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/libavcodec/dvbsub.c

http://github.com/FFmpeg/FFmpeg
C | 529 lines | 421 code | 56 blank | 52 comment | 110 complexity | 4f76ff7fdc6c1efeb9e6a6f6ae0bab31 MD5 | raw file
  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 int dvb_encode_rle2(uint8_t **pq, int buf_size,
 41                           const uint8_t *bitmap, int linesize,
 42                           int w, int h)
 43{
 44    uint8_t *q, *line_begin;
 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        // Worst case line is 3 bits per value + 4 bytes overhead
 53        if (buf_size * 8 < w * 3 + 32)
 54            return AVERROR_BUFFER_TOO_SMALL;
 55        line_begin = q;
 56        *q++ = 0x10;
 57        bitbuf = 0;
 58        bitcnt = 6;
 59
 60        x = 0;
 61        while (x < w) {
 62            x1 = x;
 63            color = bitmap[x1++];
 64            while (x1 < w && bitmap[x1] == color)
 65                x1++;
 66            len = x1 - x;
 67            if (color == 0 && len == 2) {
 68                PUTBITS2(0);
 69                PUTBITS2(0);
 70                PUTBITS2(1);
 71            } else if (len >= 3 && len <= 10) {
 72                v = len - 3;
 73                PUTBITS2(0);
 74                PUTBITS2((v >> 2) | 2);
 75                PUTBITS2(v & 3);
 76                PUTBITS2(color);
 77            } else if (len >= 12 && len <= 27) {
 78                v = len - 12;
 79                PUTBITS2(0);
 80                PUTBITS2(0);
 81                PUTBITS2(2);
 82                PUTBITS2(v >> 2);
 83                PUTBITS2(v & 3);
 84                PUTBITS2(color);
 85            } else if (len >= 29) {
 86                /* length = 29 ... 284 */
 87                if (len > 284)
 88                    len = 284;
 89                v = len - 29;
 90                PUTBITS2(0);
 91                PUTBITS2(0);
 92                PUTBITS2(3);
 93                PUTBITS2((v >> 6));
 94                PUTBITS2((v >> 4) & 3);
 95                PUTBITS2((v >> 2) & 3);
 96                PUTBITS2(v & 3);
 97                PUTBITS2(color);
 98            } else {
 99                PUTBITS2(color);
100                if (color == 0) {
101                    PUTBITS2(1);
102                }
103                len = 1;
104            }
105            x += len;
106        }
107        /* end of line */
108        PUTBITS2(0);
109        PUTBITS2(0);
110        PUTBITS2(0);
111        if (bitcnt != 6) {
112            *q++ = bitbuf;
113        }
114        *q++ = 0xf0;
115        bitmap += linesize;
116        buf_size -= q - line_begin;
117    }
118    len = q - *pq;
119    *pq = q;
120    return len;
121}
122
123#define PUTBITS4(val)\
124{\
125    bitbuf |= (val) << bitcnt;\
126    bitcnt -= 4;\
127    if (bitcnt < 0) {\
128        bitcnt = 4;\
129        *q++ = bitbuf;\
130        bitbuf = 0;\
131    }\
132}
133
134/* some DVB decoders only implement 4 bits/pixel */
135static int dvb_encode_rle4(uint8_t **pq, int buf_size,
136                           const uint8_t *bitmap, int linesize,
137                           int w, int h)
138{
139    uint8_t *q, *line_begin;
140    unsigned int bitbuf;
141    int bitcnt;
142    int x, y, len, x1, v, color;
143
144    q = *pq;
145
146    for(y = 0; y < h; y++) {
147        // Worst case line is 6 bits per value, + 4 bytes overhead
148        if (buf_size * 8 < w * 6 + 32)
149            return AVERROR_BUFFER_TOO_SMALL;
150        line_begin = q;
151        *q++ = 0x11;
152        bitbuf = 0;
153        bitcnt = 4;
154
155        x = 0;
156        while (x < w) {
157            x1 = x;
158            color = bitmap[x1++];
159            while (x1 < w && bitmap[x1] == color)
160                x1++;
161            len = x1 - x;
162            if (color == 0 && len == 2) {
163                PUTBITS4(0);
164                PUTBITS4(0xd);
165            } else if (color == 0 && (len >= 3 && len <= 9)) {
166                PUTBITS4(0);
167                PUTBITS4(len - 2);
168            } else if (len >= 4 && len <= 7) {
169                PUTBITS4(0);
170                PUTBITS4(8 + len - 4);
171                PUTBITS4(color);
172            } else if (len >= 9 && len <= 24) {
173                PUTBITS4(0);
174                PUTBITS4(0xe);
175                PUTBITS4(len - 9);
