libavcodec/dvbsub.c
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00001 /*
00002  * DVB subtitle encoding
00003  * Copyright (c) 2005 Fabrice Bellard
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 #include "avcodec.h"
00022 #include "bytestream.h"
00023 #include "libavutil/colorspace.h"
00024 
00025 typedef struct DVBSubtitleContext {
00026     int hide_state;
00027     int object_version;
00028 } DVBSubtitleContext;
00029 
00030 #define PUTBITS2(val)\
00031 {\
00032     bitbuf |= (val) << bitcnt;\
00033     bitcnt -= 2;\
00034     if (bitcnt < 0) {\
00035         bitcnt = 6;\
00036         *q++ = bitbuf;\
00037         bitbuf = 0;\
00038     }\
00039 }
00040 
00041 static void dvb_encode_rle2(uint8_t **pq,
00042                             const uint8_t *bitmap, int linesize,
00043                             int w, int h)
00044 {
00045     uint8_t *q;
00046     unsigned int bitbuf;
00047     int bitcnt;
00048     int x, y, len, x1, v, color;
00049 
00050     q = *pq;
00051 
00052     for(y = 0; y < h; y++) {
00053         *q++ = 0x10;
00054         bitbuf = 0;
00055         bitcnt = 6;
00056 
00057         x = 0;
00058         while (x < w) {
00059             x1 = x;
00060             color = bitmap[x1++];
00061             while (x1 < w && bitmap[x1] == color)
00062                 x1++;
00063             len = x1 - x;
00064             if (color == 0 && len == 2) {
00065                 PUTBITS2(0);
00066                 PUTBITS2(0);
00067                 PUTBITS2(1);
00068             } else if (len >= 3 && len <= 10) {
00069                 v = len - 3;
00070                 PUTBITS2(0);
00071                 PUTBITS2((v >> 2) | 2);
00072                 PUTBITS2(v & 3);
00073                 PUTBITS2(color);
00074             } else if (len >= 12 && len <= 27) {
00075                 v = len - 12;
00076                 PUTBITS2(0);
00077                 PUTBITS2(0);
00078                 PUTBITS2(2);
00079                 PUTBITS2(v >> 2);
00080                 PUTBITS2(v & 3);
00081                 PUTBITS2(color);
00082             } else if (len >= 29) {
00083                 /* length = 29 ... 284 */
00084                 if (len > 284)
00085                     len = 284;
00086                 v = len - 29;
00087                 PUTBITS2(0);
00088                 PUTBITS2(0);
00089                 PUTBITS2(3);
00090                 PUTBITS2((v >> 6));
00091                 PUTBITS2((v >> 4) & 3);
00092                 PUTBITS2((v >> 2) & 3);
00093                 PUTBITS2(v & 3);
00094                 PUTBITS2(color);
00095             } else {
00096                 PUTBITS2(color);
00097                 if (color == 0) {
00098                     PUTBITS2(1);
00099                 }
00100                 len = 1;
00101             }
00102             x += len;
00103         }
00104         /* end of line */
00105         PUTBITS2(0);
00106         PUTBITS2(0);
00107         PUTBITS2(0);
00108         if (bitcnt != 6) {
00109             *q++ = bitbuf;
00110         }
00111         *q++ = 0xf0;
00112         bitmap += linesize;
00113     }
00114     *pq = q;
00115 }
00116 
00117 #define PUTBITS4(val)\
00118 {\
00119     bitbuf |= (val) << bitcnt;\
00120     bitcnt -= 4;\
00121     if (bitcnt < 0) {\
00122         bitcnt = 4;\
00123         *q++ = bitbuf;\
00124         bitbuf = 0;\
00125     }\
00126 }
00127 
00128 /* some DVB decoders only implement 4 bits/pixel */
00129 static void dvb_encode_rle4(uint8_t **pq,
00130                             const uint8_t *bitmap, int linesize,
00131                             int w, int h)
00132 {
00133     uint8_t *q;
00134     unsigned int bitbuf;
00135     int bitcnt;
00136     int x, y, len, x1, v, color;
00137 
00138     q = *pq;
00139 
00140     for(y = 0; y < h; y++) {
00141         *q++ = 0x11;
00142         bitbuf = 0;
00143         bitcnt = 4;
00144 
00145         x = 0;
00146         while (x < w) {
00147             x1 = x;
00148             color = bitmap[x1++];
00149             while (x1 < w && bitmap[x1] == color)
00150                 x1++;
00151             len = x1 - x;
