libavformat/jacosubdec.c

   1 /*
   2  * Copyright (c) 2012 Clément Bœsch
   3  *
   4  * This file is part of FFmpeg.
   5  *
   6  * FFmpeg is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * FFmpeg is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with FFmpeg; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 /**
  22  * @file
  23  * JACOsub subtitle demuxer
  24  * @see http://unicorn.us.com/jacosub/jscripts.html
  25  * @todo Support P[ALETTE] directive.
  26  */
  27
  28 #include "avformat.h"
  29 #include "internal.h"
  30 #include "subtitles.h"
  31 #include "libavcodec/internal.h"
  32 #include "libavcodec/jacosub.h"
  33 #include "libavutil/avstring.h"
  34 #include "libavutil/bprint.h"
  35 #include "libavutil/intreadwrite.h"
  36
  37 typedef struct {
  38     int shift;
  39     unsigned timeres;
  40     FFDemuxSubtitlesQueue q;
  41 } JACOsubContext;
  42
  43 static int timed_line(const char *ptr)
  44 {
  45     char c;
  46     int fs, fe;
  47     return (sscanf(ptr, "%*u:%*u:%*u.%*u %*u:%*u:%*u.%*u %c", &c) == 1 ||
  48             (sscanf(ptr, "@%u @%u %c", &fs, &fe, &c) == 3 && fs < fe));
  49 }
  50
  51 static int jacosub_probe(const AVProbeData *p)
  52 {
  53     const char *ptr     = p->buf;
  54     const char *ptr_end = p->buf + p->buf_size;
  55
  56     if (AV_RB24(ptr) == 0xEFBBBF)
  57         ptr += 3; /* skip UTF-8 BOM */
  58
  59     while (ptr < ptr_end) {
  60         while (jss_whitespace(*ptr))
  61             ptr++;
  62         if (*ptr != '#' && *ptr != '\n') {
  63             if (timed_line(ptr))
  64                 return AVPROBE_SCORE_EXTENSION + 1;
  65             return 0;
  66         }
  67         ptr += ff_subtitles_next_line(ptr);
  68     }
  69     return 0;
  70 }
  71
  72 static const char * const cmds[] = {
  73     "CLOCKPAUSE",
  74     "DIRECTIVE",
  75     "FONT",
  76     "HRES",
  77     "INCLUDE",
  78     "PALETTE",
  79     "QUANTIZE",
  80     "RAMP",
  81     "SHIFT",
  82     "TIMERES",
  83 };
  84
  85 static int get_jss_cmd(char k)
  86 {
  87     int i;
  88
  89     k = av_toupper(k);
  90     for (i = 0; i < FF_ARRAY_ELEMS(cmds); i++)
  91         if (k == cmds[i][0])
  92             return i;
  93     return -1;
  94 }
  95
  96 static int jacosub_read_close(AVFormatContext *s)
  97 {
  98     JACOsubContext *jacosub = s->priv_data;
  99     ff_subtitles_queue_clean(&jacosub->q);
 100     return 0;
 101 }
 102
 103 static const char *read_ts(JACOsubContext *jacosub, const char *buf,
 104                            int64_t *start, int64_t *duration)
 105 {
 106     int len;
 107     unsigned hs, ms, ss, fs; // hours, minutes, seconds, frame start
 108     unsigned he, me, se, fe; // hours, minutes, seconds, frame end
 109     int ts_start, ts_end;
 110     int64_t ts_start64, ts_end64;
 111
 112     /* timed format */
 113     if (sscanf(buf, "%u:%u:%u.%u %u:%u:%u.%u %n",
 114                &hs, &ms, &ss, &fs,
 115                &he, &me, &se, &fe, &len) == 8) {
 116         ts_start = (hs*3600 + ms*60 + ss) * jacosub->timeres + fs;
 117         ts_end   = (he*3600 + me*60 + se) * jacosub->timeres + fe;
 118         goto shift_and_ret;
 119     }
 120
 121     /* timestamps format */
 122     if (sscanf(buf, "@%u @%u %n", &ts_start, &ts_end, &len) == 2)
 123         goto shift_and_ret;
 124
 125     return NULL;
 126
 127 shift_and_ret:
 128     ts_start64  = (ts_start + (int64_t)jacosub->shift) * 100LL / jacosub->timeres;
 129     ts_end64    = (ts_end   + (int64_t)jacosub->shift) * 100LL / jacosub->timeres;
 130     *start    = ts_start64;
 131     *duration = ts_end64 - ts_start64;
 132     return buf + len;
 133 }
 134
 135 static int get_shift(unsigned timeres, const char *buf)
 136 {
 137     int sign = 1;
 138     int h = 0, m = 0, s = 0, d = 0;
 139     int64_t ret;
 140 #define SSEP "%*1[.:]"
 141     int n = sscanf(buf, "%d"SSEP"%d"SSEP"%d"SSEP"%d", &h, &m, &s, &d);
 142 #undef SSEP
 143
 144     if (h == INT_MIN)
 145         return 0;
 146
 147     if (*buf == '-' || h < 0) {
