FFmpeg: libavcodec/dvbsub.c Source File

00001 /*
00002  * DVB subtitle encoding for ffmpeg
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 int encode_dvb_subtitles(DVBSubtitleContext *s,
00198                                 uint8_t *outbuf, AVSubtitle *h)
00199 {
00200     uint8_t *q, *pseg_len;
00201     int page_id, region_id, clut_id, object_id, i, bpp_index, page_state;
00202 
00203 
00204     q = outbuf;
00205 
00206     page_id = 1;
00207 
00208     if (h->num_rects == 0 || h->rects == NULL)
00209         return -1;
00210 
00211     *q++ = 0x00; /* subtitle_stream_id */
00212 
00213     /* page composition segment */
00214 
00215     *q++ = 0x0f; /* sync_byte */
00216     *q++ = 0x10; /* segment_type */
00217     bytestream_put_be16(&q, page_id);
00218     pseg_len = q;
00219     q += 2; /* segment length */
00220     *q++ = 30; /* page_timeout (seconds) */
00221     if (s->hide_state)
00222         page_state = 0; /* normal case */
00223     else
00224         page_state = 2; /* mode change */
00225     /* page_version = 0 + page_state */
00226     *q++ = (s->object_version << 4) | (page_state << 2) | 3;
00227 
00228     for (region_id = 0; region_id < h->num_rects; region_id++) {
00229         *q++ = region_id;
00230         *q++ = 0xff; /* reserved */
00231         bytestream_put_be16(&q, h->rects[region_id]->x); /* left pos */
00232         bytestream_put_be16(&q, h->rects[region_id]->y); /* top pos */
00233     }
00234 
00235     bytestream_put_be16(&pseg_len, q - pseg_len - 2);
00236 
00237     if (!s->hide_state) {
00238         for (clut_id = 0; clut_id < h->num_rects; clut_id++) {
00239 
00240             /* CLUT segment */
00241 
00242             if (h->rects[clut_id]->nb_colors <= 4) {
00243                 /* 2 bpp, some decoders do not support it correctly */
00244                 bpp_index = 0;
00245             } else if (h->rects[clut_id]->nb_colors <= 16) {
00246                 /* 4 bpp, standard encoding */
00247                 bpp_index = 1;
00248             } else {
00249                 return -1;
00250             }
00251 
00252             *q++ = 0x0f; /* sync byte */
00253             *q++ = 0x12; /* CLUT definition segment */
00254             bytestream_put_be16(&q, page_id);
00255             pseg_len = q;
00256             q += 2; /* segment length */
00257             *q++ = clut_id;
00258             *q++ = (0 << 4) | 0xf; /* version = 0 */
00259 
00260             for(i = 0; i < h->rects[clut_id]->nb_colors; i++) {
00261                 *q++ = i; /* clut_entry_id */
00262                 *q++ = (1 << (7 - bpp_index)) | (0xf << 1) | 1; /* 2 bits/pixel full range */
00263                 {
00264                     int a, r, g, b;
00265                     uint32_t x= ((uint32_t*)h->rects[clut_id]->pict.data[1])[i];
00266                     a = (x >> 24) & 0xff;
00267                     r = (x >> 16) & 0xff;
00268                     g = (x >>  8) & 0xff;
00269                     b = (x >>  0) & 0xff;
00270 
00271                     *q++ = RGB_TO_Y_CCIR(r, g, b);
00272                     *q++ = RGB_TO_V_CCIR(r, g, b, 0);
00273                     *q++ = RGB_TO_U_CCIR(r, g, b, 0);
00274                     *q++ = 255 - a;
00275                 }
00276             }
00277 
00278             bytestream_put_be16(&pseg_len, q - pseg_len - 2);
00279         }
00280     }
00281 
00282     for (region_id = 0; region_id < h->num_rects; region_id++) {
00283 
00284         /* region composition segment */
00285 
00286         if (h->rects[region_id]->nb_colors <= 4) {
00287             /* 2 bpp, some decoders do not support it correctly */
00288             bpp_index = 0;
00289         } else if (h->rects[region_id]->nb_colors <= 16) {
00290             /* 4 bpp, standard encoding */
00291             bpp_index = 1;
00292         } else {
00293             return -1;
00294         }
00295 
00296         *q++ = 0x0f; /* sync_byte */
00297         *q++ = 0x11; /* segment_type */
00298         bytestream_put_be16(&q, page_id);
00299         pseg_len = q;
00300         q += 2; /* segment length */
00301         *q++ = region_id;
00302         *q++ = (s->object_version << 4) | (0 << 3) | 0x07; /* version , no fill */
00303         bytestream_put_be16(&q, h->rects[region_id]->w); /* region width */
00304         bytestream_put_be16(&q, h->rects[region_id]->h); /* region height */