00152             if (color == 0 && len == 2) {
00153                 PUTBITS4(0);
00154                 PUTBITS4(0xd);
00155             } else if (color == 0 && (len >= 3 && len <= 9)) {
00156                 PUTBITS4(0);
00157                 PUTBITS4(len - 2);
00158             } else if (len >= 4 && len <= 7) {
00159                 PUTBITS4(0);
00160                 PUTBITS4(8 + len - 4);
00161                 PUTBITS4(color);
00162             } else if (len >= 9 && len <= 24) {
00163                 PUTBITS4(0);
00164                 PUTBITS4(0xe);
00165                 PUTBITS4(len - 9);
00166                 PUTBITS4(color);
00167             } else if (len >= 25) {
00168                 if (len > 280)
00169                     len = 280;
00170                 v = len - 25;
00171                 PUTBITS4(0);
00172                 PUTBITS4(0xf);
00173                 PUTBITS4(v >> 4);
00174                 PUTBITS4(v & 0xf);
00175                 PUTBITS4(color);
00176             } else {
00177                 PUTBITS4(color);
00178                 if (color == 0) {
00179                     PUTBITS4(0xc);
00180                 }
00181                 len = 1;
00182             }
00183             x += len;
00184         }
00185         /* end of line */
00186         PUTBITS4(0);
00187         PUTBITS4(0);
00188         if (bitcnt != 4) {
00189             *q++ = bitbuf;
00190         }
00191         *q++ = 0xf0;
00192         bitmap += linesize;
00193     }
00194     *pq = q;
00195 }
00196 
00197 static void dvb_encode_rle8(uint8_t **pq,
00198                             const uint8_t *bitmap, int linesize,
00199                             int w, int h)
00200 {
00201     uint8_t *q;
00202     int x, y, len, x1, f, color;
00203 
00204     q = *pq;
00205 
00206     for (y = 0; y < h; y++) {
00207         *q++ = 0x12;
00208 
00209         x = 0;
00210         f = 0;
00211         while (x < w) {
00212             x1 = x;
00213             color = bitmap[x1++];
00214             while (x1 < w && bitmap[x1] == color)
00215                 x1++;
00216             len = x1 - x;
00217             if (len == 1 && color) {
00218                 // 00000001 to 11111111           1 pixel in colour x
00219                 *q++ = color;
00220             } else {
00221                 if (color == 0x00) {
00222                     // 00000000 0LLLLLLL          L pixels (1-127) in colour 0 (L > 0)
00223                     len = FFMIN(len, 127);
00224                     *q++ = 0x00;
00225                     *q++ = len;
00226                 } else if (len > 2) {
00227                     // 00000000 1LLLLLLL CCCCCCCC L pixels (3-127) in colour C (L > 2)
00228                     len = FFMIN(len, 127);
00229                     *q++ = 0x00;
00230                     *q++ = 0x80+len;
00231                     *q++ = color;
00232                 }
00233                 else if (len == 2) {
00234                     *q++ = color;
00235                     *q++ = color;
00236                 } else {
00237                     *q++ = color;
00238                     len = 1;
00239                 }
00240             }
00241             x += len;
00242         }
00243         /* end of line */
00244         // 00000000 00000000 end of 8-bit/pixel_code_string
00245         *q++ = 0x00;
00246         *q++ = 0x00;
00247         bitmap += linesize;
00248     }
00249     *pq = q;
00250 }
00251 
00252 static int encode_dvb_subtitles(DVBSubtitleContext *s,
00253                                 uint8_t *outbuf, AVSubtitle *h)
00254 {
00255     uint8_t *q, *pseg_len;
00256     int page_id, region_id, clut_id, object_id, i, bpp_index, page_state;
00257 
00258 
00259     q = outbuf;
00260 
00261     page_id = 1;
00262 
00263     if (h->num_rects == 0 || h->rects == NULL)
00264         return -1;
00265 
00266     *q++ = 0x00; /* subtitle_stream_id */
00267 
00268     /* page composition segment */
00269 
00270     *q++ = 0x0f; /* sync_byte */
00271     *q++ = 0x10; /* segment_type */
00272     bytestream_put_be16(&q, page_id);
00273     pseg_len = q;
00274     q += 2; /* segment length */
