2 * DVD subtitle decoding
3 * Copyright (c) 2005 Fabrice Bellard
5 * This file is part of Libav.
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.
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.
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
26 #include "libavutil/attributes.h"
27 #include "libavutil/colorspace.h"
28 #include "libavutil/imgutils.h"
29 #include "libavutil/avstring.h"
31 typedef struct DVDSubContext {
36 static void yuv_a_to_rgba(const uint8_t *ycbcr, const uint8_t *alpha, uint32_t *rgba, int num_values)
38 const uint8_t *cm = ff_crop_tab + MAX_NEG_CROP;
41 int r_add, g_add, b_add;
43 for (i = num_values; i > 0; i--) {
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;
53 static int decode_run_2bit(GetBitContext *gb, int *color)
58 for (t = 1; v < t && t <= 0x40; t <<= 2)
59 v = (v << 4) | get_bits(gb, 4);
61 if (v < 4) { /* Code for fill rest of line */
67 static int decode_run_8bit(GetBitContext *gb, int *color)
70 int has_run = get_bits1(gb);
72 *color = get_bits(gb, 8);
74 *color = get_bits(gb, 2);
77 len = get_bits(gb, 7);
83 len = get_bits(gb, 3) + 2;
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)
97 bit_len = (buf_size - start) * 8;
98 init_get_bits(&gb, buf + start, bit_len);
104 if (get_bits_count(&gb) > bit_len)
107 len = decode_run_8bit(&gb, &color);
109 len = decode_run_2bit(&gb, &color);
110 len = FFMIN(len, w - x);
111 memset(d + x, color, len);
126 static void guess_palette(DVDSubContext* ctx,
127 uint32_t *rgba_palette,
130 uint32_t subtitle_color)
132 uint8_t color_used[16] = { 0 };
133 int nb_opaque_colors, i, level, j, r, g, b;
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);
142 for(i = 0; i < 4; i++)
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;
153 if (nb_opaque_colors == 0)
156 j = nb_opaque_colors;
157 memset(color_used, 0, 16);
158 for(i = 0; i < 4; i++) {
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);
169 rgba_palette[i] = (rgba_palette[color_used[colormap[i]] - 1] & 0x00ffffff) |
170 ((alpha[i] * 17) << 24);
176 #define READ_OFFSET(a) (big_offsets ? AV_RB32(a) : AV_RB16(a))
178 static int decode_dvd_subtitles(DVDSubContext *ctx, AVSubtitle *sub_header,
179 const uint8_t *buf, int buf_size)
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 };
191 memset(sub_header, 0, sizeof(*sub_header));
193 if (AV_RB16(buf) == 0) { /* HD subpicture with 4-byte offsets */
203 cmd_pos = READ_OFFSET(buf + cmd_pos);
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;
213 x1 = y1 = x2 = y2 = 0;
214 while (pos < buf_size) {
216 av_dlog(NULL, "cmd=%02x\n", cmd);
219 /* menu subpicture */
224 sub_header->start_display_time = (date << 10) / 90;
228 sub_header->end_display_time = (date << 10) / 90;
232 if ((buf_size - pos) < 2)
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;
242 if ((buf_size - pos) < 2)
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;
249 av_dlog(NULL, "alpha=%x%x%x%x\n", alpha[0],alpha[1],alpha[2],alpha[3]);
253 if ((buf_size - pos) < 6)
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];
261 av_dlog(NULL, "x1=%d x2=%d y1=%d y2=%d\n", x1, x2, y1, y2);
265 if ((buf_size - pos) < 4)
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);
273 if ((buf_size - pos) < 8)
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);
283 if ((buf_size - pos) < 768)
285 yuv_palette = buf + pos;
289 /* HD set contrast (alpha) */
290 if ((buf_size - pos) < 256)
292 for (i = 0; i < 256; i++)
293 alpha[i] = 0xFF - buf[pos+i];
300 av_dlog(NULL, "unrecognised subpicture command 0x%x\n", cmd);
309 /* decode the bitmap */
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]);
323 av_freep(&sub_header->rects);
324 sub_header->num_rects = 0;
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);
338 if (yuv_palette == 0)
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);
343 sub_header->rects[0]->nb_colors = 4;
345 (uint32_t*)sub_header->rects[0]->pict.data[1],
346 colormap, alpha, 0xffff00);
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;
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_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]);
369 av_freep(&sub_header->rects);
370 sub_header->num_rects = 0;
375 static int is_transp(const uint8_t *buf, int pitch, int n,
376 const uint8_t *transp_color)
379 for(i = 0; i < n; i++) {
380 if (!transp_color[*buf])
387 /* return 0 if empty rectangle, 1 if non empty */
388 static int find_smallest_bounding_rectangle(AVSubtitle *s)
390 uint8_t transp_color[256] = { 0 };
391 int y1, y2, x1, x2, y, w, h, i;
394 if (s->num_rects == 0 || s->rects == NULL || s->rects[0]->w <= 0 || s->rects[0]->h <= 0)
397 for(i = 0; i < s->rects[0]->nb_colors; i++) {
398 if ((((uint32_t*)s->rects[0]->pict.data[1])[i] >> 24) == 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))
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;
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))
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))
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,
425 bitmap = av_malloc(w * h);
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);
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;
436 s->rects[0]->x += x1;
437 s->rects[0]->y += y1;
442 static void ppm_save(const char *filename, uint8_t *bitmap, int w, int h,
443 uint32_t *rgba_palette)
448 f = fopen(filename, "w");
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);
469 static int dvdsub_decode(AVCodecContext *avctx,
470 void *data, int *data_size,
473 DVDSubContext *ctx = avctx->priv_data;
474 const uint8_t *buf = avpkt->data;
475 int buf_size = avpkt->size;
476 AVSubtitle *sub = data;
479 is_menu = decode_dvd_subtitles(ctx, sub, buf, buf_size);
487 if (!is_menu && find_smallest_bounding_rectangle(sub) == 0)
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]);
502 static av_cold int dvdsub_init(AVCodecContext *avctx)
504 DVDSubContext *ctx = avctx->priv_data;
507 if (!avctx->extradata || !avctx->extradata_size)
510 data = av_malloc(avctx->extradata_size + 1);
512 return AVERROR(ENOMEM);
513 memcpy(data, avctx->extradata, avctx->extradata_size);
514 data[avctx->extradata_size] = '\0';
518 if (strncmp("palette:", cur, 8) == 0) {
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))
527 } else if (!strncmp("size:", cur, 5)) {
529 if (sscanf(cur + 5, "%dx%d", &w, &h) == 2) {
530 int ret = ff_set_dimensions(avctx, w, h);
535 cur += strcspn(cur, "\n\r");
536 cur += strspn(cur, "\n\r");
542 AVCodec ff_dvdsub_decoder = {
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),
549 .decode = dvdsub_decode,