xref: /third_party/ffmpeg/libavcodec/dvbsubdec.c (revision cabdff1a)
1/*
2 * DVB subtitle decoding
3 * Copyright (c) 2005 Ian Caulfield
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
22#include "avcodec.h"
23#include "get_bits.h"
24#include "bytestream.h"
25#include "codec_internal.h"
26#include "internal.h"
27#include "libavutil/colorspace.h"
28#include "libavutil/imgutils.h"
29#include "libavutil/opt.h"
30#include "libavutil/thread.h"
31
32#define DVBSUB_PAGE_SEGMENT     0x10
33#define DVBSUB_REGION_SEGMENT   0x11
34#define DVBSUB_CLUT_SEGMENT     0x12
35#define DVBSUB_OBJECT_SEGMENT   0x13
36#define DVBSUB_DISPLAYDEFINITION_SEGMENT 0x14
37#define DVBSUB_DISPLAY_SEGMENT  0x80
38
39#define cm (ff_crop_tab + MAX_NEG_CROP)
40
41#define RGBA(r,g,b,a) (((unsigned)(a) << 24) | ((r) << 16) | ((g) << 8) | (b))
42
43typedef struct DVBSubCLUT {
44    int id;
45    int version;
46
47    uint32_t clut4[4];
48    uint32_t clut16[16];
49    uint32_t clut256[256];
50
51    struct DVBSubCLUT *next;
52} DVBSubCLUT;
53
54static DVBSubCLUT default_clut;
55
56typedef struct DVBSubObjectDisplay {
57    int object_id;
58    int region_id;
59
60    int x_pos;
61    int y_pos;
62
63    int fgcolor;
64    int bgcolor;
65
66    struct DVBSubObjectDisplay *region_list_next;
67    struct DVBSubObjectDisplay *object_list_next;
68} DVBSubObjectDisplay;
69
70typedef struct DVBSubObject {
71    int id;
72    int version;
73
74    int type;
75
76    DVBSubObjectDisplay *display_list;
77
78    struct DVBSubObject *next;
79} DVBSubObject;
80
81typedef struct DVBSubRegionDisplay {
82    int region_id;
83
84    int x_pos;
85    int y_pos;
86
87    struct DVBSubRegionDisplay *next;
88} DVBSubRegionDisplay;
89
90typedef struct DVBSubRegion {
91    int id;
92    int version;
93
94    int width;
95    int height;
96    int depth;
97
98    int clut;
99    int bgcolor;
100
101    uint8_t computed_clut[4*256];
102    int has_computed_clut;
103
104    uint8_t *pbuf;
105    int buf_size;
106    int dirty;
107
108    DVBSubObjectDisplay *display_list;
109
110    struct DVBSubRegion *next;
111} DVBSubRegion;
112
113typedef struct DVBSubDisplayDefinition {
114    int version;
115
116    int x;
117    int y;
118    int width;
119    int height;
120} DVBSubDisplayDefinition;
121
122typedef struct DVBSubContext {
123    AVClass *class;
124    int composition_id;
125    int ancillary_id;
126
127    int version;
128    int time_out;
129    int compute_edt; /**< if 1 end display time calculated using pts
130                          if 0 (Default) calculated using time out */
131    int compute_clut;
132    int clut_count2[257][256];
133    int substream;
134    int64_t prev_start;
135    DVBSubRegion *region_list;
136    DVBSubCLUT   *clut_list;
137    DVBSubObject *object_list;
138
139    DVBSubRegionDisplay *display_list;
140    DVBSubDisplayDefinition *display_definition;
141} DVBSubContext;
142
143
144static DVBSubObject* get_object(DVBSubContext *ctx, int object_id)
145{
146    DVBSubObject *ptr = ctx->object_list;
147
148    while (ptr && ptr->id != object_id) {
149        ptr = ptr->next;
150    }
151
152    return ptr;
153}
154
155static DVBSubCLUT* get_clut(DVBSubContext *ctx, int clut_id)
156{
157    DVBSubCLUT *ptr = ctx->clut_list;
158
159    while (ptr && ptr->id != clut_id) {
160        ptr = ptr->next;
161    }
162
163    return ptr;
164}
165
166static DVBSubRegion* get_region(DVBSubContext *ctx, int region_id)
167{
168    DVBSubRegion *ptr = ctx->region_list;
169
170    while (ptr && ptr->id != region_id) {
171        ptr = ptr->next;
172    }
173
174    return ptr;
175}
176
177static void delete_region_display_list(DVBSubContext *ctx, DVBSubRegion *region)
178{
179    DVBSubObject *object, *obj2, **obj2_ptr;
180    DVBSubObjectDisplay *display, *obj_disp, **obj_disp_ptr;
181
182    while (region->display_list) {
183        display = region->display_list;
184
185        object = get_object(ctx, display->object_id);
186
187        if (object) {
188            obj_disp_ptr = &object->display_list;
189            obj_disp = *obj_disp_ptr;
190
191            while (obj_disp && obj_disp != display) {
192                obj_disp_ptr = &obj_disp->object_list_next;
193                obj_disp = *obj_disp_ptr;
194            }
195
196            if (obj_disp) {
197                *obj_disp_ptr = obj_disp->object_list_next;
198
199                if (!object->display_list) {
200                    obj2_ptr = &ctx->object_list;
201                    obj2 = *obj2_ptr;
202
203                    while (obj2 != object) {
204                        av_assert0(obj2);
205                        obj2_ptr = &obj2->next;
206                        obj2 = *obj2_ptr;
207                    }
208
209                    *obj2_ptr = obj2->next;
210
211                    av_freep(&obj2);
212                }
213            }
214        }
215
216        region->display_list = display->region_list_next;
217
218        av_freep(&display);
219    }
220
221}
222
223static void delete_cluts(DVBSubContext *ctx)
224{
225    while (ctx->clut_list) {
226        DVBSubCLUT *clut = ctx->clut_list;
227
228        ctx->clut_list = clut->next;
229
230        av_freep(&clut);
231    }
232}
233
234static void delete_objects(DVBSubContext *ctx)
235{
236    while (ctx->object_list) {
237        DVBSubObject *object = ctx->object_list;
238
239        ctx->object_list = object->next;
240
241        av_freep(&object);
242    }
243}
244
245static void delete_regions(DVBSubContext *ctx)
246{
247    while (ctx->region_list) {
248        DVBSubRegion *region = ctx->region_list;
249
250        ctx->region_list = region->next;
251
252        delete_region_display_list(ctx, region);
253
254        av_freep(&region->pbuf);
255        av_freep(&region);
256    }
257}
258
259static av_cold void init_default_clut(void)
260{
261    int i, r, g, b, a = 0;
262
263    default_clut.id = -1;
264    default_clut.next = NULL;
265
266    default_clut.clut4[0] = RGBA(  0,   0,   0,   0);
267    default_clut.clut4[1] = RGBA(255, 255, 255, 255);
268    default_clut.clut4[2] = RGBA(  0,   0,   0, 255);
269    default_clut.clut4[3] = RGBA(127, 127, 127, 255);
270
271    default_clut.clut16[0] = RGBA(  0,   0,   0,   0);
272    for (i = 1; i < 16; i++) {
273        if (i < 8) {
274            r = (i & 1) ? 255 : 0;
275            g = (i & 2) ? 255 : 0;
276            b = (i & 4) ? 255 : 0;
277        } else {