176                PUTBITS4(color);
177            } else if (len >= 25) {
178                if (len > 280)
179                    len = 280;
180                v = len - 25;
181                PUTBITS4(0);
182                PUTBITS4(0xf);
183                PUTBITS4(v >> 4);
184                PUTBITS4(v & 0xf);
185                PUTBITS4(color);
186            } else {
187                PUTBITS4(color);
188                if (color == 0) {
189                    PUTBITS4(0xc);
190                }
191                len = 1;
192            }
193            x += len;
194        }
195        /* end of line */
196        PUTBITS4(0);
197        PUTBITS4(0);
198        if (bitcnt != 4) {
199            *q++ = bitbuf;
200        }
201        *q++ = 0xf0;
202        bitmap += linesize;
203        buf_size -= q - line_begin;
204    }
205    len = q - *pq;
206    *pq = q;
207    return len;
208}
209
210static int dvb_encode_rle8(uint8_t **pq, int buf_size,
211                           const uint8_t *bitmap, int linesize,
212                           int w, int h)
213{
214    uint8_t *q, *line_begin;
215    int x, y, len, x1, color;
216
217    q = *pq;
218
219    for (y = 0; y < h; y++) {
220        // Worst case line is 12 bits per value, + 3 bytes overhead
221        if (buf_size * 8 < w * 12 + 24)
222            return AVERROR_BUFFER_TOO_SMALL;
223        line_begin = q;
224        *q++ = 0x12;
225
226        x = 0;
227        while (x < w) {
228            x1 = x;
229            color = bitmap[x1++];
230            while (x1 < w && bitmap[x1] == color)
231                x1++;
232            len = x1 - x;
233            if (len == 1 && color) {
234                // 00000001 to 11111111           1 pixel in colour x
235                *q++ = color;
236            } else {
237                if (color == 0x00) {
238                    // 00000000 0LLLLLLL          L pixels (1-127) in colour 0 (L > 0)
239                    len = FFMIN(len, 127);
240                    *q++ = 0x00;
241                    *q++ = len;
242                } else if (len > 2) {
243                    // 00000000 1LLLLLLL CCCCCCCC L pixels (3-127) in colour C (L > 2)
244                    len = FFMIN(len, 127);
245                    *q++ = 0x00;
246                    *q++ = 0x80+len;
247                    *q++ = color;
248                }
249                else if (len == 2) {
250                    *q++ = color;
251                    *q++ = color;
252                } else {
253                    *q++ = color;
254                    len = 1;
255                }
256            }
257            x += len;
258        }
259        /* end of line */
260        // 00000000 end of 8-bit/pixel_code_string
261        *q++ = 0x00;
262        *q++ = 0xf0;
263        bitmap += linesize;
264        buf_size -= q - line_begin;
265    }
266    len = q - *pq;
267    *pq = q;
268    return len;
269}
270
271static int encode_dvb_subtitles(AVCodecContext *avctx,
272                                uint8_t *outbuf, int buf_size,
273                                const AVSubtitle *h)
274{
275    DVBSubtitleContext *s = avctx->priv_data;
276    uint8_t *q, *pseg_len;
277    int page_id, region_id, clut_id, object_id, i, bpp_index, page_state;
278
279
280    q = outbuf;
281
282    page_id = 1;
283
284    if (h->num_rects && !h->rects)
285        return AVERROR(EINVAL);
286
287    if (avctx->width > 0 && avctx->height > 0) {
288        if (buf_size < 11)
289            return AVERROR_BUFFER_TOO_SMALL;
290        /* display definition segment */
291        *q++ = 0x0f; /* sync_byte */
292        *q++ = 0x14; /* segment_type */
293        bytestream_put_be16(&q, page_id);
294        pseg_len = q;
295        q += 2; /* segment length */
296        *q++ = 0x00; /* dds version number & display window flag */
297        bytestream_put_be16(&q, avctx->width - 1); /* display width */
298        bytestream_put_be16(&q, avctx->height - 1); /* display height */
299        bytestream_put_be16(&pseg_len, q - pseg_len - 2);
300        buf_size -= 11;
301    }
302
303    /* page composition segment */
304
305    if (buf_size < 8 + h->num_rects * 6)
306        return AVERROR_BUFFER_TOO_SMALL;
307    *q++ = 0x0f; /* sync_byte */
308    *q++ = 0x10; /* segment_type */
309    bytestream_put_be16(&q, page_id);
