1/*
2 * DVB subtitle encoding
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 "bytestream.h"
23#include "libavutil/colorspace.h"
24
25typedef struct DVBSubtitleContext {
26    int object_version;
27} DVBSubtitleContext;
28
29#define PUTBITS2(val)\
30{\
31    bitbuf |= (val) << bitcnt;\
32    bitcnt -= 2;\
33    if (bitcnt < 0) {\
34        bitcnt = 6;\
35        *q++ = bitbuf;\
36        bitbuf = 0;\
37    }\
38}
39
40static void dvb_encode_rle2(uint8_t **pq,
41                            const uint8_t *bitmap, int linesize,
42                            int w, int h)
43{
44    uint8_t *q;
45    unsigned int bitbuf;
46    int bitcnt;
47    int x, y, len, x1, v, color;
48
49    q = *pq;
50
51    for(y = 0; y < h; y++) {
52        *q++ = 0x10;
53        bitbuf = 0;
54        bitcnt = 6;
55
56        x = 0;
57        while (x < w) {
58            x1 = x;
59            color = bitmap[x1++];
60            while (x1 < w && bitmap[x1] == color)
61                x1++;
62            len = x1 - x;
63            if (color == 0 && len == 2) {
64                PUTBITS2(0);
65                PUTBITS2(0);
66                PUTBITS2(1);
67            } else if (len >= 3 && len <= 10) {
68                v = len - 3;
69                PUTBITS2(0);
70                PUTBITS2((v >> 2) | 2);
71                PUTBITS2(v & 3);
72                PUTBITS2(color);
73            } else if (len >= 12 && len <= 27) {
74                v = len - 12;
75                PUTBITS2(0);
76                PUTBITS2(0);
77                PUTBITS2(2);
78                PUTBITS2(v >> 2);
79                PUTBITS2(v & 3);
80                PUTBITS2(color);
81            } else if (len >= 29) {
82                /* length = 29 ... 284 */
83                if (len > 284)
84                    len = 284;
85                v = len - 29;
86                PUTBITS2(0);
87                PUTBITS2(0);
88                PUTBITS2(3);
89                PUTBITS2((v >> 6));
90                PUTBITS2((v >> 4) & 3);
91                PUTBITS2((v >> 2) & 3);
92                PUTBITS2(v & 3);
93                PUTBITS2(color);
94            } else {
95                PUTBITS2(color);
96                if (color == 0) {
97                    PUTBITS2(1);
98                }
99                len = 1;
100            }
101            x += len;
102        }
103        /* end of line */
104        PUTBITS2(0);
105        PUTBITS2(0);
106        PUTBITS2(0);
107        if (bitcnt != 6) {
108            *q++ = bitbuf;
109        }
110        *q++ = 0xf0;
111        bitmap += linesize;
112    }
113    *pq = q;
114}
115
116#define PUTBITS4(val)\
117{\
118    bitbuf |= (val) << bitcnt;\
119    bitcnt -= 4;\
120    if (bitcnt < 0) {\
121        bitcnt = 4;\
122        *q++ = bitbuf;\
123        bitbuf = 0;\
124    }\
125}
126
127/* some DVB decoders only implement 4 bits/pixel */
128static void dvb_encode_rle4(uint8_t **pq,
129                            const uint8_t *bitmap, int linesize,
130                            int w, int h)
131{
132    uint8_t *q;
133    unsigned int bitbuf;
134    int bitcnt;
135    int x, y, len, x1, v, color;
136
137    q = *pq;
138
139    for(y = 0; y < h; y++) {
140        *q++ = 0x11;
141        bitbuf = 0;
142        bitcnt = 4;
143
144        x = 0;
145        while (x < w) {
146            x1 = x;
147            color = bitmap[x1++];
148            while (x1 < w && bitmap[x1] == color)
149                x1++;
150            len = x1 - x;
151            if (color == 0 && len == 2) {
152                PUTBITS4(0);
153                PUTBITS4(0xd);
154            } else if (color == 0 && (len >= 3 && len <= 9)) {