278            r = (i & 1) ? 127 : 0;
279            g = (i & 2) ? 127 : 0;
280            b = (i & 4) ? 127 : 0;
281        }
282        default_clut.clut16[i] = RGBA(r, g, b, 255);
283    }
284
285    default_clut.clut256[0] = RGBA(  0,   0,   0,   0);
286    for (i = 1; i < 256; i++) {
287        if (i < 8) {
288            r = (i & 1) ? 255 : 0;
289            g = (i & 2) ? 255 : 0;
290            b = (i & 4) ? 255 : 0;
291            a = 63;
292        } else {
293            switch (i & 0x88) {
294            case 0x00:
295                r = ((i & 1) ? 85 : 0) + ((i & 0x10) ? 170 : 0);
296                g = ((i & 2) ? 85 : 0) + ((i & 0x20) ? 170 : 0);
297                b = ((i & 4) ? 85 : 0) + ((i & 0x40) ? 170 : 0);
298                a = 255;
299                break;
300            case 0x08:
301                r = ((i & 1) ? 85 : 0) + ((i & 0x10) ? 170 : 0);
302                g = ((i & 2) ? 85 : 0) + ((i & 0x20) ? 170 : 0);
303                b = ((i & 4) ? 85 : 0) + ((i & 0x40) ? 170 : 0);
304                a = 127;
305                break;
306            case 0x80:
307                r = 127 + ((i & 1) ? 43 : 0) + ((i & 0x10) ? 85 : 0);
308                g = 127 + ((i & 2) ? 43 : 0) + ((i & 0x20) ? 85 : 0);
309                b = 127 + ((i & 4) ? 43 : 0) + ((i & 0x40) ? 85 : 0);
310                a = 255;
311                break;
312            case 0x88:
313                r = ((i & 1) ? 43 : 0) + ((i & 0x10) ? 85 : 0);
314                g = ((i & 2) ? 43 : 0) + ((i & 0x20) ? 85 : 0);
315                b = ((i & 4) ? 43 : 0) + ((i & 0x40) ? 85 : 0);
316                a = 255;
317                break;
318            }
319        }
320        default_clut.clut256[i] = RGBA(r, g, b, a);
321    }
322}
323
324static av_cold int dvbsub_init_decoder(AVCodecContext *avctx)
325{
326    static AVOnce init_static_once = AV_ONCE_INIT;
327    DVBSubContext *ctx = avctx->priv_data;
328
329    if (ctx->substream < 0) {
330        ctx->composition_id = -1;
331        ctx->ancillary_id   = -1;
332    } else if (!avctx->extradata || (avctx->extradata_size < 4) || ((avctx->extradata_size % 5 != 0) && (avctx->extradata_size != 4))) {
333        av_log(avctx, AV_LOG_WARNING, "Invalid DVB subtitles stream extradata!\n");
334        ctx->composition_id = -1;
335        ctx->ancillary_id   = -1;
336    } else {
337        if (avctx->extradata_size > 5*ctx->substream + 2) {
338            ctx->composition_id = AV_RB16(avctx->extradata + 5*ctx->substream);
339            ctx->ancillary_id   = AV_RB16(avctx->extradata + 5*ctx->substream + 2);
340        } else {
341            av_log(avctx, AV_LOG_WARNING, "Selected DVB subtitles sub-stream %d is not available\n", ctx->substream);
342            ctx->composition_id = AV_RB16(avctx->extradata);
343            ctx->ancillary_id   = AV_RB16(avctx->extradata + 2);
344        }
345    }
346
347    ctx->version = -1;
348    ctx->prev_start = AV_NOPTS_VALUE;
349
350    ff_thread_once(&init_static_once, init_default_clut);
351
352    return 0;
353}
354
355static av_cold int dvbsub_close_decoder(AVCodecContext *avctx)
356{
357    DVBSubContext *ctx = avctx->priv_data;
358    DVBSubRegionDisplay *display;
359
360    delete_regions(ctx);
361
362    delete_objects(ctx);
363
364    delete_cluts(ctx);
365
366    av_freep(&ctx->display_definition);
367
368    while (ctx->display_list) {
369        display = ctx->display_list;
370        ctx->display_list = display->next;
371
372        av_freep(&display);
373    }
374
375    return 0;
376}
377
378static int dvbsub_read_2bit_string(AVCodecContext *avctx,
379                                   uint8_t *destbuf, int dbuf_len,
380                                   const uint8_t **srcbuf, int buf_size,
381                                   int non_mod, uint8_t *map_table, int x_pos)
382{
383    GetBitContext gb;
384
385    int bits;
386    int run_length;
387    int pixels_read = x_pos;
388
389    init_get_bits(&gb, *srcbuf, buf_size << 3);
390
391    destbuf += x_pos;
392
393    while (get_bits_count(&gb) < buf_size << 3 && pixels_read < dbuf_len) {
394        bits = get_bits(&gb, 2);
395
396        if (bits) {
397            if (non_mod != 1 || bits != 1) {
398                if (map_table)
399                    *destbuf++ = map_table[bits];
400                else
401                    *destbuf++ = bits;
402            }
403            pixels_read++;
404        } else {
405            bits = get_bits1(&gb);
406            if (bits == 1) {
407                run_length = get_bits(&gb, 3) + 3;
408                bits = get_bits(&gb, 2);
409
410                if (non_mod == 1 && bits == 1)
411                    pixels_read += run_length;
412                else {
413                    if (map_table)
414                        bits = map_table[bits];
415                    while (run_length-- > 0 && pixels_read < dbuf_len) {
416                        *destbuf++ = bits;
417                        pixels_read++;
418                    }
419                }
420            } else {
421                bits = get_bits1(&gb);
422                if (bits == 0) {
423                    bits = get_bits(&gb, 2);
424                    if (bits == 2) {
425                        run_length = get_bits(&gb, 4) + 12;
426                        bits = get_bits(&gb, 2);
427
428                        if (non_mod == 1 && bits == 1)
429                            pixels_read += run_length;
430                        else {
431                            if (map_table)
432                                bits = map_table[bits];
433                            while (run_length-- > 0 && pixels_read < dbuf_len) {
434                                *destbuf++ = bits;
435                                pixels_read++;
436                            }
437                        }
438                    } else if (bits == 3) {
439                        run_length = get_bits(&gb, 8) + 29;
440                        bits = get_bits(&gb, 2);
441
442                        if (non_mod == 1 && bits == 1)
443                            pixels_read += run_length;
444                        else {
445                            if (map_table)
446                                bits = map_table[bits];
447                            while (run_length-- > 0 && pixels_read < dbuf_len) {
448                                *destbuf++ = bits;
