git.sesse.net Git - ffmpeg/blob - libavcodec/srtdec.c

   1 /*
   2  * SubRip subtitle decoder
   3  * Copyright (c) 2010  Aurelien Jacobs <aurel@gnuage.org>
   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
  22 #include "libavutil/avstring.h"
  23 #include "libavutil/parseutils.h"
  24 #include "avcodec.h"
  25 #include "ass.h"
  26
  27 static int html_color_parse(AVCodecContext *avctx, const char *str)
  28 {
  29     uint8_t rgba[4];
  30     if (av_parse_color(rgba, str, strcspn(str, "\" >"), avctx) < 0)
  31         return -1;
  32     return rgba[0] | rgba[1] << 8 | rgba[2] << 16;
  33 }
  34
  35 enum {
  36     PARAM_UNKNOWN = -1,
  37     PARAM_SIZE,
  38     PARAM_COLOR,
  39     PARAM_FACE,
  40     PARAM_NUMBER
  41 };
  42
  43 typedef struct {
  44     char tag[128];
  45     char param[PARAM_NUMBER][128];
  46 } SrtStack;
  47
  48 static const char *srt_to_ass(AVCodecContext *avctx, char *out, char *out_end,
  49                               const char *in, int x1, int y1, int x2, int y2)
  50 {
  51     char c, *param, buffer[128], tmp[128];
  52     int len, tag_close, sptr = 1, line_start = 1, an = 0, end = 0;
  53     SrtStack stack[16];
  54
  55     stack[0].tag[0] = 0;
  56     strcpy(stack[0].param[PARAM_SIZE],  "{\\fs}");
  57     strcpy(stack[0].param[PARAM_COLOR], "{\\c}");
  58     strcpy(stack[0].param[PARAM_FACE],  "{\\fn}");
  59
  60     if (x1 >= 0 && y1 >= 0) {
  61         if (x2 >= 0 && y2 >= 0 && (x2 != x1 || y2 != y1))
  62             out += snprintf(out, out_end-out,
  63                             "{\\an1}{\\move(%d,%d,%d,%d)}", x1, y1, x2, y2);
  64         else
  65             out += snprintf(out, out_end-out, "{\\an1}{\\pos(%d,%d)}", x1, y1);
  66     }
  67
  68     for (; out < out_end && !end && *in; in++) {
  69         switch (*in) {
  70         case '\r':
  71             break;
  72         case '\n':
  73             if (line_start) {
  74                 end = 1;
  75                 break;
  76             }
  77             while (out[-1] == ' ')
  78                 out--;
  79             out += snprintf(out, out_end-out, "\\N");
  80             line_start = 1;
  81             break;
  82         case ' ':
  83             if (!line_start)
  84                 *out++ = *in;
  85             break;
  86         case '{':    /* skip all {\xxx} substrings except for {\an%d}
  87                         and all microdvd like styles such as {Y:xxx} */
  88             an += sscanf(in, "{\\an%*1u}%c", &c) == 1;
  89             if ((an != 1 && sscanf(in, "{\\%*[^}]}%n%c", &len, &c) > 0) ||
  90                 sscanf(in, "{%*1[CcFfoPSsYy]:%*[^}]}%n%c", &len, &c) > 0) {
  91                 in += len - 1;
  92             } else
  93                 *out++ = *in;
  94             break;
  95         case '<':
  96             tag_close = in[1] == '/';
  97             if (sscanf(in+tag_close+1, "%127[^>]>%n%c", buffer, &len,&c) >= 2) {
  98                 if ((param = strchr(buffer, ' ')))
  99                     *param++ = 0;
 100                 if ((!tag_close && sptr < FF_ARRAY_ELEMS(stack)) ||
 101                     ( tag_close && sptr > 0 && !strcmp(stack[sptr-1].tag, buffer))) {
 102                     int i, j, unknown = 0;
 103                     in += len + tag_close;
 104                     if (!tag_close)
 105                         memset(stack+sptr, 0, sizeof(*stack));
 106                     if (!strcmp(buffer, "font")) {
 107                         if (tag_close) {
 108                             for (i=PARAM_NUMBER-1; i>=0; i--)
 109                                 if (stack[sptr-1].param[i][0])
 110                                     for (j=sptr-2; j>=0; j--)
 111                                         if (stack[j].param[i][0]) {
 112                                             out += snprintf(out, out_end-out,
 113                                                             stack[j].param[i]);
 114                                             break;
 115                                         }
 116                         } else {
 117                             while (param) {
 118                                 if (!strncmp(param, "size=", 5)) {
 119                                     unsigned font_size;
 120                                     param += 5 + (param[5] == '"');
 121                                     if (sscanf(param, "%u", &font_size) == 1) {
 122                                         snprintf(stack[sptr].param[PARAM_SIZE],
 123                                              sizeof(stack[0].param[PARAM_SIZE]),
 124                                              "{\\fs%u}", font_size);
 125                                     }
 126                                 } else if (!strncmp(param, "color=", 6)) {
 127                                     param += 6 + (param[6] == '"');
