dac152b90f9b10c60047e4007fb5733920d5fffe
[ffmpeg.git] / libavcodec / dvdsubdec.c
1 /*
2  * DVD subtitle decoding for ffmpeg
3  * Copyright (c) 2005 Fabrice Bellard.
4  *
5  * This file is part of FFmpeg.
6  *
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.
11  *
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.
16  *
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
20  */
21 #include "avcodec.h"
22 #include "bitstream.h"
23 #include "colorspace.h"
24 #include "dsputil.h"
25
26 //#define DEBUG
27
28 static void yuv_a_to_rgba(const uint8_t *ycbcr, const uint8_t *alpha, uint32_t *rgba, int num_values)
29 {
30     uint8_t *cm = ff_cropTbl + MAX_NEG_CROP;
31     uint8_t r, g, b;
32     int i, y, cb, cr;
33     int r_add, g_add, b_add;
34
35     for (i = num_values; i > 0; i--) {
36         y = *ycbcr++;
37         cb = *ycbcr++;
38         cr = *ycbcr++;
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;
42     }
43 }
44
45 static int decode_run_2bit(GetBitContext *gb, int *color)
46 {
47     unsigned int v, t;
48
49     v = 0;
50     for (t = 1; v < t && t <= 0x40; t <<= 2)
51         v = (v << 4) | get_bits(gb, 4);
52     *color = v & 3;
53     if (v < 4) { /* Code for fill rest of line */
54         return INT_MAX;
55     }
56     return v >> 2;
57 }
58
59 static int decode_run_8bit(GetBitContext *gb, int *color)
60 {
61     int len;
62     int has_run = get_bits1(gb);
63     if (get_bits1(gb))
64         *color = get_bits(gb, 8);
65     else
66         *color = get_bits(gb, 2);
67     if (has_run) {
68         if (get_bits1(gb)) {
69             len = get_bits(gb, 7);
70             if (len == 0)
71                 len = INT_MAX;
72             else
73                 len += 9;
74         } else
75             len = get_bits(gb, 3) + 2;
76     } else
77         len = 1;
78     return len;
79 }
80
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)
83 {
84     GetBitContext gb;
85     int bit_len;
86     int x, y, len, color;
87     uint8_t *d;
88
89     bit_len = (buf_size - start) * 8;
90     init_get_bits(&gb, buf + start, bit_len);
91
92     x = 0;
93     y = 0;
94     d = bitmap;
95     for(;;) {
96         if (get_bits_count(&gb) > bit_len)
97             return -1;
98         if (is_8bit)
99             len = decode_run_8bit(&gb, &color);
100         else
101             len = decode_run_2bit(&gb, &color);
102         len = FFMIN(len, w - x);
103         memset(d + x, color, len);
104         x += len;
105         if (x >= w) {
106             y++;
107             if (y >= h)
108                 break;
109             d += linesize;
110             x = 0;
111             /* byte align */
112             align_get_bits(&gb);
113         }
114     }
115     return 0;
116 }
117
118 static void guess_palette(uint32_t *rgba_palette,
119                           uint8_t *colormap,
120                           uint8_t *alpha,
121                           uint32_t subtitle_color)
122 {
123     uint8_t color_used[16];
124     int nb_opaque_colors, i, level, j, r, g, b;
125
126     for(i = 0; i < 4; i++)
127         rgba_palette[i] = 0;
128
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;
134             nb_opaque_colors++;
135         }
136     }
137
138     if (nb_opaque_colors == 0)
139         return;
140
141     j = nb_opaque_colors;
142     memset(color_used, 0, 16);
143     for(i = 0; i < 4; i++) {
144         if (alpha[i] != 0) {
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);
152                 j--;
153             } else {
154                 rgba_palette[i] = (rgba_palette[color_used[colormap[i]] - 1] & 0x00ffffff) |
155                                     ((alpha[i] * 17) << 24);
156             }
157         }
158     }
159 }
160
161 #define READ_OFFSET(a) (big_offsets ? AV_RB32(a) : AV_RB16(a))
162
163 static int decode_dvd_subtitles(AVSubtitle *sub_header,
164                                 const uint8_t *buf, int buf_size)