449                                pixels_read++;
450                            }
451                        }
452                    } else if (bits == 1) {
453                        if (map_table)
454                            bits = map_table[0];
455                        else
456                            bits = 0;
457                        run_length = 2;
458                        while (run_length-- > 0 && pixels_read < dbuf_len) {
459                            *destbuf++ = bits;
460                            pixels_read++;
461                        }
462                    } else {
463                        (*srcbuf) += (get_bits_count(&gb) + 7) >> 3;
464                        return pixels_read;
465                    }
466                } else {
467                    if (map_table)
468                        bits = map_table[0];
469                    else
470                        bits = 0;
471                    *destbuf++ = bits;
472                    pixels_read++;
473                }
474            }
475        }
476    }
477
478    if (get_bits(&gb, 6))
479        av_log(avctx, AV_LOG_ERROR, "line overflow\n");
480
481    (*srcbuf) += (get_bits_count(&gb) + 7) >> 3;
482
483    return pixels_read;
484}
485
486static int dvbsub_read_4bit_string(AVCodecContext *avctx, uint8_t *destbuf, int dbuf_len,
487                                   const uint8_t **srcbuf, int buf_size,
488                                   int non_mod, uint8_t *map_table, int x_pos)
489{
490    GetBitContext gb;
491
492    int bits;
493    int run_length;
494    int pixels_read = x_pos;
495
496    init_get_bits(&gb, *srcbuf, buf_size << 3);
497
498    destbuf += x_pos;
499
500    while (get_bits_count(&gb) < buf_size << 3 && pixels_read < dbuf_len) {
501        bits = get_bits(&gb, 4);
502
503        if (bits) {
504            if (non_mod != 1 || bits != 1) {
505                if (map_table)
506                    *destbuf++ = map_table[bits];
507                else
508                    *destbuf++ = bits;
509            }
510            pixels_read++;
511        } else {
512            bits = get_bits1(&gb);
513            if (bits == 0) {
514                run_length = get_bits(&gb, 3);
515
516                if (run_length == 0) {
517                    (*srcbuf) += (get_bits_count(&gb) + 7) >> 3;
518                    return pixels_read;
519                }
520
521                run_length += 2;
522
523                if (map_table)
524                    bits = map_table[0];
525                else
526                    bits = 0;
527
528                while (run_length-- > 0 && pixels_read < dbuf_len) {
529                    *destbuf++ = bits;
530                    pixels_read++;
531                }
532            } else {
533                bits = get_bits1(&gb);
534                if (bits == 0) {
535                    run_length = get_bits(&gb, 2) + 4;
536                    bits = get_bits(&gb, 4);
537
538                    if (non_mod == 1 && bits == 1)
539                        pixels_read += run_length;
540                    else {
541                        if (map_table)
542                            bits = map_table[bits];
543                        while (run_length-- > 0 && pixels_read < dbuf_len) {
544                            *destbuf++ = bits;
545                            pixels_read++;
546                        }
547                    }
548                } else {
549                    bits = get_bits(&gb, 2);
550                    if (bits == 2) {
551                        run_length = get_bits(&gb, 4) + 9;
552                        bits = get_bits(&gb, 4);
553
554                        if (non_mod == 1 && bits == 1)
555                            pixels_read += run_length;
556                        else {
557                            if (map_table)
558                                bits = map_table[bits];
559                            while (run_length-- > 0 && pixels_read < dbuf_len) {
560                                *destbuf++ = bits;
561                                pixels_read++;
562                            }
563                        }
564                    } else if (bits == 3) {
565                        run_length = get_bits(&gb, 8) + 25;
566                        bits = get_bits(&gb, 4);
567
568                        if (non_mod == 1 && bits == 1)
569                            pixels_read += run_length;
570                        else {
571                            if (map_table)
572                                bits = map_table[bits];
573                            while (run_length-- > 0 && pixels_read < dbuf_len) {
574                                *destbuf++ = bits;
575                                pixels_read++;
576                            }
577                        }
578                    } else if (bits == 1) {
579                        if (map_table)
580                            bits = map_table[0];
581                        else
582                            bits = 0;
583                        run_length = 2;
584                        while (run_length-- > 0 && pixels_read < dbuf_len) {
585                            *destbuf++ = bits;
586                            pixels_read++;
587                        }
588                    } else {
589                        if (map_table)
590                            bits = map_table[0];
591                        else
592                            bits = 0;
593                        *destbuf++ = bits;
594                        pixels_read ++;
595                    }
596                }
597            }
598        }
599    }
600
601    if (get_bits(&gb, 8))
602        av_log(avctx, AV_LOG_ERROR, "line overflow\n");
603
604    (*srcbuf) += (get_bits_count(&gb) + 7) >> 3;
605
606    return pixels_read;
607}
608
609static int dvbsub_read_8bit_string(AVCodecContext *avctx,
610                                   uint8_t *destbuf, int dbuf_len,
611                                    const uint8_t **srcbuf, int buf_size,
612                                    int non_mod, uint8_t *map_table, int x_pos)
613{
614    const uint8_t *sbuf_end = (*srcbuf) + buf_size;
615    int bits;
616    int run_length;
617    int pixels_read = x_pos;
618
619    destbuf += x_pos;
620
621    while (*srcbuf < sbuf_end && pixels_read < dbuf_len) {
622        bits = *(*srcbuf)++;
623
