2 * DVD subtitle decoding for ffmpeg
3 * Copyright (c) 2005 Fabrice Bellard.
5 * This file is part of FFmpeg.
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.
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.
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
22 #include "bitstream.h"
23 #include "colorspace.h"
28 static void yuv_a_to_rgba(const uint8_t *ycbcr, const uint8_t *alpha, uint32_t *rgba, int num_values)
30 uint8_t *cm = ff_cropTbl + MAX_NEG_CROP;
33 int r_add, g_add, b_add;
35 for (i = num_values; i > 0; i--) {
39 YUV_TO_RGB1_CCIR(cb, cr);
40 YUV_TO_RGB2_CCIR(r, g, b, y);
41 *rgba++ = (*alpha++ << 24) | (r << 16) | (g << 8) | b;
45 static int decode_run_2bit(GetBitContext *gb, int *color)
50 for (t = 1; v < t && t <= 0x40; t <<= 2)
51 v = (v << 4) | get_bits(gb, 4);
53 if (v < 4) { /* Code for fill rest of line */
59 static int decode_run_8bit(GetBitContext *gb, int *color)
62 int has_run = get_bits1(gb);
64 *color = get_bits(gb, 8);
66 *color = get_bits(gb, 2);
69 len = get_bits(gb, 7);
75 len = get_bits(gb, 3) + 2;
81 static int decode_rle(uint8_t *bitmap, int linesize, int w, int h,
82 const uint8_t *buf, int start, int buf_size, int is_8bit)
89 bit_len = (buf_size - start) * 8;
90 init_get_bits(&gb, buf + start, bit_len);
96 if (get_bits_count(&gb) > bit_len)
99 len = decode_run_8bit(&gb, &color);
101 len = decode_run_2bit(&gb, &color);
102 len = FFMIN(len, w - x);
103 memset(d + x, color, len);
118 static void guess_palette(uint32_t *rgba_palette,
121 uint32_t subtitle_color)
123 uint8_t color_used[16];
124 int nb_opaque_colors, i, level, j, r, g, b;
126 for(i = 0; i < 4; i++)
129 memset(color_used, 0, 16);
130 nb_opaque_colors = 0;
131 for(i = 0; i < 4; i++) {
132 if (alpha[i] != 0 && !color_used[colormap[i]]) {
133 color_used[colormap[i]] = 1;
138 if (nb_opaque_colors == 0)
141 j = nb_opaque_colors;
142 memset(color_used, 0, 16);
143 for(i = 0; i < 4; i++) {
145 if (!color_used[colormap[i]]) {
146 level = (0xff * j) / nb_opaque_colors;
147 r = (((subtitle_color >> 16) & 0xff) * level) >> 8;
148 g = (((subtitle_color >> 8) & 0xff) * level) >> 8;
149 b = (((subtitle_color >> 0) & 0xff) * level) >> 8;
150 rgba_palette[i] = b | (g << 8) | (r << 16) | ((alpha[i] * 17) << 24);
151 color_used[colormap[i]] = (i + 1);
154 rgba_palette[i] = (rgba_palette[color_used[colormap[i]] - 1] & 0x00ffffff) |
155 ((alpha[i] * 17) << 24);
161 #define READ_OFFSET(a) (big_offsets ? AV_RB32(a) : AV_RB16(a))
163 static int decode_dvd_subtitles(AVSubtitle *sub_header,
164 const uint8_t *buf, int buf_size)
166 int cmd_pos, pos, cmd, x1, y1, x2, y2, offset1, offset2, next_cmd_pos;
167 int big_offsets, offset_size, is_8bit = 0;
168 const uint8_t *yuv_palette = 0;
169 uint8_t colormap[4], alpha[256];
176 sub_header->rects = NULL;
177 sub_header->num_rects = 0;
178 sub_header->start_display_time = 0;
179 sub_header->end_display_time = 0;
