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