624        if (bits) {
625            if (non_mod != 1 || bits != 1) {
626                if (map_table)
627                    *destbuf++ = map_table[bits];
628                else
629                    *destbuf++ = bits;
630            }
631            pixels_read++;
632        } else {
633            bits = *(*srcbuf)++;
634            run_length = bits & 0x7f;
635            if ((bits & 0x80) == 0) {
636                if (run_length == 0) {
637                    return pixels_read;
638                }
639
640                bits = 0;
641            } else {
642                bits = *(*srcbuf)++;
643            }
644            if (non_mod == 1 && bits == 1)
645                pixels_read += run_length;
646            else {
647                if (map_table)
648                    bits = map_table[bits];
649                while (run_length-- > 0 && pixels_read < dbuf_len) {
650                    *destbuf++ = bits;
651                    pixels_read++;
652                }
653            }
654        }
655    }
656
657    if (*(*srcbuf)++)
658        av_log(avctx, AV_LOG_ERROR, "line overflow\n");
659
660    return pixels_read;
661}
662
663static void compute_default_clut(DVBSubContext *ctx, uint8_t *clut, AVSubtitleRect *rect, int w, int h)
664{
665    uint8_t list[256] = {0};
666    uint8_t list_inv[256];
667    int counttab[256] = {0};
668    int (*counttab2)[256] = ctx->clut_count2;
669    int count, i, x, y;
670    ptrdiff_t stride = rect->linesize[0];
671
672    memset(ctx->clut_count2, 0 , sizeof(ctx->clut_count2));
673
674#define V(x,y) rect->data[0][(x) + (y)*stride]
675    for (y = 0; y<h; y++) {
676        for (x = 0; x<w; x++) {
677            int v = V(x,y) + 1;
678            int vl = x     ? V(x-1,y) + 1 : 0;
679            int vr = x+1<w ? V(x+1,y) + 1 : 0;
680            int vt = y     ? V(x,y-1) + 1 : 0;
681            int vb = y+1<h ? V(x,y+1) + 1 : 0;
682            counttab[v-1] += !!((v!=vl) + (v!=vr) + (v!=vt) + (v!=vb));
683            counttab2[vl][v-1] ++;
684            counttab2[vr][v-1] ++;
685            counttab2[vt][v-1] ++;
686            counttab2[vb][v-1] ++;
687        }
688    }
689#define L(x,y) list[d[(x) + (y)*stride]]
690
691    for (i = 0; i<256; i++) {
692        counttab2[i+1][i] = 0;
693    }
694    for (i = 0; i<256; i++) {
695        int bestscore = 0;
696        int bestv = 0;
697
698        for (x = 0; x < 256; x++) {
699            int scorev = 0;
700            if (list[x])
701                continue;
702            scorev += counttab2[0][x];
703            for (y = 0; y < 256; y++) {
704                scorev += list[y] * counttab2[y+1][x];
705            }
706
707            if (scorev) {
708                int score = 1024LL*scorev / counttab[x];
709                if (score > bestscore) {
710                    bestscore = score;
711                    bestv = x;
712                }
713            }
714        }
715        if (!bestscore)
716            break;
717        list    [ bestv ] = 1;
718        list_inv[     i ] = bestv;
719    }
720
721    count = FFMAX(i - 1, 1);
722    for (i--; i >= 0; i--) {
723        int v = i * 255 / count;
724        AV_WN32(clut + 4*list_inv[i], RGBA(v/2,v,v/2,v));
725    }
726}
727
728
729static int save_subtitle_set(AVCodecContext *avctx, AVSubtitle *sub, int *got_output)
730{
731    DVBSubContext *ctx = avctx->priv_data;
732    DVBSubRegionDisplay *display;
733    DVBSubDisplayDefinition *display_def = ctx->display_definition;
734    DVBSubRegion *region;
735    AVSubtitleRect *rect;
736    const DVBSubCLUT *clut;
737    const uint32_t *clut_table;
738    int i;
739    int offset_x=0, offset_y=0;
740    int ret = 0;
741
742
743    if (display_def) {
744        offset_x = display_def->x;
745        offset_y = display_def->y;
746    }
747
748    /* Not touching AVSubtitles again*/
749    if (sub->num_rects) {
750        avpriv_request_sample(ctx, "Different Version of Segment asked Twice");
751        return AVERROR_PATCHWELCOME;
752    }
753    for (display = ctx->display_list; display; display = display->next) {
754        region = get_region(ctx, display->region_id);
755        if (region && region->dirty)
756            sub->num_rects++;
757    }
758
759    if (ctx->compute_edt == 0) {
760        sub->end_display_time = ctx->time_out * 1000;
761        *got_output = 1;
762    } else if (ctx->prev_start != AV_NOPTS_VALUE) {
763        sub->end_display_time = av_rescale_q((sub->pts - ctx->prev_start ), AV_TIME_BASE_Q, (AVRational){ 1, 1000 }) - 1;
764        *got_output = 1;
765    }
766    if (sub->num_rects > 0) {
767
768        sub->rects = av_calloc(sub->num_rects, sizeof(*sub->rects));
769        if (!sub->rects) {
770            ret = AVERROR(ENOMEM);
771            goto fail;
772        }
773
774        for (i = 0; i < sub->num_rects; i++) {
775            sub->rects[i] = av_mallocz(sizeof(*sub->rects[i]));
776            if (!sub->rects[i]) {
777                ret = AVERROR(ENOMEM);
778                goto fail;
779            }
780        }
781
782        i = 0;
783
784        for (display = ctx->display_list; display; display = display->next) {
785            region = get_region(ctx, display->region_id);
786
787            if (!region)
788                continue;
789
790            if (!region->dirty)
791                continue;
792
793            rect = sub->rects[i];
794            rect->x = display->x_pos + offset_x;
795            rect->y = display->y_pos + offset_y;
796            rect->w = region->width;
797            rect->h = region->height;
798            rect->nb_colors = (1 << region->depth);
799            rect->type      = SUBTITLE_BITMAP;
800            rect->linesize[0] = region->width;
801
802            clut = get_clut(ctx, region->clut);
803
804            if (!clut)
805                clut = &default_clut;
806
807            switch (region->depth) {
808            case 2:
809                clut_table = clut->clut4;
810                break;
811            case 8:
812                clut_table = clut->clut256;
813                break;
814            case 4:
815            default:
816                clut_table = clut->clut16;
817                break;
818            }
819
820            rect->data[1] = av_mallocz(AVPALETTE_SIZE);
821            if (!rect->data[1]) {
822                ret = AVERROR(ENOMEM);
823                goto fail;
824            }