155                PUTBITS4(0);
156                PUTBITS4(len - 2);
157            } else if (len >= 4 && len <= 7) {
158                PUTBITS4(0);
159                PUTBITS4(8 + len - 4);
160                PUTBITS4(color);
161            } else if (len >= 9 && len <= 24) {
162                PUTBITS4(0);
163                PUTBITS4(0xe);
164                PUTBITS4(len - 9);
165                PUTBITS4(color);
166            } else if (len >= 25) {
167                if (len > 280)
168                    len = 280;
169                v = len - 25;
170                PUTBITS4(0);
171                PUTBITS4(0xf);
172                PUTBITS4(v >> 4);
173                PUTBITS4(v & 0xf);
174                PUTBITS4(color);
175            } else {
176                PUTBITS4(color);
177                if (color == 0) {
178                    PUTBITS4(0xc);
179                }
180                len = 1;
181            }
182            x += len;
183        }
184        /* end of line */
185        PUTBITS4(0);
186        PUTBITS4(0);
187        if (bitcnt != 4) {
188            *q++ = bitbuf;
189        }
190        *q++ = 0xf0;
191        bitmap += linesize;
192    }
193    *pq = q;
194}
195
196static void dvb_encode_rle8(uint8_t **pq,
197                            const uint8_t *bitmap, int linesize,
198                            int w, int h)
199{
200    uint8_t *q;
201    int x, y, len, x1, color;
202
203    q = *pq;
204
205    for (y = 0; y < h; y++) {
206        *q++ = 0x12;
207
208        x = 0;
209        while (x < w) {
210            x1 = x;
211            color = bitmap[x1++];
212            while (x1 < w && bitmap[x1] == color)
213                x1++;
214            len = x1 - x;
215            if (len == 1 && color) {
216                // 00000001 to 11111111           1 pixel in colour x
217                *q++ = color;
218            } else {
219                if (color == 0x00) {
220                    // 00000000 0LLLLLLL          L pixels (1-127) in colour 0 (L > 0)
221                    len = FFMIN(len, 127);
222                    *q++ = 0x00;
223                    *q++ = len;
224                } else if (len > 2) {
225                    // 00000000 1LLLLLLL CCCCCCCC L pixels (3-127) in colour C (L > 2)
226                    len = FFMIN(len, 127);
227                    *q++ = 0x00;
228                    *q++ = 0x80+len;
229                    *q++ = color;
230                }
231                else if (len == 2) {
232                    *q++ = color;
233                    *q++ = color;
234                } else {
235                    *q++ = color;
236                    len = 1;
237                }
238            }
239            x += len;
240        }
241        /* end of line */
242        // 00000000 00000000 end of 8-bit/pixel_code_string
243        *q++ = 0x00;
244        *q++ = 0x00;
245        bitmap += linesize;
246    }
247    *pq = q;
248}
249
250static int encode_dvb_subtitles(DVBSubtitleContext *s,
251                                uint8_t *outbuf, const AVSubtitle *h)
252{
253    uint8_t *q, *pseg_len;
254    int page_id, region_id, clut_id, object_id, i, bpp_index, page_state;
255
256
257    q = outbuf;
258
259    page_id = 1;
260
261    if (h->num_rects && h->rects == NULL)
262        return -1;
263
264    /* page composition segment */
265
266    *q++ = 0x0f; /* sync_byte */
267    *q++ = 0x10; /* segment_type */
268    bytestream_put_be16(&q, page_id);
269    pseg_len = q;
270    q += 2; /* segment length */
271    *q++ = 30; /* page_timeout (seconds) */
272    page_state = 2; /* mode change */
273    /* page_version = 0 + page_state */
