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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 Libav.

  6.  *

  7.  * Libav 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.  * Libav 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 Libav; 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/attributes.h"

  25. #include "libavutil/colorspace.h"

  26. #include "libavutil/imgutils.h"

  27. #include "libavutil/avstring.h"

  28. 

  29. typedef struct DVDSubContext {

  30.     uint32_t palette[16];

  31.     int      has_palette;

  32. } DVDSubContext;

  33. 

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

  35. {

  36.     const uint8_t *cm = ff_cropTbl + MAX_NEG_CROP;

  37.     uint8_t r, g, b;

  38.     int i, y, cb, cr;

  39.     int r_add, g_add, b_add;

  40. 

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

  42.         y = *ycbcr++;

  43.         cr = *ycbcr++;

  44.         cb = *ycbcr++;

  45.         YUV_TO_RGB1_CCIR(cb, cr);

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

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

  48.     }

  49. }

  50. 

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

  52. {

  53.     unsigned int v, t;

  54. 

  55.     v = 0;

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

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

  58.     *color = v & 3;

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

  60.         return INT_MAX;

  61.     }

  62.     return v >> 2;

  63. }

  64. 

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

  66. {

  67.     int len;

  68.     int has_run = get_bits1(gb);

  69.     if (get_bits1(gb))

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

  71.     else

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

  73.     if (has_run) {

  74.         if (get_bits1(gb)) {

  75.             len = get_bits(gb, 7);

  76.             if (len == 0)

  77.                 len = INT_MAX;

  78.             else

  79.                 len += 9;

  80.         } else

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

  82.     } else

  83.         len = 1;

  84.     return len;

  85. }

  86. 

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

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

  89. {

  90.     GetBitContext gb;

  91.     int bit_len;

  92.     int x, y, len, color;

  93.     uint8_t *d;

  94. 

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

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

  97. 

  98.     x = 0;

  99.     y = 0;

  100.     d = bitmap;

  101.     for(;;) {

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

  103.             return -1;

  104.         if (is_8bit)

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

  106.         else

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

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

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

  110.         x += len;

  111.         if (x >= w) {

  112.             y++;

  113.             if (y >= h)

  114.                 break;

  115.             d += linesize;

  116.             x = 0;

  117.             /* byte align */

  118.             align_get_bits(&gb);

  119.         }

  120.     }

  121.     return 0;

  122. }

  123. 

  124. static void guess_palette(DVDSubContext* ctx,

  125.                           uint32_t *rgba_palette,

  126.                           uint8_t *colormap,

  127.                           uint8_t *alpha,

  128.                           uint32_t subtitle_color)

  129. {

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

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

  132. 

  133.     if (ctx->has_palette) {

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

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

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

  137.         return;

  138.     }

  139. 

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

  141.         rgba_palette[i] = 0;

  142. 

  143.     nb_opaque_colors = 0;

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

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

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

  147.             nb_opaque_colors++;

  148.         }

  149.     }

  150. 

  151.     if (nb_opaque_colors == 0)

  152.         return;

  153. 

  154.     j = nb_opaque_colors;

  155.     memset(color_used, 0, 16);

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

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

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

  159.                 level = (0xff * j) / nb_opaque_colors;

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

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

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

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

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

  165.                 j--;

  166.             } else {

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

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

  169.             }

  170.         }

  171.     }

  172. }

  173. 

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

  175. 

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

  177.                                 const uint8_t *buf, int buf_size)

  178. {

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

  180.     int big_offsets, offset_size, is_8bit = 0;

  181.     const uint8_t *yuv_palette = 0;

  182.     uint8_t colormap[4] = { 0 }, alpha[256] = { 0 };

  183.     int date;

  184.     int i;

  185.     int is_menu = 0;

  186. 

  187.     if (buf_size < 10)

  188.         return -1;

  189.     memset(sub_header, 0, sizeof(*sub_header));

  190. 

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

  192.         big_offsets = 1;

  193.         offset_size = 4;

  194.         cmd_pos = 6;

  195.     } else {

  196.         big_offsets = 0;

  197.         offset_size = 2;

  198.         cmd_pos = 2;

  199.     }

  200. 