825            memcpy(rect->data[1], clut_table, (1 << region->depth) * sizeof(*clut_table));
826
827            rect->data[0] = av_memdup(region->pbuf, region->buf_size);
828            if (!rect->data[0]) {
829                ret = AVERROR(ENOMEM);
830                goto fail;
831            }
832
833            if ((clut == &default_clut && ctx->compute_clut < 0) || ctx->compute_clut == 1) {
834                if (!region->has_computed_clut) {
835                    compute_default_clut(ctx, region->computed_clut, rect, rect->w, rect->h);
836                    region->has_computed_clut = 1;
837                }
838
839                memcpy(rect->data[1], region->computed_clut, sizeof(region->computed_clut));
840            }
841
842            i++;
843        }
844    }
845
846    return 0;
847fail:
848    if (sub->rects) {
849        for (i=0; i < sub->num_rects; i++) {
850            rect = sub->rects[i];
851            if (rect) {
852                av_freep(&rect->data[0]);
853                av_freep(&rect->data[1]);
854            }
855            av_freep(&sub->rects[i]);
856        }
857        av_freep(&sub->rects);
858    }
859    sub->num_rects = 0;
860    return ret;
861}
862
863static void dvbsub_parse_pixel_data_block(AVCodecContext *avctx, DVBSubObjectDisplay *display,
864                                          const uint8_t *buf, int buf_size, int top_bottom, int non_mod)
865{
866    DVBSubContext *ctx = avctx->priv_data;
867
868    DVBSubRegion *region = get_region(ctx, display->region_id);
869    const uint8_t *buf_end = buf + buf_size;
870    uint8_t *pbuf;
871    int x_pos, y_pos;
872    int i;
873
874    uint8_t map2to4[] = { 0x0,  0x7,  0x8,  0xf};
875    uint8_t map2to8[] = {0x00, 0x77, 0x88, 0xff};
876    uint8_t map4to8[] = {0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,
877                         0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff};
878    uint8_t *map_table;
879
880#if 0
881    ff_dlog(avctx, "DVB pixel block size %d, %s field:\n", buf_size,
882            top_bottom ? "bottom" : "top");
883
884    for (i = 0; i < buf_size; i++) {
885        if (i % 16 == 0)
886            ff_dlog(avctx, "0x%8p: ", buf+i);
887
888        ff_dlog(avctx, "%02x ", buf[i]);
889        if (i % 16 == 15)
890            ff_dlog(avctx, "\n");
891    }
892
893    if (i % 16)
894        ff_dlog(avctx, "\n");
895#endif
896
897    if (!region)
898        return;
899
900    pbuf = region->pbuf;
901    region->dirty = 1;
902
903    x_pos = display->x_pos;
904    y_pos = display->y_pos;
905
906    y_pos += top_bottom;
907
908    while (buf < buf_end) {
909        if ((*buf!=0xf0 && x_pos >= region->width) || y_pos >= region->height) {
910            av_log(avctx, AV_LOG_ERROR, "Invalid object location! %d-%d %d-%d %02x\n", x_pos, region->width, y_pos, region->height, *buf);
911            return;
912        }
913
914        switch (*buf++) {
915        case 0x10:
916            if (region->depth == 8)
917                map_table = map2to8;
918            else if (region->depth == 4)
919                map_table = map2to4;
920            else
921                map_table = NULL;
922
923            x_pos = dvbsub_read_2bit_string(avctx, pbuf + (y_pos * region->width),
924                                            region->width, &buf, buf_end - buf,
925                                            non_mod, map_table, x_pos);
926            break;
927        case 0x11:
928            if (region->depth < 4) {
929                av_log(avctx, AV_LOG_ERROR, "4-bit pixel string in %d-bit region!\n", region->depth);
930                return;
931            }
932
933            if (region->depth == 8)
934                map_table = map4to8;
935            else
936                map_table = NULL;
937
938            x_pos = dvbsub_read_4bit_string(avctx, pbuf + (y_pos * region->width),
939                                            region->width, &buf, buf_end - buf,
940                                            non_mod, map_table, x_pos);
941            break;
942        case 0x12:
943            if (region->depth < 8) {
944                av_log(avctx, AV_LOG_ERROR, "8-bit pixel string in %d-bit region!\n", region->depth);
945                return;
946            }
947
948            x_pos = dvbsub_read_8bit_string(avctx, pbuf + (y_pos * region->width),
949                                            region->width, &buf, buf_end - buf,
950                                            non_mod, NULL, x_pos);
951            break;
952
953        case 0x20:
954            map2to4[0] = (*buf) >> 4;
955            map2to4[1] = (*buf++) & 0xf;
956            map2to4[2] = (*buf) >> 4;
957            map2to4[3] = (*buf++) & 0xf;
958            break;
959        case 0x21:
960            for (i = 0; i < 4; i++)
961                map2to8[i] = *buf++;
962            break;
963        case 0x22:
964            for (i = 0; i < 16; i++)
965                map4to8[i] = *buf++;
966            break;
967
968        case 0xf0:
969            x_pos = display->x_pos;
970            y_pos += 2;
971            break;
972        default:
973            av_log(avctx, AV_LOG_INFO, "Unknown/unsupported pixel block 0x%x\n", *(buf-1));
974        }
975    }
976
977    if (ctx->compute_clut != -2)
978        region->has_computed_clut = 0;
979}
980
981static int dvbsub_parse_object_segment(AVCodecContext *avctx,
982                                       const uint8_t *buf, int buf_size)
983{
984    DVBSubContext *ctx = avctx->priv_data;
985
986    const uint8_t *buf_end = buf + buf_size;
987    int object_id;
988    DVBSubObject *object;
989    DVBSubObjectDisplay *display;
990    int top_field_len, bottom_field_len;
991
992    int coding_method, non_modifying_color;
993
994    object_id = AV_RB16(buf);
995    buf += 2;
996
997    object = get_object(ctx, object_id);
998
999    if (!object)
1000        return AVERROR_INVALIDDATA;
1001
1002    coding_method = ((*buf) >> 2) & 3;
1003    non_modifying_color = ((*buf++) >> 1) & 1;
1004
1005    if (coding_method == 0) {
1006        top_field_len = AV_RB16(buf);
1007        buf += 2;
1008        bottom_field_len = AV_RB16(buf);
1009        buf += 2;
1010
1011        if (buf + top_field_len + bottom_field_len > buf_end) {
1012            av_log(avctx, AV_LOG_ERROR, "Field data size %d+%d too large\n", top_field_len, bottom_field_len);
1013            return AVERROR_INVALIDDATA;