274    *q++ = (s->object_version << 4) | (page_state << 2) | 3;
275
276    for (region_id = 0; region_id < h->num_rects; region_id++) {
277        *q++ = region_id;
278        *q++ = 0xff; /* reserved */
279        bytestream_put_be16(&q, h->rects[region_id]->x); /* left pos */
280        bytestream_put_be16(&q, h->rects[region_id]->y); /* top pos */
281    }
282
283    bytestream_put_be16(&pseg_len, q - pseg_len - 2);
284
285    if (h->num_rects) {
286        for (clut_id = 0; clut_id < h->num_rects; clut_id++) {
287
288            /* CLUT segment */
289
290            if (h->rects[clut_id]->nb_colors <= 4) {
291                /* 2 bpp, some decoders do not support it correctly */
292                bpp_index = 0;
293            } else if (h->rects[clut_id]->nb_colors <= 16) {
294                /* 4 bpp, standard encoding */
295                bpp_index = 1;
296            } else if (h->rects[clut_id]->nb_colors <= 256) {
297                /* 8 bpp, standard encoding */
298                bpp_index = 2;
299            } else {
300                return -1;
301            }
302
303
304            /* CLUT segment */
305            *q++ = 0x0f; /* sync byte */
306            *q++ = 0x12; /* CLUT definition segment */
307            bytestream_put_be16(&q, page_id);
308            pseg_len = q;
309            q += 2; /* segment length */
310            *q++ = clut_id;
311            *q++ = (0 << 4) | 0xf; /* version = 0 */
312
313            for(i = 0; i < h->rects[clut_id]->nb_colors; i++) {
314                *q++ = i; /* clut_entry_id */
315                *q++ = (1 << (7 - bpp_index)) | (0xf << 1) | 1; /* 2 bits/pixel full range */
316                {
317                    int a, r, g, b;
318                    uint32_t x= ((uint32_t*)h->rects[clut_id]->pict.data[1])[i];
319                    a = (x >> 24) & 0xff;
320                    r = (x >> 16) & 0xff;
321                    g = (x >>  8) & 0xff;
322                    b = (x >>  0) & 0xff;
323
324                    *q++ = RGB_TO_Y_CCIR(r, g, b);
325                    *q++ = RGB_TO_V_CCIR(r, g, b, 0);
326                    *q++ = RGB_TO_U_CCIR(r, g, b, 0);
327                    *q++ = 255 - a;
328                }
329            }
330
331            bytestream_put_be16(&pseg_len, q - pseg_len - 2);
332        }
333    }
334
335    for (region_id = 0; region_id < h->num_rects; region_id++) {
336
337        /* region composition segment */
338
339        if (h->rects[region_id]->nb_colors <= 4) {
340            /* 2 bpp, some decoders do not support it correctly */
341            bpp_index = 0;
342        } else if (h->rects[region_id]->nb_colors <= 16) {
343            /* 4 bpp, standard encoding */
344            bpp_index = 1;
345        } else {
346            return -1;
347        }
348
349        *q++ = 0x0f; /* sync_byte */
350        *q++ = 0x11; /* segment_type */
351        bytestream_put_be16(&q, page_id);
352        pseg_len = q;
353        q += 2; /* segment length */
354        *q++ = region_id;
355        *q++ = (s->object_version << 4) | (0 << 3) | 0x07; /* version , no fill */
356        bytestream_put_be16(&q, h->rects[region_id]->w); /* region width */
357        bytestream_put_be16(&q, h->rects[region_id]->h); /* region height */
358        *q++ = ((1 + bpp_index) << 5) | ((1 + bpp_index) << 2) | 0x03;
359        *q++ = region_id; /* clut_id == region_id */
360        *q++ = 0; /* 8 bit fill colors */
361        *q++ = 0x03; /* 4 bit and 2 bit fill colors */
362
363        bytestream_put_be16(&q, region_id); /* object_id == region_id */
364        *q++ = (0 << 6) | (0 << 4);
365        *q++ = 0;
366        *q++ = 0xf0;