310    pseg_len = q;
311    q += 2; /* segment length */
312    *q++ = 30; /* page_timeout (seconds) */
313    page_state = 2; /* mode change */
314    /* page_version = 0 + page_state */
315    *q++ = (s->object_version << 4) | (page_state << 2) | 3;
316
317    for (region_id = 0; region_id < h->num_rects; region_id++) {
318        *q++ = region_id;
319        *q++ = 0xff; /* reserved */
320        bytestream_put_be16(&q, h->rects[region_id]->x); /* left pos */
321        bytestream_put_be16(&q, h->rects[region_id]->y); /* top pos */
322    }
323
324    bytestream_put_be16(&pseg_len, q - pseg_len - 2);
325    buf_size -= 8 + h->num_rects * 6;
326
327    if (h->num_rects) {
328        for (clut_id = 0; clut_id < h->num_rects; clut_id++) {
329            if (buf_size < 6 + h->rects[clut_id]->nb_colors * 6)
330                return AVERROR_BUFFER_TOO_SMALL;
331
332            /* CLUT segment */
333
334            if (h->rects[clut_id]->nb_colors <= 4) {
335                /* 2 bpp, some decoders do not support it correctly */
336                bpp_index = 0;
337            } else if (h->rects[clut_id]->nb_colors <= 16) {
338                /* 4 bpp, standard encoding */
339                bpp_index = 1;
340            } else if (h->rects[clut_id]->nb_colors <= 256) {
341                /* 8 bpp, standard encoding */
342                bpp_index = 2;
343            } else {
344                return AVERROR(EINVAL);
345            }
346
347
348            /* CLUT segment */
349            *q++ = 0x0f; /* sync byte */
350            *q++ = 0x12; /* CLUT definition segment */
351            bytestream_put_be16(&q, page_id);
352            pseg_len = q;
353            q += 2; /* segment length */
354            *q++ = clut_id;
355            *q++ = (0 << 4) | 0xf; /* version = 0 */
356
357            for(i = 0; i < h->rects[clut_id]->nb_colors; i++) {
358                *q++ = i; /* clut_entry_id */
359                *q++ = (1 << (7 - bpp_index)) | (0xf << 1) | 1; /* 2 bits/pixel full range */
360                {
361                    int a, r, g, b;
362                    uint32_t x= ((uint32_t*)h->rects[clut_id]->data[1])[i];
363                    a = (x >> 24) & 0xff;
364                    r = (x >> 16) & 0xff;
365                    g = (x >>  8) & 0xff;
366                    b = (x >>  0) & 0xff;
367
368                    *q++ = RGB_TO_Y_CCIR(r, g, b);
369                    *q++ = RGB_TO_V_CCIR(r, g, b, 0);
370                    *q++ = RGB_TO_U_CCIR(r, g, b, 0);
371                    *q++ = 255 - a;
372                }
373            }
374
375            bytestream_put_be16(&pseg_len, q - pseg_len - 2);
376            buf_size -= 6 + h->rects[clut_id]->nb_colors * 6;
377        }
378    }
379
380    if (buf_size < h->num_rects * 22)
381        return AVERROR_BUFFER_TOO_SMALL;
382    for (region_id = 0; region_id < h->num_rects; region_id++) {
383
384        /* region composition segment */
385
386        if (h->rects[region_id]->nb_colors <= 4) {
387            /* 2 bpp, some decoders do not support it correctly */
388            bpp_index = 0;
389        } else if (h->rects[region_id]->nb_colors <= 16) {
390            /* 4 bpp, standard encoding */
391            bpp_index = 1;
392        } else if (h->rects[region_id]->nb_colors <= 256) {
393            /* 8 bpp, standard encoding */
394            bpp_index = 2;
395        } else {
396            return AVERROR(EINVAL);
397        }
398
399        *q++ = 0x0f; /* sync_byte */
400        *q++ = 0x11; /* segment_type */
401        bytestream_put_be16(&q, page_id);
402        pseg_len = q;
403        q += 2; /* segment length */
404        *q++ = region_id;
405        *q++ = (s->object_version << 4) | (0 << 3) | 0x07; /* version , no fill */
406        bytestream_put_be16(&q, h->rects[region_id]->w); /* region width */
407        bytestream_put_be16(&q, h->rects[region_id]->h); /* region height */
408        *q++ = ((1 + bpp_index) << 5) | ((1 + bpp_index) << 2) | 0x03;
409        *q++ = region_id; /* clut_id == region_id */
410        *q++ = 0; /* 8 bit fill colors */
411        *q++ = 0x03; /* 4 bit and 2 bit fill colors */
412
413        bytestream_put_be16(&q, region_id); /* object_id == region_id */
414        *q++ = (0 << 6) | (0 << 4);
415        *q++ = 0;
416        *q++ = 0xf0;
417        *q++ = 0;