1014        }
1015
1016        for (display = object->display_list; display; display = display->object_list_next) {
1017            const uint8_t *block = buf;
1018            int bfl = bottom_field_len;
1019
1020            dvbsub_parse_pixel_data_block(avctx, display, block, top_field_len, 0,
1021                                            non_modifying_color);
1022
1023            if (bottom_field_len > 0)
1024                block = buf + top_field_len;
1025            else
1026                bfl = top_field_len;
1027
1028            dvbsub_parse_pixel_data_block(avctx, display, block, bfl, 1,
1029                                            non_modifying_color);
1030        }
1031    } else if (coding_method == 1) {
1032        avpriv_report_missing_feature(avctx, "coded as a string of characters");
1033        return AVERROR_PATCHWELCOME;
1034    } else if (coding_method == 2) {
1035        avpriv_report_missing_feature(avctx, "progressive coding of pixels");
1036        return AVERROR_PATCHWELCOME;
1037    } else {
1038        av_log(avctx, AV_LOG_ERROR, "Unknown object coding %d\n", coding_method);
1039        return AVERROR_INVALIDDATA;
1040    }
1041
1042    return 0;
1043}
1044
1045static int dvbsub_parse_clut_segment(AVCodecContext *avctx,
1046                                     const uint8_t *buf, int buf_size)
1047{
1048    DVBSubContext *ctx = avctx->priv_data;
1049
1050    const uint8_t *buf_end = buf + buf_size;
1051    int i, clut_id;
1052    int version;
1053    DVBSubCLUT *clut;
1054    int entry_id, depth , full_range;
1055    int y, cr, cb, alpha;
1056    int r, g, b, r_add, g_add, b_add;
1057
1058    ff_dlog(avctx, "DVB clut packet:\n");
1059
1060    for (i=0; i < buf_size; i++) {
1061        ff_dlog(avctx, "%02x ", buf[i]);
1062        if (i % 16 == 15)
1063            ff_dlog(avctx, "\n");
1064    }
1065
1066    if (i % 16)
1067        ff_dlog(avctx, "\n");
1068
1069    clut_id = *buf++;
1070    version = ((*buf)>>4)&15;
1071    buf += 1;
1072
1073    clut = get_clut(ctx, clut_id);
1074
1075    if (!clut) {
1076        clut = av_memdup(&default_clut, sizeof(*clut));
1077        if (!clut)
1078            return AVERROR(ENOMEM);
1079
1080        clut->id = clut_id;
1081        clut->version = -1;
1082
1083        clut->next = ctx->clut_list;
1084        ctx->clut_list = clut;
1085    }
1086
1087    if (clut->version != version) {
1088
1089        clut->version = version;
1090
1091        while (buf + 4 < buf_end) {
1092            entry_id = *buf++;
1093
1094            depth = (*buf) & 0xe0;
1095
1096            if (depth == 0) {
1097                av_log(avctx, AV_LOG_ERROR, "Invalid clut depth 0x%x!\n", *buf);
1098            }
1099
1100            full_range = (*buf++) & 1;
1101
1102            if (full_range) {
1103                y     = *buf++;
1104                cr    = *buf++;
1105                cb    = *buf++;
1106                alpha = *buf++;
1107            } else {
1108                y     = buf[0] & 0xfc;
1109                cr    = (((buf[0] & 3) << 2) | ((buf[1] >> 6) & 3)) << 4;
1110                cb    = (buf[1] << 2) & 0xf0;
1111                alpha = (buf[1] << 6) & 0xc0;
1112
1113                buf += 2;
1114            }
1115
1116            if (y == 0)
1117                alpha = 0xff;
1118
1119            YUV_TO_RGB1_CCIR(cb, cr);
1120            YUV_TO_RGB2_CCIR(r, g, b, y);
1121
1122            ff_dlog(avctx, "clut %d := (%d,%d,%d,%d)\n", entry_id, r, g, b, alpha);
1123            if (!!(depth & 0x80) + !!(depth & 0x40) + !!(depth & 0x20) > 1) {
1124                ff_dlog(avctx, "More than one bit level marked: %x\n", depth);
1125                if (avctx->strict_std_compliance > FF_COMPLIANCE_NORMAL)
1126                    return AVERROR_INVALIDDATA;
1127            }
1128
1129            if (depth & 0x80 && entry_id < 4)
1130                clut->clut4[entry_id] = RGBA(r,g,b,255 - alpha);
1131            else if (depth & 0x40 && entry_id < 16)
1132                clut->clut16[entry_id] = RGBA(r,g,b,255 - alpha);
1133            else if (depth & 0x20)
1134                clut->clut256[entry_id] = RGBA(r,g,b,255 - alpha);
1135        }
1136    }
1137
1138    return 0;
1139}
1140
1141
1142static int dvbsub_parse_region_segment(AVCodecContext *avctx,
1143                                       const uint8_t *buf, int buf_size)
1144{
1145    DVBSubContext *ctx = avctx->priv_data;
1146
1147    const uint8_t *buf_end = buf + buf_size;
1148    int region_id, object_id;
1149    int av_unused version;
1150    DVBSubRegion *region;
1151    DVBSubObject *object;
1152    DVBSubObjectDisplay *display;
1153    int fill;
1154    int ret;
1155
1156    if (buf_size < 10)
1157        return AVERROR_INVALIDDATA;
1158
1159    region_id = *buf++;
1160
1161    region = get_region(ctx, region_id);
1162
1163    if (!region) {
1164        region = av_mallocz(sizeof(*region));
1165        if (!region)
1166            return AVERROR(ENOMEM);
1167
1168        region->id = region_id;
1169        region->version = -1;
1170
1171        region->next = ctx->region_list;
1172        ctx->region_list = region;
1173    }
1174
1175    version = ((*buf)>>4) & 15;
1176    fill = ((*buf++) >> 3) & 1;
1177
1178    region->width = AV_RB16(buf);
1179    buf += 2;
1180    region->height = AV_RB16(buf);
1181    buf += 2;
1182
1183    ret = av_image_check_size2(region->width, region->height, avctx->max_pixels, AV_PIX_FMT_PAL8, 0, avctx);
1184    if (ret >= 0 && region->width * region->height * 2 > 320 * 1024 * 8) {
1185        ret = AVERROR_INVALIDDATA;
1186        av_log(avctx, AV_LOG_ERROR, "Pixel buffer memory constraint violated\n");
1187    }
1188    if (ret < 0) {
1189        region->width= region->height= 0;
1190        return ret;
1191    }
1192
1193    if (region->width * region->height != region->buf_size) {
1194        av_free(region->pbuf);
1195
1196        region->buf_size = region->width * region->height;
1197
1198        region->pbuf = av_malloc(region->buf_size);
1199        if (!region->pbuf) {
1200            region->buf_size =
1201            region->width =
1202            region->height = 0;
1203            return AVERROR(ENOMEM);
1204        }
1205
1206        fill = 1;
1207        region->dirty = 0;
1208    }
1209
1210    region->depth = 1 << (((*buf++) >> 2) & 7);
1211    if (region->depth < 2 || region->depth > 8) {