 128                                     snprintf(stack[sptr].param[PARAM_COLOR],
 129                                          sizeof(stack[0].param[PARAM_COLOR]),
 130                                          "{\\c&H%X&}",
 131                                          html_color_parse(avctx, param));
 132                                 } else if (!strncmp(param, "face=", 5)) {
 133                                     param += 5 + (param[5] == '"');
 134                                     len = strcspn(param,
 135                                                   param[-1] == '"' ? "\"" :" ");
 136                                     av_strlcpy(tmp, param,
 137                                                FFMIN(sizeof(tmp), len+1));
 138                                     param += len;
 139                                     snprintf(stack[sptr].param[PARAM_FACE],
 140                                              sizeof(stack[0].param[PARAM_FACE]),
 141                                              "{\\fn%s}", tmp);
 142                                 }
 143                                 if ((param = strchr(param, ' ')))
 144                                     param++;
 145                             }
 146                             for (i=0; i<PARAM_NUMBER; i++)
 147                                 if (stack[sptr].param[i][0])
 148                                     out += snprintf(out, out_end-out,
 149                                                     stack[sptr].param[i]);
 150                         }
 151                     } else if (!buffer[1] && strspn(buffer, "bisu") == 1) {
 152                         out += snprintf(out, out_end-out,
 153                                         "{\\%c%d}", buffer[0], !tag_close);
 154                     } else {
 155                         unknown = 1;
 156                         snprintf(tmp, sizeof(tmp), "</%s>", buffer);
 157                     }
 158                     if (tag_close) {
 159                         sptr--;
 160                     } else if (unknown && !strstr(in, tmp)) {
 161                         in -= len + tag_close;
 162                         *out++ = *in;
 163                     } else
 164                         av_strlcpy(stack[sptr++].tag, buffer,
 165                                    sizeof(stack[0].tag));
 166                     break;
 167                 }
 168             }
 169         default:
 170             *out++ = *in;
 171             break;
 172         }
 173         if (*in != ' ' && *in != '\r' && *in != '\n')
 174             line_start = 0;
 175     }
 176
 177     out = FFMIN(out, out_end-3);
 178     while (!strncmp(out-2, "\\N", 2))
 179         out -= 2;
 180     while (out[-1] == ' ')
 181         out--;
 182     out += snprintf(out, out_end-out, "\r\n");
 183     return in;
 184 }
 185
 186 static const char *read_ts(const char *buf, int *ts_start, int *ts_end,
 187                            int *x1, int *y1, int *x2, int *y2)
 188 {
 189     int i, hs, ms, ss, he, me, se;
 190
 191     for (i=0; i<2; i++) {
 192         /* try to read timestamps in either the first or second line */
 193         int c = sscanf(buf, "%d:%2d:%2d%*1[,.]%3d --> %d:%2d:%2d%*1[,.]%3d"
 194                        "%*[ ]X1:%u X2:%u Y1:%u Y2:%u",
 195                        &hs, &ms, &ss, ts_start, &he, &me, &se, ts_end,
 196                        x1, x2, y1, y2);
 197         buf += strcspn(buf, "\n") + 1;
 198         if (c >= 8) {
 199             *ts_start = 100*(ss + 60*(ms + 60*hs)) + *ts_start/10;
 200             *ts_end   = 100*(se + 60*(me + 60*he)) + *ts_end  /10;
 201             return buf;
 202         }
 203     }
 204     return NULL;
 205 }
 206
 207 static int srt_decode_frame(AVCodecContext *avctx,
 208                             void *data, int *got_sub_ptr, AVPacket *avpkt)
 209 {
 210     AVSubtitle *sub = data;
 211     int ts_start, ts_end, x1 = -1, y1 = -1, x2 = -1, y2 = -1;
 212     char buffer[2048];
 213     const char *ptr = avpkt->data;
 214     const char *end = avpkt->data + avpkt->size;
 215
 216     if (avpkt->size <= 0)
 217         return avpkt->size;
 218
 219     while (ptr < end && *ptr) {
 220         ptr = read_ts(ptr, &ts_start, &ts_end, &x1, &y1, &x2, &y2);
 221         if (!ptr)
 222             break;
 223         ptr = srt_to_ass(avctx, buffer, buffer+sizeof(buffer), ptr,
 224                          x1, y1, x2, y2);
 225         ff_ass_add_rect(sub, buffer, ts_start, ts_end, 0);
 226     }
 227
 228     *got_sub_ptr = sub->num_rects > 0;
 229     return avpkt->size;
 230 }
 231
 232 AVCodec ff_srt_decoder = {
 233     .name         = "srt",
 234     .long_name    = NULL_IF_CONFIG_SMALL("SubRip subtitle"),
 235     .type         = AVMEDIA_TYPE_SUBTITLE,
 236     .id           = CODEC_ID_SRT,
 237     .init         = ff_ass_subtitle_header_default,
 238     .decode       = srt_decode_frame,
 239 };