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FFmpeg/libavcodec/dvdsubdec.c

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  1. /*

  2.  * DVD subtitle decoding

  3.  * Copyright (c) 2005 Fabrice Bellard

  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. #include "avcodec.h"

  22. #include "get_bits.h"

  23. #include "dsputil.h"

  24. #include "libavutil/colorspace.h"

  25. 

  26. //#define DEBUG

  27. 

  28. typedef struct DVDSubContext

  29. {

  30.   uint32_t palette[16];

  31.   int      has_palette;

  32.   uint8_t  colormap[4];

  33.   uint8_t  alpha[256];

  34. } DVDSubContext;

  35. 

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

  37. {

  38.     uint8_t *cm = ff_cropTbl + MAX_NEG_CROP;

  39.     uint8_t r, g, b;

  40.     int i, y, cb, cr;

  41.     int r_add, g_add, b_add;

  42. 

  43.     for (i = num_values; i > 0; i--) {

  44.         y = *ycbcr++;

  45.         cr = *ycbcr++;

  46.         cb = *ycbcr++;

  47.         YUV_TO_RGB1_CCIR(cb, cr);

  48.         YUV_TO_RGB2_CCIR(r, g, b, y);

  49.         *rgba++ = (*alpha++ << 24) | (r << 16) | (g << 8) | b;

  50.     }

  51. }

  52. 

  53. static int decode_run_2bit(GetBitContext *gb, int *color)

  54. {

  55.     unsigned int v, t;

  56. 

  57.     v = 0;

  58.     for (t = 1; v < t && t <= 0x40; t <<= 2)

  59.         v = (v << 4) | get_bits(gb, 4);

  60.     *color = v & 3;

  61.     if (v < 4) { /* Code for fill rest of line */

  62.         return INT_MAX;

  63.     }

  64.     return v >> 2;

  65. }

  66. 

  67. static int decode_run_8bit(GetBitContext *gb, int *color)

  68. {

  69.     int len;

  70.     int has_run = get_bits1(gb);

  71.     if (get_bits1(gb))

  72.         *color = get_bits(gb, 8);

  73.     else

  74.         *color = get_bits(gb, 2);

  75.     if (has_run) {

  76.         if (get_bits1(gb)) {

  77.             len = get_bits(gb, 7);

  78.             if (len == 0)

  79.                 len = INT_MAX;

  80.             else

  81.                 len += 9;

  82.         } else

  83.             len = get_bits(gb, 3) + 2;

  84.     } else

  85.         len = 1;

  86.     return len;

  87. }

  88. 

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

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

  91. {

  92.     GetBitContext gb;

  93.     int bit_len;

  94.     int x, y, len, color;

  95.     uint8_t *d;

  96. 

  97.     bit_len = (buf_size - start) * 8;

  98.     init_get_bits(&gb, buf + start, bit_len);

  99. 

  100.     x = 0;

  101.     y = 0;

  102.     d = bitmap;

  103.     for(;;) {

  104.         if (get_bits_count(&gb) > bit_len)

  105.             return -1;

  106.         if (is_8bit)

  107.             len = decode_run_8bit(&gb, &color);

  108.         else

  109.             len = decode_run_2bit(&gb, &color);

  110.         len = FFMIN(len, w - x);

  111.         memset(d + x, color, len);

  112.         x += len;

  113.         if (x >= w) {

  114.             y++;

  115.             if (y >= h)

  116.                 break;

  117.             d += linesize;

  118.             x = 0;

  119.             /* byte align */

  120.             align_get_bits(&gb);

  121.         }

  122.     }

  123.     return 0;

  124. }

  125. 

  126. static void guess_palette(uint32_t *rgba_palette,

  127.                           DVDSubContext* ctx,

  128.                           uint32_t subtitle_color)

  129. {

  130.     static const uint8_t level_map[4][4] = {

  131.         // this configuration (full range, lowest to highest) in tests

  132.         // seemed most common, so assume this

  133.         {0xff},

  134.         {0x00, 0xff},

  135.         {0x00, 0x80, 0xff},

  136.         {0x00, 0x55, 0xaa, 0xff},

  137.     };

  138.     uint8_t color_used[16] = { 0 };

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

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

  141. 

  142.     if(ctx->has_palette) {

  143.         for(i = 0; i < 4; i++)

  144.             rgba_palette[i] = (ctx->palette[colormap[i]] & 0x00ffffff)

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

  146.         return;

  147.     }

  148. 

  149.     for(i = 0; i < 4; i++)

  150.         rgba_palette[i] = 0;

  151. 

  152.     nb_opaque_colors = 0;

  153.     for(i = 0; i < 4; i++) {

  154.         if (alpha[i] != 0 && !color_used[colormap[i]]) {

  155.             color_used[colormap[i]] = 1;

  156.             nb_opaque_colors++;

  157.         }

  158.     }

  159. 