1212        av_log(avctx, AV_LOG_ERROR, "region depth %d is invalid\n", region->depth);
1213        region->depth= 4;
1214    }
1215    region->clut = *buf++;
1216
1217    if (region->depth == 8) {
1218        region->bgcolor = *buf++;
1219        buf += 1;
1220    } else {
1221        buf += 1;
1222
1223        if (region->depth == 4)
1224            region->bgcolor = (((*buf++) >> 4) & 15);
1225        else
1226            region->bgcolor = (((*buf++) >> 2) & 3);
1227    }
1228
1229    ff_dlog(avctx, "Region %d, (%dx%d)\n", region_id, region->width, region->height);
1230
1231    if (fill) {
1232        memset(region->pbuf, region->bgcolor, region->buf_size);
1233        ff_dlog(avctx, "Fill region (%d)\n", region->bgcolor);
1234    }
1235
1236    delete_region_display_list(ctx, region);
1237
1238    while (buf + 5 < buf_end) {
1239        object_id = AV_RB16(buf);
1240        buf += 2;
1241
1242        object = get_object(ctx, object_id);
1243
1244        if (!object) {
1245            object = av_mallocz(sizeof(*object));
1246            if (!object)
1247                return AVERROR(ENOMEM);
1248
1249            object->id = object_id;
1250            object->next = ctx->object_list;
1251            ctx->object_list = object;
1252        }
1253
1254        object->type = (*buf) >> 6;
1255
1256        display = av_mallocz(sizeof(*display));
1257        if (!display)
1258            return AVERROR(ENOMEM);
1259
1260        display->object_id = object_id;
1261        display->region_id = region_id;
1262
1263        display->x_pos = AV_RB16(buf) & 0xfff;
1264        buf += 2;
1265        display->y_pos = AV_RB16(buf) & 0xfff;
1266        buf += 2;
1267
1268        if (display->x_pos >= region->width ||
1269            display->y_pos >= region->height) {
1270            av_log(avctx, AV_LOG_ERROR, "Object outside region\n");
1271            av_free(display);
1272            return AVERROR_INVALIDDATA;
1273        }
1274
1275        if ((object->type == 1 || object->type == 2) && buf+1 < buf_end) {
1276            display->fgcolor = *buf++;
1277            display->bgcolor = *buf++;
1278        }
1279
1280        display->region_list_next = region->display_list;
1281        region->display_list = display;
1282
1283        display->object_list_next = object->display_list;
1284        object->display_list = display;
1285    }
1286
1287    return 0;
1288}
1289
1290static int dvbsub_parse_page_segment(AVCodecContext *avctx,
1291                                     const uint8_t *buf, int buf_size, AVSubtitle *sub, int *got_output)
1292{
1293    DVBSubContext *ctx = avctx->priv_data;
1294    DVBSubRegionDisplay *display;
1295    DVBSubRegionDisplay *tmp_display_list, **tmp_ptr;
1296
1297    const uint8_t *buf_end = buf + buf_size;
1298    int region_id;
1299    int page_state;
1300    int timeout;
1301    int version;
1302
1303    if (buf_size < 1)
1304        return AVERROR_INVALIDDATA;
1305
1306    timeout = *buf++;
1307    version = ((*buf)>>4) & 15;
1308    page_state = ((*buf++) >> 2) & 3;
1309
1310    if (ctx->version == version) {
1311        return 0;
1312    }
1313
1314    ctx->time_out = timeout;
1315    ctx->version = version;
1316
1317    ff_dlog(avctx, "Page time out %ds, state %d\n", ctx->time_out, page_state);
1318
1319    if (ctx->compute_edt == 1)
1320        save_subtitle_set(avctx, sub, got_output);
1321
1322    if (page_state == 1 || page_state == 2) {
1323        delete_regions(ctx);
1324        delete_objects(ctx);
1325        delete_cluts(ctx);
1326    }
1327
1328    tmp_display_list = ctx->display_list;
1329    ctx->display_list = NULL;
1330
1331    while (buf + 5 < buf_end) {
1332        region_id = *buf++;
1333        buf += 1;
1334
1335        display = ctx->display_list;
1336        while (display && display->region_id != region_id) {
1337            display = display->next;
1338        }
1339        if (display) {
1340            av_log(avctx, AV_LOG_ERROR, "duplicate region\n");
1341            break;
1342        }
1343
1344        display = tmp_display_list;
1345        tmp_ptr = &tmp_display_list;
1346
1347        while (display && display->region_id != region_id) {
1348            tmp_ptr = &display->next;
1349            display = display->next;
1350        }
1351
1352        if (!display) {
1353            display = av_mallocz(sizeof(*display));
1354            if (!display)
1355                return AVERROR(ENOMEM);
1356        }
1357
1358        display->region_id = region_id;
1359
1360        display->x_pos = AV_RB16(buf);
1361        buf += 2;
1362        display->y_pos = AV_RB16(buf);
1363        buf += 2;
1364
1365        *tmp_ptr = display->next;
1366
1367        display->next = ctx->display_list;
1368        ctx->display_list = display;
1369
1370        ff_dlog(avctx, "Region %d, (%d,%d)\n", region_id, display->x_pos, display->y_pos);
1371    }
1372
1373    while (tmp_display_list) {
1374        display = tmp_display_list;
1375
1376        tmp_display_list = display->next;
1377
1378        av_freep(&display);
1379    }
1380
1381    return 0;
1382}
1383
1384static int dvbsub_parse_display_definition_segment(AVCodecContext *avctx,
1385                                                   const uint8_t *buf,
1386                                                   int buf_size)
1387{
1388    DVBSubContext *ctx = avctx->priv_data;
1389    DVBSubDisplayDefinition *display_def = ctx->display_definition;
1390    int dds_version, info_byte;
1391
1392    if (buf_size < 5)
1393        return AVERROR_INVALIDDATA;
1394
1395    info_byte   = bytestream_get_byte(&buf);
1396    dds_version = info_byte >> 4;
1397    if (display_def && display_def->version == dds_version)
1398        return 0; // already have this display definition version
1399
1400    if (!display_def) {
1401        display_def             = av_mallocz(sizeof(*display_def));
1402        if (!display_def)
1403            return AVERROR(ENOMEM);
1404        ctx->display_definition = display_def;
1405    }
1406
1407    display_def->version = dds_version;
1408    display_def->x       = 0;
1409    display_def->y       = 0;
1410    display_def->width   = bytestream_get_be16(&buf) + 1;
1411    display_def->height  = bytestream_get_be16(&buf) + 1;
1412    if (!avctx->width || !avctx->height) {
1413        int ret = ff_set_dimensions(avctx, display_def->width, display_def->height);
1414        if (ret < 0)
1415            return ret;
1416    }
1417