00305         *q++ = ((1 + bpp_index) << 5) | ((1 + bpp_index) << 2) | 0x03;
00306         *q++ = region_id; /* clut_id == region_id */
00307         *q++ = 0; /* 8 bit fill colors */
00308         *q++ = 0x03; /* 4 bit and 2 bit fill colors */
00309 
00310         if (!s->hide_state) {
00311             bytestream_put_be16(&q, region_id); /* object_id == region_id */
00312             *q++ = (0 << 6) | (0 << 4);
00313             *q++ = 0;
00314             *q++ = 0xf0;
00315             *q++ = 0;
00316         }
00317 
00318         bytestream_put_be16(&pseg_len, q - pseg_len - 2);
00319     }
00320 
00321     if (!s->hide_state) {
00322 
00323         for (object_id = 0; object_id < h->num_rects; object_id++) {
00324             /* Object Data segment */
00325 
00326             if (h->rects[object_id]->nb_colors <= 4) {
00327                 /* 2 bpp, some decoders do not support it correctly */
00328                 bpp_index = 0;
00329             } else if (h->rects[object_id]->nb_colors <= 16) {
00330                 /* 4 bpp, standard encoding */
00331                 bpp_index = 1;
00332             } else {
00333                 return -1;
00334             }
00335 
00336             *q++ = 0x0f; /* sync byte */
00337             *q++ = 0x13;
00338             bytestream_put_be16(&q, page_id);
00339             pseg_len = q;
00340             q += 2; /* segment length */
00341 
00342             bytestream_put_be16(&q, object_id);
00343             *q++ = (s->object_version << 4) | (0 << 2) | (0 << 1) | 1; /* version = 0,
00344                                                                        onject_coding_method,
00345                                                                        non_modifying_color_flag */
00346             {
00347                 uint8_t *ptop_field_len, *pbottom_field_len, *top_ptr, *bottom_ptr;
00348                 void (*dvb_encode_rle)(uint8_t **pq,
00349                                         const uint8_t *bitmap, int linesize,
00350                                         int w, int h);
00351                 ptop_field_len = q;
00352                 q += 2;
00353                 pbottom_field_len = q;
00354                 q += 2;
00355 
00356                 if (bpp_index == 0)
00357                     dvb_encode_rle = dvb_encode_rle2;
00358                 else
00359                     dvb_encode_rle = dvb_encode_rle4;
00360 
00361                 top_ptr = q;
00362                 dvb_encode_rle(&q, h->rects[object_id]->pict.data[0], h->rects[object_id]->w * 2,
00363                                     h->rects[object_id]->w, h->rects[object_id]->h >> 1);
00364                 bottom_ptr = q;
00365                 dvb_encode_rle(&q, h->rects[object_id]->pict.data[0] + h->rects[object_id]->w,
00366                                     h->rects[object_id]->w * 2, h->rects[object_id]->w,
00367                                     h->rects[object_id]->h >> 1);
00368 
00369                 bytestream_put_be16(&ptop_field_len, bottom_ptr - top_ptr);
00370                 bytestream_put_be16(&pbottom_field_len, q - bottom_ptr);
00371             }
00372 
00373             bytestream_put_be16(&pseg_len, q - pseg_len - 2);
00374         }
00375     }
00376 
00377     /* end of display set segment */
00378 
00379     *q++ = 0x0f; /* sync_byte */
00380     *q++ = 0x80; /* segment_type */
00381     bytestream_put_be16(&q, page_id);
00382     pseg_len = q;
00383     q += 2; /* segment length */
00384 
00385     bytestream_put_be16(&pseg_len, q - pseg_len - 2);
00386 
00387     *q++ = 0xff; /* end of PES data */
00388 
00389     s->object_version = (s->object_version + 1) & 0xf;
00390     s->hide_state = !s->hide_state;
00391     return q - outbuf;
00392 }
00393 
00394 static int dvbsub_encode(AVCodecContext *avctx,
00395                        unsigned char *buf, int buf_size, void *data)
00396 {
00397     DVBSubtitleContext *s = avctx->priv_data;
00398     AVSubtitle *sub = data;
00399     int ret;
00400 
00401     ret = encode_dvb_subtitles(s, buf, sub);
00402     return ret;
00403 }
00404 
00405 AVCodec ff_dvbsub_encoder = {
00406     "dvbsub",
00407     AVMEDIA_TYPE_SUBTITLE,
00408     CODEC_ID_DVB_SUBTITLE,
00409     sizeof(DVBSubtitleContext),
00410     NULL,
00411     dvbsub_encode,
00412     .long_name = NULL_IF_CONFIG_SMALL("DVB subtitles"),
00413 };