  160.     if (nb_opaque_colors == 0)

  161.         return;

  162. 

  163.     j = 0;

  164.     memset(color_used, 0, 16);

  165.     for(i = 0; i < 4; i++) {

  166.         if (alpha[i] != 0) {

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

  168.                 level = level_map[nb_opaque_colors][j];

  169.                 r = (((subtitle_color >> 16) & 0xff) * level) >> 8;

  170.                 g = (((subtitle_color >> 8) & 0xff) * level) >> 8;

  171.                 b = (((subtitle_color >> 0) & 0xff) * level) >> 8;

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

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

  174.                 j++;

  175.             } else {

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

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

  178.             }

  179.         }

  180.     }

  181. }

  182. 

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

  184. 

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

  186.                                 const uint8_t *buf, int buf_size)

  187. {

  188.     int cmd_pos, pos, cmd, x1, y1, x2, y2, offset1, offset2, next_cmd_pos;

  189.     int big_offsets, offset_size, is_8bit = 0;

  190.     const uint8_t *yuv_palette = 0;

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

  192.     int date;

  193.     int i;

  194.     int is_menu = 0;

  195. 

  196.     if (buf_size < 10)

  197.         return -1;

  198. 

  199.     if (AV_RB16(buf) == 0) {   /* HD subpicture with 4-byte offsets */

  200.         big_offsets = 1;

  201.         offset_size = 4;

  202.         cmd_pos = 6;

  203.     } else {

  204.         big_offsets = 0;

  205.         offset_size = 2;

  206.         cmd_pos = 2;

  207.     }

  208. 

  209.     cmd_pos = READ_OFFSET(buf + cmd_pos);

  210. 

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

  212.         date = AV_RB16(buf + cmd_pos);

  213.         next_cmd_pos = READ_OFFSET(buf + cmd_pos + 2);

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

  215.                 cmd_pos, next_cmd_pos, date);

  216.         pos = cmd_pos + 2 + offset_size;

  217.         offset1 = -1;

  218.         offset2 = -1;

  219.         x1 = y1 = x2 = y2 = 0;

  220.         while (pos < buf_size) {

  221.             cmd = buf[pos++];

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

  223.             switch(cmd) {

  224.             case 0x00:

  225.                 /* menu subpicture */

  226.                 is_menu = 1;

  227.                 break;

  228.             case 0x01:

  229.                 /* set start date */

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

  231.                 break;

  232.             case 0x02:

  233.                 /* set end date */

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

  235.                 break;

  236.             case 0x03:

  237.                 /* set colormap */

  238.                 if ((buf_size - pos) < 2)

  239.                     goto fail;

  240.                 colormap[3] = buf[pos] >> 4;

  241.                 colormap[2] = buf[pos] & 0x0f;

  242.                 colormap[1] = buf[pos + 1] >> 4;

  243.                 colormap[0] = buf[pos + 1] & 0x0f;

  244.                 pos += 2;

  245.                 break;

  246.             case 0x04:

  247.                 /* set alpha */

  248.                 if ((buf_size - pos) < 2)

  249.                     goto fail;

  250.                 alpha[3] = buf[pos] >> 4;

  251.                 alpha[2] = buf[pos] & 0x0f;

  252.                 alpha[1] = buf[pos + 1] >> 4;

  253.                 alpha[0] = buf[pos + 1] & 0x0f;

  254.                 pos += 2;

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

  256.                 break;

  257.             case 0x05:

  258.             case 0x85:

  259.                 if ((buf_size - pos) < 6)

  260.                     goto fail;

  261.                 x1 = (buf[pos] << 4) | (buf[pos + 1] >> 4);

  262.                 x2 = ((buf[pos + 1] & 0x0f) << 8) | buf[pos + 2];

  263.                 y1 = (buf[pos + 3] << 4) | (buf[pos + 4] >> 4);

  264.                 y2 = ((buf[pos + 4] & 0x0f) << 8) | buf[pos + 5];

  265.                 if (cmd & 0x80)

  266.                     is_8bit = 1;

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

  268.                 pos += 6;

  269.                 break;

  270.             case 0x06:

  271.                 if ((buf_size - pos) < 4)

  272.                     goto fail;

  273.                 offset1 = AV_RB16(buf + pos);

  274.                 offset2 = AV_RB16(buf + pos + 2);

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

  276.                 pos += 4;

  277.                 break;

  278.             case 0x86:

  279.                 if ((buf_size - pos) < 8)

  280.                     goto fail;

  281.                 offset1 = AV_RB32(buf + pos);

  282.                 offset2 = AV_RB32(buf + pos + 4);

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

  284.                 pos += 8;

  285.                 break;

  286. 