1418    if (info_byte & 1<<3) { // display_window_flag
1419        if (buf_size < 13)
1420            return AVERROR_INVALIDDATA;
1421
1422        display_def->x = bytestream_get_be16(&buf);
1423        display_def->width  = bytestream_get_be16(&buf) - display_def->x + 1;
1424        display_def->y = bytestream_get_be16(&buf);
1425        display_def->height = bytestream_get_be16(&buf) - display_def->y + 1;
1426    }
1427
1428    return 0;
1429}
1430
1431static int dvbsub_display_end_segment(AVCodecContext *avctx, const uint8_t *buf,
1432                                      int buf_size, AVSubtitle *sub,int *got_output)
1433{
1434    DVBSubContext *ctx = avctx->priv_data;
1435
1436    if (ctx->compute_edt == 0)
1437        save_subtitle_set(avctx, sub, got_output);
1438    return 0;
1439}
1440
1441static int dvbsub_decode(AVCodecContext *avctx, AVSubtitle *sub,
1442                         int *got_sub_ptr, const AVPacket *avpkt)
1443{
1444    const uint8_t *buf = avpkt->data;
1445    int buf_size = avpkt->size;
1446    DVBSubContext *ctx = avctx->priv_data;
1447    const uint8_t *p, *p_end;
1448    int segment_type;
1449    int page_id;
1450    int segment_length;
1451    int i;
1452    int ret = 0;
1453    int got_segment = 0;
1454    int got_dds = 0;
1455
1456    ff_dlog(avctx, "DVB sub packet:\n");
1457
1458    for (i=0; i < buf_size; i++) {
1459        ff_dlog(avctx, "%02x ", buf[i]);
1460        if (i % 16 == 15)
1461            ff_dlog(avctx, "\n");
1462    }
1463
1464    if (i % 16)
1465        ff_dlog(avctx, "\n");
1466
1467    if (buf_size <= 6 || *buf != 0x0f) {
1468        ff_dlog(avctx, "incomplete or broken packet");
1469        return AVERROR_INVALIDDATA;
1470    }
1471
1472    p = buf;
1473    p_end = buf + buf_size;
1474
1475    while (p_end - p >= 6 && *p == 0x0f) {
1476        p += 1;
1477        segment_type = *p++;
1478        page_id = AV_RB16(p);
1479        p += 2;
1480        segment_length = AV_RB16(p);
1481        p += 2;
1482
1483        if (avctx->debug & FF_DEBUG_STARTCODE) {
1484            av_log(avctx, AV_LOG_DEBUG, "segment_type:%d page_id:%d segment_length:%d\n", segment_type, page_id, segment_length);
1485        }
1486
1487        if (p_end - p < segment_length) {
1488            ff_dlog(avctx, "incomplete or broken packet");
1489            ret = -1;
1490            goto end;
1491        }
1492
1493        if (page_id == ctx->composition_id || page_id == ctx->ancillary_id ||
1494            ctx->composition_id == -1 || ctx->ancillary_id == -1) {
1495            int ret = 0;
1496            switch (segment_type) {
1497            case DVBSUB_PAGE_SEGMENT:
1498                ret = dvbsub_parse_page_segment(avctx, p, segment_length, sub, got_sub_ptr);
1499                got_segment |= 1;
1500                break;
1501            case DVBSUB_REGION_SEGMENT:
1502                ret = dvbsub_parse_region_segment(avctx, p, segment_length);
1503                got_segment |= 2;
1504                break;
1505            case DVBSUB_CLUT_SEGMENT:
1506                ret = dvbsub_parse_clut_segment(avctx, p, segment_length);
1507                if (ret < 0) goto end;
1508                got_segment |= 4;
1509                break;
1510            case DVBSUB_OBJECT_SEGMENT:
1511                ret = dvbsub_parse_object_segment(avctx, p, segment_length);
1512                got_segment |= 8;
1513                break;
1514            case DVBSUB_DISPLAYDEFINITION_SEGMENT:
1515                ret = dvbsub_parse_display_definition_segment(avctx, p,
1516                                                              segment_length);
1517                got_dds = 1;
1518                break;
1519            case DVBSUB_DISPLAY_SEGMENT:
1520                ret = dvbsub_display_end_segment(avctx, p, segment_length, sub, got_sub_ptr);
1521                if (got_segment == 15 && !got_dds && !avctx->width && !avctx->height) {
1522                    // Default from ETSI EN 300 743 V1.3.1 (7.2.1)
1523                    avctx->width  = 720;
1524                    avctx->height = 576;
1525                }
1526                got_segment |= 16;
1527                break;
1528            default:
1529                ff_dlog(avctx, "Subtitling segment type 0x%x, page id %d, length %d\n",
1530                        segment_type, page_id, segment_length);
1531                break;
1532            }
1533            if (ret < 0)
1534                goto end;
1535        }
1536
1537        p += segment_length;
1538    }
1539    // Some streams do not send a display segment but if we have all the other
1540    // segments then we need no further data.
1541    if (got_segment == 15) {
1542        av_log(avctx, AV_LOG_DEBUG, "Missing display_end_segment, emulating\n");
1543        dvbsub_display_end_segment(avctx, p, 0, sub, got_sub_ptr);
1544    }
1545
1546end:
1547    if (ret < 0) {
1548        return ret;
1549    } else {
1550        if (ctx->compute_edt == 1)
1551            FFSWAP(int64_t, ctx->prev_start, sub->pts);
1552    }
1553
1554    return p - buf;
1555}
1556
1557#define DS AV_OPT_FLAG_DECODING_PARAM | AV_OPT_FLAG_SUBTITLE_PARAM
1558#define OFFSET(x) offsetof(DVBSubContext, x)
1559static const AVOption options[] = {
1560    {"compute_edt", "compute end of time using pts or timeout", OFFSET(compute_edt), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, DS},
1561    {"compute_clut", "compute clut when not available(-1) or only once (-2) or always(1) or never(0)", OFFSET(compute_clut), AV_OPT_TYPE_BOOL, {.i64 = -1}, -2, 1, DS},
1562    {"dvb_substream", "", OFFSET(substream), AV_OPT_TYPE_INT, {.i64 = -1}, -1, 63, DS},
1563    {NULL}
1564};
1565static const AVClass dvbsubdec_class = {
1566    .class_name = "DVB Sub Decoder",
1567    .item_name  = av_default_item_name,
1568    .option     = options,
1569    .version    = LIBAVUTIL_VERSION_INT,
1570};
1571
1572const FFCodec ff_dvbsub_decoder = {
1573    .p.name         = "dvbsub",
1574    .p.long_name    = NULL_IF_CONFIG_SMALL("DVB subtitles"),
1575    .p.type         = AVMEDIA_TYPE_SUBTITLE,
1576    .p.id           = AV_CODEC_ID_DVB_SUBTITLE,
1577    .priv_data_size = sizeof(DVBSubContext),
1578    .init           = dvbsub_init_decoder,
1579    .close          = dvbsub_close_decoder,
1580    FF_CODEC_DECODE_SUB_CB(dvbsub_decode),
1581    .p.priv_class   = &dvbsubdec_class,
1582    .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
1583};
1584