00275     *q++ = 30; /* page_timeout (seconds) */
00276     if (s->hide_state)
00277         page_state = 0; /* normal case */
00278     else
00279         page_state = 2; /* mode change */
00280     /* page_version = 0 + page_state */
00281     *q++ = (s->object_version << 4) | (page_state << 2) | 3;
00282 
00283     for (region_id = 0; region_id < h->num_rects; region_id++) {
00284         *q++ = region_id;
00285         *q++ = 0xff; /* reserved */
00286         bytestream_put_be16(&q, h->rects[region_id]->x); /* left pos */
00287         bytestream_put_be16(&q, h->rects[region_id]->y); /* top pos */
00288     }
00289 
00290     bytestream_put_be16(&pseg_len, q - pseg_len - 2);
00291 
00292     if (!s->hide_state) {
00293         for (clut_id = 0; clut_id < h->num_rects; clut_id++) {
00294 
00295             /* CLUT segment */
00296 
00297             if (h->rects[clut_id]->nb_colors <= 4) {
00298                 /* 2 bpp, some decoders do not support it correctly */
00299                 bpp_index = 0;
00300             } else if (h->rects[clut_id]->nb_colors <= 16) {
00301                 /* 4 bpp, standard encoding */
00302                 bpp_index = 1;
00303             } else if (h->rects[clut_id]->nb_colors <= 256) {
00304                 /* 8 bpp, standard encoding */
00305                 bpp_index = 2;
00306             } else {
00307                 return -1;
00308             }
00309 
00310 
00311             /* CLUT segment */
00312             *q++ = 0x0f; /* sync byte */
00313             *q++ = 0x12; /* CLUT definition segment */
00314             bytestream_put_be16(&q, page_id);
00315             pseg_len = q;
00316             q += 2; /* segment length */
00317             *q++ = clut_id;
00318             *q++ = (0 << 4) | 0xf; /* version = 0 */
00319 
00320             for(i = 0; i < h->rects[clut_id]->nb_colors; i++) {
00321                 *q++ = i; /* clut_entry_id */
00322                 *q++ = (1 << (7 - bpp_index)) | (0xf << 1) | 1; /* 2 bits/pixel full range */
00323                 {
00324                     int a, r, g, b;
00325                     uint32_t x= ((uint32_t*)h->rects[clut_id]->pict.data[1])[i];
00326                     a = (x >> 24) & 0xff;
00327                     r = (x >> 16) & 0xff;
00328                     g = (x >>  8) & 0xff;
00329                     b = (x >>  0) & 0xff;
00330 
00331                     *q++ = RGB_TO_Y_CCIR(r, g, b);
00332                     *q++ = RGB_TO_V_CCIR(r, g, b, 0);
00333                     *q++ = RGB_TO_U_CCIR(r, g, b, 0);
00334                     *q++ = 255 - a;
00335                 }
00336             }
00337 
00338             bytestream_put_be16(&pseg_len, q - pseg_len - 2);
00339         }
00340     }
00341 
00342     for (region_id = 0; region_id < h->num_rects; region_id++) {
00343 
00344         /* region composition segment */
00345 
00346         if (h->rects[region_id]->nb_colors <= 4) {
00347             /* 2 bpp, some decoders do not support it correctly */
00348             bpp_index = 0;
00349         } else if (h->rects[region_id]->nb_colors <= 16) {
00350             /* 4 bpp, standard encoding */
00351             bpp_index = 1;
00352         } else {
00353             return -1;
00354         }
00355 
00356         *q++ = 0x0f; /* sync_byte */
00357         *q++ = 0x11; /* segment_type */
00358         bytestream_put_be16(&q, page_id);
00359         pseg_len = q;
00360         q += 2; /* segment length */
00361         *q++ = region_id;
00362         *q++ = (s->object_version << 4) | (0 << 3) | 0x07; /* version , no fill */
00363         bytestream_put_be16(&q, h->rects[region_id]->w); /* region width */
00364         bytestream_put_be16(&q, h->rects[region_id]->h); /* region height */
00365         *q++ = ((1 + bpp_index) << 5) | ((1 + bpp_index) << 2) | 0x03;
00366         *q++ = region_id; /* clut_id == region_id */
00367         *q++ = 0; /* 8 bit fill colors */
00368         *q++ = 0x03; /* 4 bit and 2 bit fill colors */
00369 
00370         if (!s->hide_state) {
00371             bytestream_put_be16(&q, region_id); /* object_id == region_id */
