FFmpeg: libavcodec/dvbsub.c Source File

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