367        *q++ = 0;
368
369        bytestream_put_be16(&pseg_len, q - pseg_len - 2);
370    }
371
372    if (h->num_rects) {
373
374        for (object_id = 0; object_id < h->num_rects; object_id++) {
375            void (*dvb_encode_rle)(uint8_t **pq,
376                                    const uint8_t *bitmap, int linesize,
377                                    int w, int h);
378
379            /* bpp_index maths */
380            if (h->rects[object_id]->nb_colors <= 4) {
381                /* 2 bpp, some decoders do not support it correctly */
382                dvb_encode_rle = dvb_encode_rle2;
383            } else if (h->rects[object_id]->nb_colors <= 16) {
384                /* 4 bpp, standard encoding */
385                dvb_encode_rle = dvb_encode_rle4;
386            } else if (h->rects[object_id]->nb_colors <= 256) {
387                /* 8 bpp, standard encoding */
388                dvb_encode_rle = dvb_encode_rle8;
389            } else {
390                return -1;
391            }
392
393            /* Object Data segment */
394            *q++ = 0x0f; /* sync byte */
395            *q++ = 0x13;
396            bytestream_put_be16(&q, page_id);
397            pseg_len = q;
398            q += 2; /* segment length */
399
400            bytestream_put_be16(&q, object_id);
401            *q++ = (s->object_version << 4) | (0 << 2) | (0 << 1) | 1; /* version = 0,
402                                                                       onject_coding_method,
403                                                                       non_modifying_color_flag */
404            {
405                uint8_t *ptop_field_len, *pbottom_field_len, *top_ptr, *bottom_ptr;
406
407                ptop_field_len = q;
408                q += 2;
409                pbottom_field_len = q;
410                q += 2;
411
412                top_ptr = q;
413                dvb_encode_rle(&q, h->rects[object_id]->pict.data[0], h->rects[object_id]->w * 2,
414                                    h->rects[object_id]->w, h->rects[object_id]->h >> 1);
415                bottom_ptr = q;
416                dvb_encode_rle(&q, h->rects[object_id]->pict.data[0] + h->rects[object_id]->w,
417                                    h->rects[object_id]->w * 2, h->rects[object_id]->w,
418                                    h->rects[object_id]->h >> 1);
419
420                bytestream_put_be16(&ptop_field_len, bottom_ptr - top_ptr);
421                bytestream_put_be16(&pbottom_field_len, q - bottom_ptr);
422            }
423
424            bytestream_put_be16(&pseg_len, q - pseg_len - 2);
425        }
426    }
427
428    /* end of display set segment */
429
430    *q++ = 0x0f; /* sync_byte */
431    *q++ = 0x80; /* segment_type */
432    bytestream_put_be16(&q, page_id);
433    pseg_len = q;
434    q += 2; /* segment length */
435
436    bytestream_put_be16(&pseg_len, q - pseg_len - 2);
437
438    s->object_version = (s->object_version + 1) & 0xf;
439    return q - outbuf;
440}
441
442static int dvbsub_encode(AVCodecContext *avctx,
443                         unsigned char *buf, int buf_size,
444                         const AVSubtitle *sub)
445{
446    DVBSubtitleContext *s = avctx->priv_data;
447    int ret;
448
449    ret = encode_dvb_subtitles(s, buf, sub);
450    return ret;
451}
452
453AVCodec ff_dvbsub_encoder = {
454    .name           = "dvbsub",
455    .long_name      = NULL_IF_CONFIG_SMALL("DVB subtitles"),
456    .type           = AVMEDIA_TYPE_SUBTITLE,
457    .id             = AV_CODEC_ID_DVB_SUBTITLE,
458    .priv_data_size = sizeof(DVBSubtitleContext),
459    .encode_sub     = dvbsub_encode,
460};
461