00372             *q++ = (0 << 6) | (0 << 4);
00373             *q++ = 0;
00374             *q++ = 0xf0;
00375             *q++ = 0;
00376         }
00377 
00378         bytestream_put_be16(&pseg_len, q - pseg_len - 2);
00379     }
00380 
00381     if (!s->hide_state) {
00382 
00383         for (object_id = 0; object_id < h->num_rects; object_id++) {
00384             void (*dvb_encode_rle)(uint8_t **pq,
00385                                     const uint8_t *bitmap, int linesize,
00386                                     int w, int h);
00387 
00388             /* bpp_index maths */
00389             if (h->rects[object_id]->nb_colors <= 4) {
00390                 /* 2 bpp, some decoders do not support it correctly */
00391                 dvb_encode_rle = dvb_encode_rle2;
00392             } else if (h->rects[object_id]->nb_colors <= 16) {
00393                 /* 4 bpp, standard encoding */
00394                 dvb_encode_rle = dvb_encode_rle4;
00395             } else if (h->rects[object_id]->nb_colors <= 256) {
00396                 /* 8 bpp, standard encoding */
00397                 dvb_encode_rle = dvb_encode_rle8;
00398             } else {
00399                 return -1;
00400             }
00401 
00402             /* Object Data segment */
00403             *q++ = 0x0f; /* sync byte */
00404             *q++ = 0x13;
00405             bytestream_put_be16(&q, page_id);
00406             pseg_len = q;
00407             q += 2; /* segment length */
00408 
00409             bytestream_put_be16(&q, object_id);
00410             *q++ = (s->object_version << 4) | (0 << 2) | (0 << 1) | 1; /* version = 0,
00411                                                                        onject_coding_method,
00412                                                                        non_modifying_color_flag */
00413             {
00414                 uint8_t *ptop_field_len, *pbottom_field_len, *top_ptr, *bottom_ptr;
00415 
00416                 ptop_field_len = q;
00417                 q += 2;
00418                 pbottom_field_len = q;
00419                 q += 2;
00420 
00421                 top_ptr = q;
00422                 dvb_encode_rle(&q, h->rects[object_id]->pict.data[0], h->rects[object_id]->w * 2,
00423                                     h->rects[object_id]->w, h->rects[object_id]->h >> 1);
00424                 bottom_ptr = q;
00425                 dvb_encode_rle(&q, h->rects[object_id]->pict.data[0] + h->rects[object_id]->w,
00426                                     h->rects[object_id]->w * 2, h->rects[object_id]->w,
00427                                     h->rects[object_id]->h >> 1);
00428 
00429                 bytestream_put_be16(&ptop_field_len, bottom_ptr - top_ptr);
00430                 bytestream_put_be16(&pbottom_field_len, q - bottom_ptr);
00431             }
00432 
00433             bytestream_put_be16(&pseg_len, q - pseg_len - 2);
00434         }
00435     }
00436 
00437     /* end of display set segment */
00438 
00439     *q++ = 0x0f; /* sync_byte */
00440     *q++ = 0x80; /* segment_type */
00441     bytestream_put_be16(&q, page_id);
00442     pseg_len = q;
00443     q += 2; /* segment length */
00444 
00445     bytestream_put_be16(&pseg_len, q - pseg_len - 2);
00446 
00447     *q++ = 0xff; /* end of PES data */
00448 
00449     s->object_version = (s->object_version + 1) & 0xf;
00450     s->hide_state = !s->hide_state;
00451     return q - outbuf;
00452 }
00453 
00454 static int dvbsub_encode(AVCodecContext *avctx,
00455                        unsigned char *buf, int buf_size, void *data)
00456 {
00457     DVBSubtitleContext *s = avctx->priv_data;
00458     AVSubtitle *sub = data;
00459     int ret;
00460 
00461     ret = encode_dvb_subtitles(s, buf, sub);
00462     return ret;
00463 }
00464 
00465 AVCodec ff_dvbsub_encoder = {
00466     .name           = "dvbsub",
00467     .type           = AVMEDIA_TYPE_SUBTITLE,
00468     .id             = CODEC_ID_DVB_SUBTITLE,
00469     .priv_data_size = sizeof(DVBSubtitleContext),
00470     .encode         = dvbsub_encode,
00471     .long_name = NULL_IF_CONFIG_SMALL("DVB subtitles"),
00472 };