  287.             case 0x83:

  288.                 /* HD set palette */

  289.                 if ((buf_size - pos) < 768)

  290.                     goto fail;

  291.                 yuv_palette = buf + pos;

  292.                 pos += 768;

  293.                 break;

  294.             case 0x84:

  295.                 /* HD set contrast (alpha) */

  296.                 if ((buf_size - pos) < 256)

  297.                     goto fail;

  298.                 for (i = 0; i < 256; i++)

  299.                     alpha[i] = 0xFF - buf[pos+i];

  300.                 pos += 256;

  301.                 break;

  302. 

  303.             case 0xff:

  304.                 goto the_end;

  305.             default:

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

  307.                 goto the_end;

  308.             }

  309.         }

  310.     the_end:

  311.         if (offset1 >= 0) {

  312.             int w, h;

  313.             uint8_t *bitmap;

  314. 

  315.             /* decode the bitmap */

  316.             w = x2 - x1 + 1;

  317.             if (w < 0)

  318.                 w = 0;

  319.             h = y2 - y1;

  320.             if (h < 0)

  321.                 h = 0;

  322.             if (w > 0 && h > 0) {

  323.                 if (sub_header->rects != NULL) {

  324.                     for (i = 0; i < sub_header->num_rects; i++) {

  325.                         av_freep(&sub_header->rects[i]->pict.data[0]);

  326.                         av_freep(&sub_header->rects[i]->pict.data[1]);

  327.                         av_freep(&sub_header->rects[i]);

  328.                     }

  329.                     av_freep(&sub_header->rects);

  330.                     sub_header->num_rects = 0;

  331.                 }

  332. 

  333.                 bitmap = av_malloc(w * h);

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

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

  336.                 sub_header->num_rects = 1;

  337.                 sub_header->rects[0]->pict.data[0] = bitmap;

  338.                 decode_rle(bitmap, w * 2, w, (h + 1) / 2,

  339.                            buf, offset1, buf_size, is_8bit);

  340.                 decode_rle(bitmap + w, w * 2, w, h / 2,

  341.                            buf, offset2, buf_size, is_8bit);

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

  343.                 if (is_8bit) {

  344.                     if (yuv_palette == 0)

  345.                         goto fail;

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

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

  348.                 } else {

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

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

  351.                                   0xffff00);

  352.                 }

  353.                 sub_header->rects[0]->x = x1;

  354.                 sub_header->rects[0]->y = y1;

  355.                 sub_header->rects[0]->w = w;

  356.                 sub_header->rects[0]->h = h;

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

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

  359.             }

  360.         }

  361.         if (next_cmd_pos < cmd_pos) {

  362.             av_log(NULL, AV_LOG_ERROR, "Invalid command offset\n");

  363.             break;

  364.         }

  365.         if (next_cmd_pos == cmd_pos)

  366.             break;

  367.         cmd_pos = next_cmd_pos;

  368.     }

  369.     if (sub_header->num_rects > 0)

  370.         return is_menu;

  371.  fail:

  372.     if (sub_header->rects != NULL) {

  373.         for (i = 0; i < sub_header->num_rects; i++) {

  374.             av_freep(&sub_header->rects[i]->pict.data[0]);

  375.             av_freep(&sub_header->rects[i]->pict.data[1]);

  376.             av_freep(&sub_header->rects[i]);

  377.         }

  378.         av_freep(&sub_header->rects);

  379.         sub_header->num_rects = 0;

  380.     }

  381.     return -1;

  382. }

  383. 

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

  385.                      const uint8_t *transp_color)

  386. {

  387.     int i;

  388.     for(i = 0; i < n; i++) {

  389.         if (!transp_color[*buf])

  390.             return 0;

  391.         buf += pitch;

  392.     }

  393.     return 1;

  394. }

  395. 

  396. /* return 0 if empty rectangle, 1 if non empty */

  397. static int find_smallest_bounding_rectangle(AVSubtitle *s)

  398. {

  399.     uint8_t transp_color[256] = { 0 };

  400.     int y1, y2, x1, x2, y, w, h, i;

  401.     uint8_t *bitmap;

  402. 

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

  404.         return 0;

  405. 

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

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

  408.             transp_color[i] = 1;

  409.     }

  410.     y1 = 0;

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

  412.                                   1, s->rects[0]->w, transp_color))

  413.         y1++;

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

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

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

  417.         return 0;

  418.     }

  419. 

