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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 "internal.h"

  25. 

  26. #include "libavutil/attributes.h"

  27. #include "libavutil/colorspace.h"

  28. #include "libavutil/imgutils.h"

  29. #include "libavutil/avstring.h"

  30. 

  31. typedef struct DVDSubContext {

  32.     uint32_t palette[16];

  33.     int      has_palette;

  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.     const uint8_t *cm = ff_crop_tab + 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(DVDSubContext* ctx,

  127.                           uint32_t *rgba_palette,

  128.                           uint8_t *colormap,

  129.                           uint8_t *alpha,

  130.                           uint32_t subtitle_color)

  131. {

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

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

  134. 

  135.     if (ctx->has_palette) {

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

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

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

  139.         return;

  140.     }

  141. 

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

  143.         rgba_palette[i] = 0;

  144. 

  145.     nb_opaque_colors = 0;

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

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

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

  149.             nb_opaque_colors++;

  150.         }

  151.     }

  152. 

  153.     if (nb_opaque_colors == 0)

  154.         return;

  155. 

  156.     j = nb_opaque_colors;

  157.     memset(color_used, 0, 16);

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

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

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

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

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

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

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

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

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

  167.                 j--;

  168.             } else {

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

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

  171.             }

  172.         }

  173.     }

  174. }

  175. 

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

  177. 

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

  179.                                 const uint8_t *buf, int buf_size)

  180. {

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

  182.     int big_offsets, offset_size, is_8bit = 0;

  183.     const uint8_t *yuv_palette = 0;

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

  185.     int date;

  186.     int i;

  187.     int is_menu = 0;

  188. 

  189.     if (buf_size < 10)

  190.         return -1;

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

  192. 

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

  194.         big_offsets = 1;

  195.         offset_size = 4;

  196.         cmd_pos = 6;

  197.     } else {

  198.         big_offsets = 0;

  199.         offset_size = 2;

  200.         cmd_pos = 2;

  201.     }

  202. 

  203.     cmd_pos = READ_OFFSET(buf + cmd_pos);

  204. 

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

  206.         date = AV_RB16(buf + cmd_pos);

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

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

  209.                 cmd_pos, next_cmd_pos, date);

  210.         pos = cmd_pos + 2 + offset_size;

  211.         offset1 = -1;

  212.         offset2 = -1;

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

  214.         while (pos < buf_size) {

  215.             cmd = buf[pos++];

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

  217.             switch(cmd) {

  218.             case 0x00:

  219.                 /* menu subpicture */

  220.                 is_menu = 1;

  221.                 break;

  222.             case 0x01:

  223.                 /* set start date */

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

  225.                 break;

  226.             case 0x02:

  227.                 /* set end date */

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

  229.                 break;

  230.             case 0x03:

  231.                 /* set colormap */

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

  233.                     goto fail;

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

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

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

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

  238.                 pos += 2;

  239.                 break;

  240.             case 0x04:

  241.                 /* set alpha */

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

  243.                     goto fail;

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

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

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

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

  248.                 pos += 2;

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

  250.                 break;

  251.             case 0x05:

  252.             case 0x85:

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

  254.                     goto fail;

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

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

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

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

  259.                 if (cmd & 0x80)

  260.                     is_8bit = 1;

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

  262.                 pos += 6;

  263.                 break;

  264.             case 0x06:

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

  266.                     goto fail;

  267.                 offset1 = AV_RB16(buf + pos);

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

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

  270.                 pos += 4;

  271.                 break;

  272.             case 0x86:

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

  274.                     goto fail;

  275.                 offset1 = AV_RB32(buf + pos);

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

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

  278.                 pos += 8;

  279.                 break;

  280. 

  281.             case 0x83:

  282.                 /* HD set palette */

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

  284.                     goto fail;

  285.                 yuv_palette = buf + pos;

  286.                 pos += 768;

  287.                 break;

  288.             case 0x84:

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

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

  291.                     goto fail;

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

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

  294.                 pos += 256;

  295.                 break;

  296. 

  297.             case 0xff:

  298.                 goto the_end;

  299.             default:

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

  301.                 goto the_end;

  302.             }

  303.         }

  304.     the_end:

  305.         if (offset1 >= 0) {

  306.             int w, h;

  307.             uint8_t *bitmap;

  308. 

  309.             /* decode the bitmap */

  310.             w = x2 - x1 + 1;

  311.             if (w < 0)

  312.                 w = 0;

  313.             h = y2 - y1;

  314.             if (h < 0)

  315.                 h = 0;

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

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

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

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

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

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

  322.                     }

  323.                     av_freep(&sub_header->rects);

  324.                     sub_header->num_rects = 0;

  325.                 }

  326. 