418
419        bytestream_put_be16(&pseg_len, q - pseg_len - 2);
420    }
421    buf_size -= h->num_rects * 22;
422
423    if (h->num_rects) {
424
425        for (object_id = 0; object_id < h->num_rects; object_id++) {
426            int (*dvb_encode_rle)(uint8_t **pq, int buf_size,
427                                  const uint8_t *bitmap, int linesize,
428                                  int w, int h);
429
430            if (buf_size < 13)
431                return AVERROR_BUFFER_TOO_SMALL;
432
433            /* bpp_index maths */
434            if (h->rects[object_id]->nb_colors <= 4) {
435                /* 2 bpp, some decoders do not support it correctly */
436                dvb_encode_rle = dvb_encode_rle2;
437            } else if (h->rects[object_id]->nb_colors <= 16) {
438                /* 4 bpp, standard encoding */
439                dvb_encode_rle = dvb_encode_rle4;
440            } else if (h->rects[object_id]->nb_colors <= 256) {
441                /* 8 bpp, standard encoding */
442                dvb_encode_rle = dvb_encode_rle8;
443            } else {
444                return AVERROR(EINVAL);
445            }
446
447            /* Object Data segment */
448            *q++ = 0x0f; /* sync byte */
449            *q++ = 0x13;
450            bytestream_put_be16(&q, page_id);
451            pseg_len = q;
452            q += 2; /* segment length */
453
454            bytestream_put_be16(&q, object_id);
455            *q++ = (s->object_version << 4) | (0 << 2) | (0 << 1) | 1; /* version = 0,
456                                                                       onject_coding_method,
457                                                                       non_modifying_color_flag */
458            {
459                uint8_t *ptop_field_len, *pbottom_field_len, *top_ptr, *bottom_ptr;
460                int ret;
461
462                ptop_field_len = q;
463                q += 2;
464                pbottom_field_len = q;
465                q += 2;
466                buf_size -= 13;
467
468                top_ptr = q;
469                ret = dvb_encode_rle(&q, buf_size,
470                                     h->rects[object_id]->data[0],
471                                     h->rects[object_id]->w * 2,
472                                     h->rects[object_id]->w,
473                                     h->rects[object_id]->h >> 1);
474                if (ret < 0)
475                    return ret;
476                buf_size -= ret;
477                bottom_ptr = q;
478                ret = dvb_encode_rle(&q, buf_size,
479                                     h->rects[object_id]->data[0] + h->rects[object_id]->w,
480                                     h->rects[object_id]->w * 2,
481                                     h->rects[object_id]->w,
482                                     h->rects[object_id]->h >> 1);
483                if (ret < 0)
484                    return ret;
485                buf_size -= ret;
486
487                bytestream_put_be16(&ptop_field_len, bottom_ptr - top_ptr);
488                bytestream_put_be16(&pbottom_field_len, q - bottom_ptr);
489            }
490
491            bytestream_put_be16(&pseg_len, q - pseg_len - 2);
492        }
493    }
494
495    /* end of display set segment */
496
497    if (buf_size < 6)
498        return AVERROR_BUFFER_TOO_SMALL;
499    *q++ = 0x0f; /* sync_byte */
500    *q++ = 0x80; /* segment_type */
501    bytestream_put_be16(&q, page_id);
502    pseg_len = q;
503    q += 2; /* segment length */
504
505    bytestream_put_be16(&pseg_len, q - pseg_len - 2);
506    buf_size -= 6;
507
508    s->object_version = (s->object_version + 1) & 0xf;
509    return q - outbuf;
510}
511
512static int dvbsub_encode(AVCodecContext *avctx,
513                         unsigned char *buf, int buf_size,
514                         const AVSubtitle *sub)
515{
516    int ret;
517
518    ret = encode_dvb_subtitles(avctx, buf, buf_size, sub);
519    return ret;
520}
521
522AVCodec ff_dvbsub_encoder = {
523    .name           = "dvbsub",
524    .long_name      = NULL_IF_CONFIG_SMALL("DVB subtitles"),
525    .type           = AVMEDIA_TYPE_SUBTITLE,
526    .id             = AV_CODEC_ID_DVB_SUBTITLE,
527    .priv_data_size = sizeof(DVBSubtitleContext),
528    .encode_sub     = dvbsub_encode,
529};