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

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

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

  423.         y2--;

  424.     x1 = 0;

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

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

  427.         x1++;

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

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

  430.                                   transp_color))

  431.         x2--;

  432.     w = x2 - x1 + 1;

  433.     h = y2 - y1 + 1;

  434.     bitmap = av_malloc(w * h);

  435.     if (!bitmap)

  436.         return 1;

  437.     for(y = 0; y < h; y++) {

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

  439.     }

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

  441.     s->rects[0]->pict.data[0] = bitmap;

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

  443.     s->rects[0]->w = w;

  444.     s->rects[0]->h = h;

  445.     s->rects[0]->x += x1;

  446.     s->rects[0]->y += y1;

  447.     return 1;

  448. }

  449. 

  450. #ifdef DEBUG

  451. #undef fprintf

  452. #undef perror

  453. #undef exit

  454. static void ppm_save(const char *filename, uint8_t *bitmap, int w, int h,

  455.                      uint32_t *rgba_palette)

  456. {

  457.     int x, y, v;

  458.     FILE *f;

  459. 

  460.     f = fopen(filename, "w");

  461.     if (!f) {

  462.         perror(filename);

  463.         exit(1);

  464.     }

  465.     fprintf(f, "P6\n"

  466.             "%d %d\n"

  467.             "%d\n",

  468.             w, h, 255);

  469.     for(y = 0; y < h; y++) {

  470.         for(x = 0; x < w; x++) {

  471.             v = rgba_palette[bitmap[y * w + x]];

  472.             putc((v >> 16) & 0xff, f);

  473.             putc((v >> 8) & 0xff, f);

  474.             putc((v >> 0) & 0xff, f);

  475.         }

  476.     }

  477.     fclose(f);

  478. }

  479. #endif

  480. 

  481. static int dvdsub_decode(AVCodecContext *avctx,

  482.                          void *data, int *data_size,

  483.                          AVPacket *avpkt)

  484. {

  485.     DVDSubContext *ctx = (DVDSubContext*) avctx->priv_data;

  486.     const uint8_t *buf = avpkt->data;

  487.     int buf_size = avpkt->size;

  488.     AVSubtitle *sub = data;

  489.     int is_menu;

  490. 

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

  492. 

  493.     if (is_menu < 0) {

  494.     no_subtitle:

  495.         *data_size = 0;

  496. 

  497.         return buf_size;

  498.     }

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

  500.         goto no_subtitle;

  501. 

  502. #if defined(DEBUG)

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

  504.             sub->start_display_time,

  505.             sub->end_display_time);

  506.     ppm_save("/tmp/a.ppm", sub->rects[0]->pict.data[0],

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

  508. #endif

  509. 

  510.     *data_size = 1;

  511.     return buf_size;

  512. }

  513. 

  514. static int dvdsub_init(AVCodecContext *avctx)

  515. {

  516.     DVDSubContext *ctx = (DVDSubContext*) avctx->priv_data;

  517.     char *dataorig, *data;

  518. 

  519.     if (!avctx->extradata || !avctx->extradata_size)

  520.         return 1;

  521. 

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

  523.     if (!data)

  524.         return AVERROR(ENOMEM);

  525.     memcpy(data, avctx->extradata, avctx->extradata_size);

  526.     data[avctx->extradata_size] = '\0';

  527. 

  528.     for(;;) {

  529.         int pos = strcspn(data, "\n\r");

  530.         if (pos==0 && *data==0)

  531.             break;

  532. 

  533.         if (strncmp("palette:", data, 8) == 0) {

  534.             int i;

  535.             char *p = data+8;

  536.             ctx->has_palette = 1;

  537.             for(i=0;i<16;i++) {

  538.                 ctx->palette[i] = strtoul(p, &p, 16);

  539.                 while(*p == ',' || isspace(*p))

  540.                     p++;

  541.             }

  542.         }

  543. 

  544.         data += pos;

  545.         data += strspn(data, "\n\r");

  546.     }

  547. 

  548.     if (ctx->has_palette) {

  549.         int i;

  550.         av_log(avctx, AV_LOG_DEBUG, "palette:");

  551.         for(i=0;i<16;i++)

  552.             av_log(avctx, AV_LOG_DEBUG, " 0x%06x", ctx->palette[i]);

  553.         av_log(avctx, AV_LOG_DEBUG, "\n");

  554.     }

  555. 

  556.     av_free(dataorig);

  557.     return 1;

  558. }

  559. 

  560. AVCodec ff_dvdsub_decoder = {

  561.     .name           = "dvdsub",

  562.     .type           = AVMEDIA_TYPE_SUBTITLE,

  563.     .id             = CODEC_ID_DVD_SUBTITLE,

  564.     .priv_data_size = sizeof(DVDSubContext),

  565.     .init           = dvdsub_init,

  566.     .decode         = dvdsub_decode,

  567.     .long_name      = NULL_IF_CONFIG_SMALL("DVD subtitles"),

  568. };