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
24 #include "libavutil/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 static const uint8_t level_map[4][4] = {
124 // this configuration (full range, lowest to highest) in tests
125 // seemed most common, so assume this
129 {0x00, 0x55, 0xaa, 0xff},
131 uint8_t color_used[16];
132 int nb_opaque_colors, i, level, j, r, g, b;
134 for(i = 0; i < 4; i++)
137 memset(color_used, 0, 16);
138 nb_opaque_colors = 0;
139 for(i = 0; i < 4; i++) {
140 if (alpha[i] != 0 && !color_used[colormap[i]]) {
141 color_used[colormap[i]] = 1;
146 if (nb_opaque_colors == 0)
150 memset(color_used, 0, 16);
151 for(i = 0; i < 4; i++) {
153 if (!color_used[colormap[i]]) {
154 level = level_map[nb_opaque_colors][j];
155 r = (((subtitle_color >> 16) & 0xff) * level) >> 8;
156 g = (((subtitle_color >> 8) & 0xff) * level) >> 8;
157 b = (((subtitle_color >> 0) & 0xff) * level) >> 8;
158 rgba_palette[i] = b | (g << 8) | (r << 16) | ((alpha[i] * 17) << 24);
159 color_used[colormap[i]] = (i + 1);
162 rgba_palette[i] = (rgba_palette[color_used[colormap[i]] - 1] & 0x00ffffff) |
163 ((alpha[i] * 17) << 24);
169 #define READ_OFFSET(a) (big_offsets ? AV_RB32(a) : AV_RB16(a))
171 static int decode_dvd_subtitles(AVSubtitle *sub_header,
172 const uint8_t *buf, int buf_size)
174 int cmd_pos, pos, cmd, x1, y1, x2, y2, offset1, offset2, next_cmd_pos;
175 int big_offsets, offset_size, is_8bit = 0;
176 const uint8_t *yuv_palette = 0;
177 uint8_t colormap[4], alpha[256];
185 if (AV_RB16(buf) == 0) { /* HD subpicture with 4-byte offsets */
195 cmd_pos = READ_OFFSET(buf + cmd_pos);
197 while (cmd_pos > 0 && cmd_pos < buf_size - 2 - offset_size) {
198 date = AV_RB16(buf + cmd_pos);
199 next_cmd_pos = READ_OFFSET(buf + cmd_pos + 2);
200 av_dlog(NULL, "cmd_pos=0x%04x next=0x%04x date=%d\n",
201 cmd_pos, next_cmd_pos, date);
202 pos = cmd_pos + 2 + offset_size;
205 x1 = y1 = x2 = y2 = 0;
206 while (pos < buf_size) {
208 av_dlog(NULL, "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;
241 av_dlog(NULL, "alpha=%x%x%x%x\n", alpha[0],alpha[1],alpha[2],alpha[3]);
245 if ((buf_size - pos) < 6)
247 x1 = (buf[pos] << 4) | (buf[pos + 1] >> 4);
248 x2 = ((buf[pos + 1] & 0x0f) << 8) | buf[pos + 2];
249 y1 = (buf[pos + 3] << 4) | (buf[pos + 4] >> 4);
250 y2 = ((buf[pos + 4] & 0x0f) << 8) | buf[pos + 5];
253 av_dlog(NULL, "x1=%d x2=%d y1=%d y2=%d\n", x1, x2, y1, y2);
257 if ((buf_size - pos) < 4)
259 offset1 = AV_RB16(buf + pos);
260 offset2 = AV_RB16(buf + pos + 2);
261 av_dlog(NULL, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2);
265 if ((buf_size - pos) < 8)
267 offset1 = AV_RB32(buf + pos);
268 offset2 = AV_RB32(buf + pos + 4);
269 av_dlog(NULL, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2);
275 if ((buf_size - pos) < 768)
277 yuv_palette = buf + pos;
281 /* HD set contrast (alpha) */
282 if ((buf_size - pos) < 256)
284 for (i = 0; i < 256; i++)
285 alpha[i] = 0xFF - buf[pos+i];
292 av_dlog(NULL, "unrecognised subpicture command 0x%x\n", cmd);
301 /* decode the bitmap */
308 if (w > 0 && h > 0) {
309 if (sub_header->rects != NULL) {
310 for (i = 0; i < sub_header->num_rects; i++) {
311 av_freep(&sub_header->rects[i]->pict.data[0]);
312 av_freep(&sub_header->rects[i]->pict.data[1]);
313 av_freep(&sub_header->rects[i]);
315 av_freep(&sub_header->rects);
316 sub_header->num_rects = 0;
319 bitmap = av_malloc(w * h);
320 sub_header->rects = av_mallocz(sizeof(*sub_header->rects));
321 sub_header->rects[0] = av_mallocz(sizeof(AVSubtitleRect));
322 sub_header->num_rects = 1;
323 sub_header->rects[0]->pict.data[0] = bitmap;
324 decode_rle(bitmap, w * 2, w, (h + 1) / 2,
325 buf, offset1, buf_size, is_8bit);
