_rect_bprint(sub, &ctx->buffer, start_time, end_time - start_time);

  554.             if (ret < 0)

  555.                 return ret;

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

  557.             ctx->screen_changed = 0;

  558.             av_bprint_clear(&ctx->buffer);

  559.         }

  560.     }

  561. 

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

  563.     return ret;

  564. }

  565. 

  566. static const AVOption options[] = {

  567.     {NULL}

  568. };

  569. 

  570. static const AVClass ccaption_dec_class = {

  571.     .class_name = "Closed caption Decoder",

  572.     .item_name  = av_default_item_name,

  573.     .option     = options,

  574.     .version    = LIBAVUTIL_VERSION_INT,

  575. };

  576. 

  577. AVCodec ff_ccaption_decoder = {

  578.     .name           = "cc_dec",

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

  580.     .type           = AVMEDIA_TYPE_SUBTITLE,

  581.     .id             = AV_CODEC_ID_EIA_608,

  582.     .priv_data_size = sizeof(CCaptionSubContext),

  583.     .init           = init_decoder,

  584.     .close          = close_decoder,

  585.     .decode         = decode,

  586.     .priv_class     = &ccaption_dec_class,

  587. };