  327.                 bitmap = av_malloc(w * h);

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

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

  330.                 sub_header->num_rects = 1;

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

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

  333.                            buf, offset1, buf_size, is_8bit);

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

  335.                            buf, offset2, buf_size, is_8bit);

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

  337.                 if (is_8bit) {

  338.                     if (yuv_palette == 0)

  339.                         goto fail;

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

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

  342.                 } else {

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

  344.                     guess_palette(ctx,

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

  346.                                   colormap, alpha, 0xffff00);

  347.                 }

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

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

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

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

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

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

  354.             }

  355.         }

  356.         if (next_cmd_pos == cmd_pos)

  357.             break;

  358.         cmd_pos = next_cmd_pos;

  359.     }

  360.     if (sub_header->num_rects > 0)

  361.         return is_menu;

  362.  fail:

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

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

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

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

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

  368.         }

  369.         av_freep(&sub_header->rects);

  370.         sub_header->num_rects = 0;

  371.     }

  372.     return -1;

  373. }

  374. 

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

  376.                      const uint8_t *transp_color)

  377. {

  378.     int i;

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

  380.         if (!transp_color[*buf])

  381.             return 0;

  382.         buf += pitch;

  383.     }

  384.     return 1;

  385. }

  386. 

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

  388. static int find_smallest_bounding_rectangle(AVSubtitle *s)

  389. {

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

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

  392.     uint8_t *bitmap;

  393. 

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

  395.         return 0;

  396. 

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

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

  399.             transp_color[i] = 1;

  400.     }

  401.     y1 = 0;

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

  403.                                   1, s->rects[0]->w, transp_color))

  404.         y1++;

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

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

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

  408.         return 0;

  409.     }

  410. 

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

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

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

  414.         y2--;

  415.     x1 = 0;

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

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

  418.         x1++;

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

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

  421.                                   transp_color))

  422.         x2--;

  423.     w = x2 - x1 + 1;

  424.     h = y2 - y1 + 1;

  425.     bitmap = av_malloc(w * h);

  426.     if (!bitmap)

  427.         return 1;

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

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

  430.     }

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

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

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

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

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

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

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

  438.     return 1;

  439. }

  440. 

  441. #ifdef DEBUG

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

  443.                      uint32_t *rgba_palette)

  444. {

  445.     int x, y, v;

  446.     FILE *f;

  447. 

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

  449.     if (!f) {

  450.         perror(filename);

  451.         exit(1);

  452.     }

  453.     fprintf(f, "P6\n"

  454.             "%d %d\n"

  455.             "%d\n",

  456.             w, h, 255);

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

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

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

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

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

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

  463.         }

  464.     }

  465.     fclose(f);

  466. }

  467. #endif

  468. 

  469. static int dvdsub_decode(AVCodecContext *avctx,

  470.                          void *data, int *data_size,

  471.                          AVPacket *avpkt)

  472. {

  473.     DVDSubContext *ctx = avctx->priv_data;

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

  475.     int buf_size = avpkt->size;

  476.     AVSubtitle *sub = data;

  477.     int is_menu;

  478. 

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

  480. 

  481.     if (is_menu < 0) {

  482.     no_subtitle:

  483.         *data_size = 0;

  484. 

  485.         return buf_size;

  486.     }

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

  488.         goto no_subtitle;

  489. 

  490. #if defined(DEBUG)

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

  492.             sub->start_display_time,

  493.             sub->end_display_time);

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

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

  496. #endif

  497. 

  498.     *data_size = 1;

  499.     return buf_size;

  500. }

  501. 

  502. static av_cold int dvdsub_init(AVCodecContext *avctx)

  503. {

  504.     DVDSubContext *ctx = avctx->priv_data;

  505.     char *data, *cur;

  506. 

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

  508.         return 0;

  509. 

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

  511.     if (!data)

  512.         return AVERROR(ENOMEM);

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

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

  515.     cur = data;

  516. 

  517.     while (*cur) {

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

  519.             int i;

  520.             char *p = cur + 8;

  521.             ctx->has_palette = 1;

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

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

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

  525.                     p++;

  526.             }

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

  528.             int w, h;

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

  530.                int ret = ff_set_dimensions(avctx, w, h);

  531.                if (ret < 0)

  532.                    return ret;

  533.             }

  534.         }

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

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

  537.     }

  538.     av_free(data);

  539.     return 0;

  540. }

  541. 

  542. AVCodec ff_dvdsub_decoder = {

  543.     .name           = "dvdsub",

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

  545.     .type           = AVMEDIA_TYPE_SUBTITLE,

  546.     .id             = AV_CODEC_ID_DVD_SUBTITLE,

  547.     .priv_data_size = sizeof(DVDSubContext),

  548.     .init           = dvdsub_init,

  549.     .decode         = dvdsub_decode,

  550. };