  201.     cmd_pos = READ_OFFSET(buf + cmd_pos);

  202. 

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

  204.         date = AV_RB16(buf + cmd_pos);

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

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

  207.                 cmd_pos, next_cmd_pos, date);

  208.         pos = cmd_pos + 2 + offset_size;

  209.         offset1 = -1;

  210.         offset2 = -1;

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

  212.         while (pos < buf_size) {

  213.             cmd = buf[pos++];

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

  215.             switch(cmd) {

  216.             case 0x00:

  217.                 /* menu subpicture */

  218.                 is_menu = 1;

  219.                 break;

  220.             case 0x01:

  221.                 /* set start date */

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

  223.                 break;

  224.             case 0x02:

  225.                 /* set end date */

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

  227.                 break;

  228.             case 0x03:

  229.                 /* set colormap */

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

  231.                     goto fail;

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

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

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

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

  236.                 pos += 2;

  237.                 break;

  238.             case 0x04:

  239.                 /* set alpha */

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

  241.                     goto fail;

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

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

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

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

  246.                 pos += 2;

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

  248.                 break;

  249.             case 0x05:

  250.             case 0x85:

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

  252.                     goto fail;

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

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

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

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

  257.                 if (cmd & 0x80)

  258.                     is_8bit = 1;

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

  260.                 pos += 6;

  261.                 break;

  262.             case 0x06:

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

  264.                     goto fail;

  265.                 offset1 = AV_RB16(buf + pos);

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

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

  268.                 pos += 4;

  269.                 break;

  270.             case 0x86:

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

  272.                     goto fail;

  273.                 offset1 = AV_RB32(buf + pos);

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

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

  276.                 pos += 8;

  277.                 break;

  278. 

  279.             case 0x83:

  280.                 /* HD set palette */

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

  282.                     goto fail;

  283.                 yuv_palette = buf + pos;

  284.                 pos += 768;

  285.                 break;

  286.             case 0x84:

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

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

  289.                     goto fail;

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

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

  292.                 pos += 256;

  293.                 break;

  294. 

  295.             case 0xff:

  296.                 goto the_end;

  297.             default:

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

  299.                 goto the_end;

  300.             }

  301.         }

  302.     the_end:

  303.         if (offset1 >= 0) {

  304.             int w, h;

  305.             uint8_t *bitmap;

  306. 

  307.             /* decode the bitmap */

  308.             w = x2 - x1 + 1;

  309.             if (w < 0)

  310.                 w = 0;

  311.             h = y2 - y1;

  312.             if (h < 0)

  313.                 h = 0;

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

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

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

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

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

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

  320.                     }

  321.                     av_freep(&sub_header->rects);

  322.                     sub_header->num_rects = 0;

  323.                 }

  324. 

  325.                 bitmap = av_malloc(w * h);

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

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

  328.                 sub_header->num_rects = 1;

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

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

  331.                            buf, offset1, buf_size, is_8bit);

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

  333.                            buf, offset2, buf_size, is_8bit);

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

  335.                 if (is_8bit) {

  336.                     if (yuv_palette == 0)

  337.                         goto fail;

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

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

  340.                 } else {

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

  342.                     guess_palette(ctx,

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

  344.                                   colormap, alpha, 0xffff00);

  345.                 }

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

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

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

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

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

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

  352.             }

  353.         }

  354.         if (next_cmd_pos == cmd_pos)

  355.             break;

  356.         cmd_pos = next_cmd_pos;

  357.     }

  358.     if (sub_header->num_rects > 0)

  359.         return is_menu;

  360.  fail:

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

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

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

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

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

  366.         }

  367.         av_freep(&sub_header->rects);

  368.         sub_header->num_rects = 0;

  369.     }

  370.     return -1;

  371. }

  372. 

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

  374.                      const uint8_t *transp_color)

  375. {

  376.     int i;

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

  378.         if (!transp_color[*buf])

  379.             return 0;

  380.         buf += pitch;

  381.     }

  382.     return 1;

  383. }

  384. 