326 decode_rle(bitmap + w, w * 2, w, h / 2,
327 buf, offset2, buf_size, is_8bit);
328 sub_header->rects[0]->pict.data[1] = av_mallocz(AVPALETTE_SIZE);
330 if (yuv_palette == 0)
332 sub_header->rects[0]->nb_colors = 256;
333 yuv_a_to_rgba(yuv_palette, alpha, (uint32_t*)sub_header->rects[0]->pict.data[1], 256);
335 sub_header->rects[0]->nb_colors = 4;
336 guess_palette((uint32_t*)sub_header->rects[0]->pict.data[1],
337 colormap, alpha, 0xffff00);
339 sub_header->rects[0]->x = x1;
340 sub_header->rects[0]->y = y1;
341 sub_header->rects[0]->w = w;
342 sub_header->rects[0]->h = h;
343 sub_header->rects[0]->type = SUBTITLE_BITMAP;
344 sub_header->rects[0]->pict.linesize[0] = w;
347 if (next_cmd_pos == cmd_pos)
349 cmd_pos = next_cmd_pos;
351 if (sub_header->num_rects > 0)
354 if (sub_header->rects != NULL) {
355 for (i = 0; i < sub_header->num_rects; i++) {
356 av_freep(&sub_header->rects[i]->pict.data[0]);
357 av_freep(&sub_header->rects[i]->pict.data[1]);
358 av_freep(&sub_header->rects[i]);
360 av_freep(&sub_header->rects);
361 sub_header->num_rects = 0;
366 static int is_transp(const uint8_t *buf, int pitch, int n,
367 const uint8_t *transp_color)
370 for(i = 0; i < n; i++) {
371 if (!transp_color[*buf])
378 /* return 0 if empty rectangle, 1 if non empty */
379 static int find_smallest_bounding_rectangle(AVSubtitle *s)
381 uint8_t transp_color[256];
382 int y1, y2, x1, x2, y, w, h, i;
385 if (s->num_rects == 0 || s->rects == NULL || s->rects[0]->w <= 0 || s->rects[0]->h <= 0)
388 memset(transp_color, 0, 256);
389 for(i = 0; i < s->rects[0]->nb_colors; i++) {
390 if ((((uint32_t*)s->rects[0]->pict.data[1])[i] >> 24) == 0)
394 while (y1 < s->rects[0]->h && is_transp(s->rects[0]->pict.data[0] + y1 * s->rects[0]->pict.linesize[0],
395 1, s->rects[0]->w, transp_color))
397 if (y1 == s->rects[0]->h) {
398 av_freep(&s->rects[0]->pict.data[0]);
399 s->rects[0]->w = s->rects[0]->h = 0;
403 y2 = s->rects[0]->h - 1;
404 while (y2 > 0 && is_transp(s->rects[0]->pict.data[0] + y2 * s->rects[0]->pict.linesize[0], 1,
405 s->rects[0]->w, transp_color))
408 while (x1 < (s->rects[0]->w - 1) && is_transp(s->rects[0]->pict.data[0] + x1, s->rects[0]->pict.linesize[0],
409 s->rects[0]->h, transp_color))
411 x2 = s->rects[0]->w - 1;
412 while (x2 > 0 && is_transp(s->rects[0]->pict.data[0] + x2, s->rects[0]->pict.linesize[0], s->rects[0]->h,
417 bitmap = av_malloc(w * h);
420 for(y = 0; y < h; y++) {
421 memcpy(bitmap + w * y, s->rects[0]->pict.data[0] + x1 + (y1 + y) * s->rects[0]->pict.linesize[0], w);
423 av_freep(&s->rects[0]->pict.data[0]);
424 s->rects[0]->pict.data[0] = bitmap;
425 s->rects[0]->pict.linesize[0] = w;
428 s->rects[0]->x += x1;
429 s->rects[0]->y += y1;
437 static void ppm_save(const char *filename, uint8_t *bitmap, int w, int h,
438 uint32_t *rgba_palette)
443 f = fopen(filename, "w");
452 for(y = 0; y < h; y++) {
453 for(x = 0; x < w; x++) {
454 v = rgba_palette[bitmap[y * w + x]];
455 putc((v >> 16) & 0xff, f);
456 putc((v >> 8) & 0xff, f);
457 putc((v >> 0) & 0xff, f);
464 static int dvdsub_decode(AVCodecContext *avctx,
465 void *data, int *data_size,
468 const uint8_t *buf = avpkt->data;
469 int buf_size = avpkt->size;
470 AVSubtitle *sub = data;
473 is_menu = decode_dvd_subtitles(sub, buf, buf_size);
481 if (!is_menu && find_smallest_bounding_rectangle(sub) == 0)
485 av_dlog(NULL, "start=%d ms end =%d ms\n",
486 sub->start_display_time,
487 sub->end_display_time);
488 ppm_save("/tmp/a.ppm", sub->rects[0]->pict.data[0],
489 sub->rects[0]->w, sub->rects[0]->h, sub->rects[0]->pict.data[1]);
496 AVCodec ff_dvdsub_decoder = {
498 AVMEDIA_TYPE_SUBTITLE,
499 CODEC_ID_DVD_SUBTITLE,
505 .long_name = NULL_IF_CONFIG_SMALL("DVD subtitles"),