165 {
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];
170     int date;
171     int i;
172     int is_menu = 0;
173
174     if (buf_size < 10)
175         return -1;
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;
180
181     if (AV_RB16(buf) == 0) {   /* HD subpicture with 4-byte offsets */
182         big_offsets = 1;
183         offset_size = 4;
184         cmd_pos = 6;
185     } else {
186         big_offsets = 0;
187         offset_size = 2;
188         cmd_pos = 2;
189     }
190
191     cmd_pos = READ_OFFSET(buf + cmd_pos);
192
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);
196 #ifdef DEBUG
197         av_log(NULL, AV_LOG_INFO, "cmd_pos=0x%04x next=0x%04x date=%d\n",
198                cmd_pos, next_cmd_pos, date);
199 #endif
200         pos = cmd_pos + 2 + offset_size;
201         offset1 = -1;
202         offset2 = -1;
203         x1 = y1 = x2 = y2 = 0;
204         while (pos < buf_size) {
205             cmd = buf[pos++];
206 #ifdef DEBUG
207             av_log(NULL, AV_LOG_INFO, "cmd=%02x\n", cmd);
208 #endif
209             switch(cmd) {
210             case 0x00:
211                 /* menu subpicture */
212                 is_menu = 1;
213                 break;
214             case 0x01:
215                 /* set start date */
216                 sub_header->start_display_time = (date << 10) / 90;
217                 break;
218             case 0x02:
219                 /* set end date */
220                 sub_header->end_display_time = (date << 10) / 90;
221                 break;
222             case 0x03:
223                 /* set colormap */
224                 if ((buf_size - pos) < 2)
225                     goto fail;
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;
230                 pos += 2;
231                 break;
232             case 0x04:
233                 /* set alpha */
234                 if ((buf_size - pos) < 2)
235                     goto fail;
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;
240                 pos += 2;
241 #ifdef DEBUG
242             av_log(NULL, AV_LOG_INFO, "alpha=%x%x%x%x\n", alpha[0],alpha[1],alpha[2],alpha[3]);
243 #endif
244                 break;
245             case 0x05:
246             case 0x85:
247                 if ((buf_size - pos) < 6)
248                     goto fail;
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];
253                 if (cmd & 0x80)
254                     is_8bit = 1;
255 #ifdef DEBUG
256                 av_log(NULL, AV_LOG_INFO, "x1=%d x2=%d y1=%d y2=%d\n",
257                        x1, x2, y1, y2);
258 #endif
259                 pos += 6;
260                 break;
261             case 0x06:
262                 if ((buf_size - pos) < 4)
263                     goto fail;
264                 offset1 = AV_RB16(buf + pos);
265                 offset2 = AV_RB16(buf + pos + 2);
266 #ifdef DEBUG
267                 av_log(NULL, AV_LOG_INFO, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2);
268 #endif
269                 pos += 4;
270                 break;
271             case 0x86:
272                 if ((buf_size - pos) < 8)
273                     goto fail;
274                 offset1 = AV_RB32(buf + pos);
275                 offset2 = AV_RB32(buf + pos + 4);
276 #ifdef DEBUG
277                 av_log(NULL, AV_LOG_INFO, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2);
278 #endif
279                 pos += 8;
280                 break;
281
282             case 0x83:
283                 /* HD set palette */
284                 if ((buf_size - pos) < 768)
285                     goto fail;
286                 yuv_palette = buf + pos;
287                 pos += 768;
288                 break;
289             case 0x84:
290                 /* HD set contrast (alpha) */
291                 if ((buf_size - pos) < 256)
292                     goto fail;
293                 for (i = 0; i < 256; i++)