181 if (AV_RB16(buf) == 0) { /* HD subpicture with 4-byte offsets */
191 cmd_pos = READ_OFFSET(buf + cmd_pos);
193 while ((cmd_pos + 2 + offset_size) < buf_size) {
194 date = AV_RB16(buf + cmd_pos);
195 next_cmd_pos = READ_OFFSET(buf + cmd_pos + 2);
197 av_log(NULL, AV_LOG_INFO, "cmd_pos=0x%04x next=0x%04x date=%d\n",
198 cmd_pos, next_cmd_pos, date);
200 pos = cmd_pos + 2 + offset_size;
203 x1 = y1 = x2 = y2 = 0;
204 while (pos < buf_size) {
207 av_log(NULL, AV_LOG_INFO, "cmd=%02x\n", cmd);
211 /* menu subpicture */
216 sub_header->start_display_time = (date << 10) / 90;
220 sub_header->end_display_time = (date << 10) / 90;
224 if ((buf_size - pos) < 2)
226 colormap[3] = buf[pos] >> 4;
227 colormap[2] = buf[pos] & 0x0f;
228 colormap[1] = buf[pos + 1] >> 4;
229 colormap[0] = buf[pos + 1] & 0x0f;
234 if ((buf_size - pos) < 2)
236 alpha[3] = buf[pos] >> 4;
237 alpha[2] = buf[pos] & 0x0f;
238 alpha[1] = buf[pos + 1] >> 4;
239 alpha[0] = buf[pos + 1] & 0x0f;
242 av_log(NULL, AV_LOG_INFO, "alpha=%x%x%x%x\n", alpha[0],alpha[1],alpha[2],alpha[3]);
247 if ((buf_size - pos) < 6)
249 x1 = (buf[pos] << 4) | (buf[pos + 1] >> 4);
250 x2 = ((buf[pos + 1] & 0x0f) << 8) | buf[pos + 2];
251 y1 = (buf[pos + 3] << 4) | (buf[pos + 4] >> 4);
252 y2 = ((buf[pos + 4] & 0x0f) << 8) | buf[pos + 5];
256 av_log(NULL, AV_LOG_INFO, "x1=%d x2=%d y1=%d y2=%d\n",
262 if ((buf_size - pos) < 4)
264 offset1 = AV_RB16(buf + pos);
265 offset2 = AV_RB16(buf + pos + 2);
267 av_log(NULL, AV_LOG_INFO, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2);
272 if ((buf_size - pos) < 8)
274 offset1 = AV_RB32(buf + pos);
275 offset2 = AV_RB32(buf + pos + 4);
277 av_log(NULL, AV_LOG_INFO, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2);
284 if ((buf_size - pos) < 768)
286 yuv_palette = buf + pos;
290 /* HD set contrast (alpha) */
291 if ((buf_size - pos) < 256)
293 for (i = 0; i < 256; i++)
294 alpha[i] = 0xFF - buf[pos+i];
302 av_log(NULL, AV_LOG_INFO, "unrecognised subpicture command 0x%x\n", cmd);
312 /* decode the bitmap */
319 if (w > 0 && h > 0) {
320 if (sub_header->rects != NULL) {
321 for (i = 0; i < sub_header->num_rects; i++) {
322 av_free(sub_header->rects[i].bitmap);
323 av_free(sub_header->rects[i].rgba_palette);
325 av_freep(&sub_header->rects);
326 sub_header->num_rects = 0;
329 bitmap = av_malloc(w * h);
330 sub_header->rects = av_mallocz(sizeof(AVSubtitleRect));
331 sub_header->num_rects = 1;
332 sub_header->rects[0].bitmap = bitmap;
333 decode_rle(bitmap, w * 2, w, (h + 1) / 2,
334 buf, offset1, buf_size, is_8bit);
335 decode_rle(bitmap + w, w * 2, w, h / 2,
336 buf, offset2, buf_size, is_8bit);
338 if (yuv_palette == 0)
340 sub_header->rects[0].rgba_palette = av_malloc(256 * 4);
341 sub_header->rects[0].nb_colors = 256;
342 yuv_a_to_rgba(yuv_palette, alpha, sub_header->rects[0].rgba_palette, 256);
344 sub_header->rects[0].rgba_palette = av_malloc(4 * 4);