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

  386. static int find_smallest_bounding_rectangle(AVSubtitle *s)

  387. {

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

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

  390.     uint8_t *bitmap;

  391. 

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

  393.         return 0;

  394. 

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

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

  397.             transp_color[i] = 1;

  398.     }

  399.     y1 = 0;

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

  401.                                   1, s->rects[0]->w, transp_color))

  402.         y1++;

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

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

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

  406.         return 0;

  407.     }

  408. 

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

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

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

  412.         y2--;

  413.     x1 = 0;

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

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

  416.         x1++;

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

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

  419.                                   transp_color))

  420.         x2--;

  421.     w = x2 - x1 + 1;

  422.     h = y2 - y1 + 1;

  423.     bitmap = av_malloc(w * h);

  424.     if (!bitmap)

  425.         return 1;

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

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

  428.     }

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

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

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

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

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

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

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

  436.     return 1;

  437. }

  438. 

  439. #ifdef DEBUG

  440. #undef fprintf

  441. #undef perror

  442. #undef exit

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

  444.                      uint32_t *rgba_palette)

  445. {

  446.     int x, y, v;

  447.     FILE *f;

  448. 

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

  450.     if (!f) {

  451.         perror(filename);

  452.         exit(1);

  453.     }

  454.     fprintf(f, "P6\n"

  455.             "%d %d\n"

  456.             "%d\n",

  457.             w, h, 255);

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

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

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

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

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

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

  464.         }

  465.     }

  466.     fclose(f);

  467. }

  468. #endif

  469. 

  470. static int dvdsub_decode(AVCodecContext *avctx,

  471.                          void *data, int *data_size,

  472.                          AVPacket *avpkt)

  473. {

  474.     DVDSubContext *ctx = avctx->priv_data;

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

  476.     int buf_size = avpkt->size;

  477.     AVSubtitle *sub = data;

  478.     int is_menu;

  479. 

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

  481. 

  482.     if (is_menu < 0) {

  483.     no_subtitle:

  484.         *data_size = 0;

  485. 

  486.         return buf_size;

  487.     }

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

  489.         goto no_subtitle;

  490. 

  491. #if defined(DEBUG)

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

  493.             sub->start_display_time,

  494.             sub->end_display_time);

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

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

  497. #endif

  498. 

  499.     *data_size = 1;

  500.     return buf_size;

  501. }

  502. 

  503. static av_cold int dvdsub_init(AVCodecContext *avctx)

  504. {

  505.     DVDSubContext *ctx = avctx->priv_data;

  506.     char *data, *cur;

  507. 

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

  509.         return 0;

  510. 

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

  512.     if (!data)

  513.         return AVERROR(ENOMEM);

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

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

  516.     cur = data;

  517. 

  518.     while (*cur) {

  519.         if (strncmp("palette:", cur, 8) == 0) {

  520.             int i;

  521.             char *p = cur + 8;

  522.             ctx->has_palette = 1;

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

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

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

  526.                     p++;

  527.             }

  528.         } else if (!strncmp("size:", cur, 5)) {

  529.             int w, h;

  530.             if (sscanf(cur + 5, "%dx%d", &w, &h) == 2 &&

  531.                 av_image_check_size(w, h, 0, avctx) >= 0)

  532.                 avcodec_set_dimensions(avctx, w, h);

  533.         }

  534.         cur += strcspn(cur, "\n\r");

  535.         cur += strspn(cur, "\n\r");

  536.     }

  537.     av_free(data);

  538.     return 0;

  539. }

  540. 

  541. AVCodec ff_dvdsub_decoder = {

  542.     .name           = "dvdsub",

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

  544.     .type           = AVMEDIA_TYPE_SUBTITLE,

  545.     .id             = AV_CODEC_ID_DVD_SUBTITLE,

  546.     .priv_data_size = sizeof(DVDSubContext),

  547.     .init           = dvdsub_init,

  548.     .decode         = dvdsub_decode,

  549. };