294                     alpha[i] = 0xFF - buf[pos+i];
295                 pos += 256;
296                 break;
297
298             case 0xff:
299                 goto the_end;
300             default:
301 #ifdef DEBUG
302                 av_log(NULL, AV_LOG_INFO, "unrecognised subpicture command 0x%x\n", cmd);
303 #endif
304                 goto the_end;
305             }
306         }
307     the_end:
308         if (offset1 >= 0) {
309             int w, h;
310             uint8_t *bitmap;
311
312             /* decode the bitmap */
313             w = x2 - x1 + 1;
314             if (w < 0)
315                 w = 0;
316             h = y2 - y1;
317             if (h < 0)
318                 h = 0;
319             if (w > 0 && h > 0) {
320                 if (sub_header->rects != NULL) {
321                     for (i = 0; i < sub_header->num_rects; i++) {
322                         av_freep(&sub_header->rects[i]->pict.data[0]);
323                         av_freep(&sub_header->rects[i]->pict.data[1]);
324                         av_freep(&sub_header->rects[i]);
325                     }
326                     av_freep(&sub_header->rects);
327                     sub_header->num_rects = 0;
328                 }
329
330                 bitmap = av_malloc(w * h);
331                 sub_header->rects = av_mallocz(sizeof(*sub_header->rects));
332                 sub_header->rects[0] = av_mallocz(sizeof(AVSubtitleRect));
333                 sub_header->num_rects = 1;
334                 sub_header->rects[0]->pict.data[0] = bitmap;
335                 decode_rle(bitmap, w * 2, w, (h + 1) / 2,
336                            buf, offset1, buf_size, is_8bit);
337                 decode_rle(bitmap + w, w * 2, w, h / 2,
338                            buf, offset2, buf_size, is_8bit);
339                 if (is_8bit) {
340                     if (yuv_palette == 0)
341                         goto fail;
342                     sub_header->rects[0]->pict.data[1] = av_malloc(256 * 4);
343                     sub_header->rects[0]->nb_colors = 256;
344                     yuv_a_to_rgba(yuv_palette, alpha, (uint32_t*)sub_header->rects[0]->pict.data[1], 256);
345                 } else {
346                     sub_header->rects[0]->pict.data[1] = av_malloc(4 * 4);
347                     sub_header->rects[0]->nb_colors = 4;
348                     guess_palette((uint32_t*)sub_header->rects[0]->pict.data[1],
349                                   colormap, alpha, 0xffff00);
350                 }
351                 sub_header->rects[0]->x = x1;
352                 sub_header->rects[0]->y = y1;
353                 sub_header->rects[0]->w = w;
354                 sub_header->rects[0]->h = h;
355                 sub_header->rects[0]->pict.linesize[0] = w;
356             }
357         }
358         if (next_cmd_pos == cmd_pos)
359             break;
360         cmd_pos = next_cmd_pos;
361     }
362     if (sub_header->num_rects > 0)
363         return is_menu;
364  fail:
365     if (sub_header->rects != NULL) {
366         for (i = 0; i < sub_header->num_rects; i++) {
367             av_freep(&sub_header->rects[i]->pict.data[0]);
368             av_freep(&sub_header->rects[i]->pict.data[1]);
369             av_freep(&sub_header->rects[i]);
370         }
371         av_freep(&sub_header->rects);
372         sub_header->num_rects = 0;
373     }
374     return -1;
375 }
376
377 static int is_transp(const uint8_t *buf, int pitch, int n,
378                      const uint8_t *transp_color)
379 {
380     int i;
381     for(i = 0; i < n; i++) {
382         if (!transp_color[*buf])
383             return 0;
384         buf += pitch;
385     }
386     return 1;
387 }
388
389 /* return 0 if empty rectangle, 1 if non empty */
390 static int find_smallest_bounding_rectangle(AVSubtitle *s)
391 {
392     uint8_t transp_color[256];
393     int y1, y2, x1, x2, y, w, h, i;