345 sub_header->rects[0].nb_colors = 4;
346 guess_palette(sub_header->rects[0].rgba_palette,
347 colormap, alpha, 0xffff00);
349 sub_header->rects[0].x = x1;
350 sub_header->rects[0].y = y1;
351 sub_header->rects[0].w = w;
352 sub_header->rects[0].h = h;
353 sub_header->rects[0].linesize = w;
356 if (next_cmd_pos == cmd_pos)
358 cmd_pos = next_cmd_pos;
360 if (sub_header->num_rects > 0)
363 if (sub_header->rects != NULL) {
364 for (i = 0; i < sub_header->num_rects; i++) {
365 av_free(sub_header->rects[i].bitmap);
366 av_free(sub_header->rects[i].rgba_palette);
368 av_freep(&sub_header->rects);
369 sub_header->num_rects = 0;
374 static int is_transp(const uint8_t *buf, int pitch, int n,
375 const uint8_t *transp_color)
378 for(i = 0; i < n; i++) {
379 if (!transp_color[*buf])
386 /* return 0 if empty rectangle, 1 if non empty */
387 static int find_smallest_bounding_rectangle(AVSubtitle *s)
389 uint8_t transp_color[256];
390 int y1, y2, x1, x2, y, w, h, i;
393 if (s->num_rects == 0 || s->rects == NULL || s->rects[0].w <= 0 || s->rects[0].h <= 0)
396 memset(transp_color, 0, 256);
397 for(i = 0; i < s->rects[0].nb_colors; i++) {
398 if ((s->rects[0].rgba_palette[i] >> 24) == 0)
402 while (y1 < s->rects[0].h && is_transp(s->rects[0].bitmap + y1 * s->rects[0].linesize,
403 1, s->rects[0].w, transp_color))
405 if (y1 == s->rects[0].h) {
406 av_freep(&s->rects[0].bitmap);
407 s->rects[0].w = s->rects[0].h = 0;
411 y2 = s->rects[0].h - 1;
412 while (y2 > 0 && is_transp(s->rects[0].bitmap + y2 * s->rects[0].linesize, 1,
413 s->rects[0].w, transp_color))
416 while (x1 < (s->rects[0].w - 1) && is_transp(s->rects[0].bitmap + x1, s->rects[0].linesize,
417 s->rects[0].h, transp_color))
419 x2 = s->rects[0].w - 1;
420 while (x2 > 0 && is_transp(s->rects[0].bitmap + x2, s->rects[0].linesize, s->rects[0].h,
425 bitmap = av_malloc(w * h);
428 for(y = 0; y < h; y++) {
429 memcpy(bitmap + w * y, s->rects[0].bitmap + x1 + (y1 + y) * s->rects[0].linesize, w);
431 av_freep(&s->rects[0].bitmap);
432 s->rects[0].bitmap = bitmap;
433 s->rects[0].linesize = w;
443 static void ppm_save(const char *filename, uint8_t *bitmap, int w, int h,
444 uint32_t *rgba_palette)
449 f = fopen(filename, "w");
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);
470 static int dvdsub_decode(AVCodecContext *avctx,
471 void *data, int *data_size,
472 const uint8_t *buf, int buf_size)
474 AVSubtitle *sub = (void *)data;
477 is_menu = decode_dvd_subtitles(sub, buf, buf_size);
485 if (!is_menu && find_smallest_bounding_rectangle(sub) == 0)
489 av_log(NULL, AV_LOG_INFO, "start=%d ms end =%d ms\n",
490 sub->start_display_time,
491 sub->end_display_time);
492 ppm_save("/tmp/a.ppm", sub->rects[0].bitmap,
493 sub->rects[0].w, sub->rects[0].h, sub->rects[0].rgba_palette);
500 AVCodec dvdsub_decoder = {
503 CODEC_ID_DVD_SUBTITLE,
509 .long_name = NULL_IF_CONFIG_SMALL("DVD subtitles"),