394     uint8_t *bitmap;
395
396     if (s->num_rects == 0 || s->rects == NULL || s->rects[0]->w <= 0 || s->rects[0]->h <= 0)
397         return 0;
398
399     memset(transp_color, 0, 256);
400     for(i = 0; i < s->rects[0]->nb_colors; i++) {
401         if ((((uint32_t*)s->rects[0]->pict.data[1])[i] >> 24) == 0)
402             transp_color[i] = 1;
403     }
404     y1 = 0;
405     while (y1 < s->rects[0]->h && is_transp(s->rects[0]->pict.data[0] + y1 * s->rects[0]->pict.linesize[0],
406                                   1, s->rects[0]->w, transp_color))
407         y1++;
408     if (y1 == s->rects[0]->h) {
409         av_freep(&s->rects[0]->pict.data[0]);
410         s->rects[0]->w = s->rects[0]->h = 0;
411         return 0;
412     }
413
414     y2 = s->rects[0]->h - 1;
415     while (y2 > 0 && is_transp(s->rects[0]->pict.data[0] + y2 * s->rects[0]->pict.linesize[0], 1,
416                                s->rects[0]->w, transp_color))
417         y2--;
418     x1 = 0;
419     while (x1 < (s->rects[0]->w - 1) && is_transp(s->rects[0]->pict.data[0] + x1, s->rects[0]->pict.linesize[0],
420                                         s->rects[0]->h, transp_color))
421         x1++;
422     x2 = s->rects[0]->w - 1;
423     while (x2 > 0 && is_transp(s->rects[0]->pict.data[0] + x2, s->rects[0]->pict.linesize[0], s->rects[0]->h,
424                                   transp_color))
425         x2--;
426     w = x2 - x1 + 1;
427     h = y2 - y1 + 1;
428     bitmap = av_malloc(w * h);
429     if (!bitmap)
430         return 1;
431     for(y = 0; y < h; y++) {
432         memcpy(bitmap + w * y, s->rects[0]->pict.data[0] + x1 + (y1 + y) * s->rects[0]->pict.linesize[0], w);
433     }
434     av_freep(&s->rects[0]->pict.data[0]);
435     s->rects[0]->pict.data[0] = bitmap;
436     s->rects[0]->pict.linesize[0] = w;
437     s->rects[0]->w = w;
438     s->rects[0]->h = h;
439     s->rects[0]->x += x1;
440     s->rects[0]->y += y1;
441     return 1;
442 }
443
444 #ifdef DEBUG
445 #undef fprintf
446 #undef perror
447 #undef exit
448 static void ppm_save(const char *filename, uint8_t *bitmap, int w, int h,
449                      uint32_t *rgba_palette)
450 {
451     int x, y, v;
452     FILE *f;
453
454     f = fopen(filename, "w");
455     if (!f) {
456         perror(filename);
457         exit(1);
458     }
459     fprintf(f, "P6\n"
460             "%d %d\n"
461             "%d\n",
462             w, h, 255);
463     for(y = 0; y < h; y++) {
464         for(x = 0; x < w; x++) {
465             v = rgba_palette[bitmap[y * w + x]];
466             putc((v >> 16) & 0xff, f);
467             putc((v >> 8) & 0xff, f);
468             putc((v >> 0) & 0xff, f);
469         }
470     }
471     fclose(f);
472 }
473 #endif
474
475 static int dvdsub_decode(AVCodecContext *avctx,
476                          void *data, int *data_size,
477                          const uint8_t *buf, int buf_size)
478 {
479     AVSubtitle *sub = (void *)data;
480     int is_menu;
481
482     is_menu = decode_dvd_subtitles(sub, buf, buf_size);
483
484     if (is_menu < 0) {
485     no_subtitle:
486         *data_size = 0;
487
488         return buf_size;
489     }
490     if (!is_menu && find_smallest_bounding_rectangle(sub) == 0)
491         goto no_subtitle;
492
493 #if defined(DEBUG)
494     av_log(NULL, AV_LOG_INFO, "start=%d ms end =%d ms\n",
495            sub->start_display_time,
496            sub->end_display_time);
497     ppm_save("/tmp/a.ppm", sub->rects[0]->pict.data[0],
498              sub->rects[0]->w, sub->rects[0]->h, sub->rects[0]->pict.data[1]);
499 #endif
500
501     *data_size = 1;
502     return buf_size;
503 }
504
505 AVCodec dvdsub_decoder = {
506     "dvdsub",
507     CODEC_TYPE_SUBTITLE,
508     CODEC_ID_DVD_SUBTITLE,
509     0,
510     NULL,
511     NULL,
512     NULL,
513     dvdsub_decode,
514     .long_name = NULL_IF_CONFIG_SMALL("DVD subtitles"),
515 };