 148         sign = -1;
 149         h = FFABS(h);
 150     }
 151
 152     ret = 0;
 153     switch (n) {
 154     case 1:        h = 0;                   //clear all in case of a single parameter
 155     case 2: s = m; m = h; h = 0;            //shift into second subsecondd
 156     case 3: d = s; s = m; m = h; h = 0;     //shift into minute second subsecond
 157     }
 158
 159     ret = (int64_t)h*3600 + (int64_t)m*60 + s;
 160     if (FFABS(ret) > (INT64_MAX - FFABS((int64_t)d)) / timeres)
 161         return 0;
 162     ret = sign * (ret * timeres + d);
 163
 164     if ((int)ret != ret)
 165         ret = 0;
 166
 167     return ret;
 168 }
 169
 170 static int jacosub_read_header(AVFormatContext *s)
 171 {
 172     AVBPrint header;
 173     AVIOContext *pb = s->pb;
 174     char line[JSS_MAX_LINESIZE];
 175     JACOsubContext *jacosub = s->priv_data;
 176     int shift_set = 0; // only the first shift matters
 177     int merge_line = 0;
 178     int i, ret;
 179
 180     AVStream *st = avformat_new_stream(s, NULL);
 181     if (!st)
 182         return AVERROR(ENOMEM);
 183     avpriv_set_pts_info(st, 64, 1, 100);
 184     st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;
 185     st->codecpar->codec_id   = AV_CODEC_ID_JACOSUB;
 186
 187     jacosub->timeres = 30;
 188
 189     av_bprint_init(&header, 1024+AV_INPUT_BUFFER_PADDING_SIZE, 4096);
 190
 191     while (!avio_feof(pb)) {
 192         int cmd_len;
 193         const char *p = line;
 194         int64_t pos = avio_tell(pb);
 195         int len = ff_get_line(pb, line, sizeof(line));
 196
 197         p = jss_skip_whitespace(p);
 198
 199         /* queue timed line */
 200         if (merge_line || timed_line(p)) {
 201             AVPacket *sub;
 202
 203             sub = ff_subtitles_queue_insert(&jacosub->q, line, len, merge_line);
 204             if (!sub) {
 205                 ret = AVERROR(ENOMEM);
 206                 goto fail;
 207             }
 208             sub->pos = pos;
 209             merge_line = len > 1 && !strcmp(&line[len - 2], "\\\n");
 210             continue;
 211         }
 212
 213         /* skip all non-compiler commands and focus on the command */
 214         if (*p != '#')
 215             continue;
 216         p++;
 217         i = get_jss_cmd(p[0]);
 218         if (i == -1)
 219             continue;
 220
 221         /* trim command + spaces */
 222         cmd_len = strlen(cmds[i]);
 223         if (av_strncasecmp(p, cmds[i], cmd_len) == 0)
 224             p += cmd_len;
 225         else
 226             p++;
 227         p = jss_skip_whitespace(p);
 228
 229         /* handle commands which affect the whole script */
 230         switch (cmds[i][0]) {
 231         case 'S': // SHIFT command affect the whole script...
 232             if (!shift_set) {
 233                 jacosub->shift = get_shift(jacosub->timeres, p);
 234                 shift_set = 1;
 235             }
 236             av_bprintf(&header, "#S %s", p);
 237             break;
 238         case 'T': { // ...but must be placed after TIMERES
 239             int64_t timeres = strtol(p, NULL, 10);
 240             if (timeres <= 0 || timeres > UINT32_MAX) {
 241                 jacosub->timeres = 30;
 242             } else {
 243                 jacosub->timeres = timeres;
 244                 av_bprintf(&header, "#T %s", p);
 245             }
 246             break;
 247         }
 248         }
 249     }
 250
 251     /* general/essential directives in the extradata */
 252     ret = ff_bprint_to_codecpar_extradata(st->codecpar, &header);
 253     if (ret < 0)
 254         goto fail;
 255
 256     /* SHIFT and TIMERES affect the whole script so packet timing can only be
 257      * done in a second pass */
 258     for (i = 0; i < jacosub->q.nb_subs; i++) {
 259         AVPacket *sub = &jacosub->q.subs[i];
 260         read_ts(jacosub, sub->data, &sub->pts, &sub->duration);
 261     }
 262     ff_subtitles_queue_finalize(s, &jacosub->q);
 263
 264     return 0;
 265 fail:
 266     jacosub_read_close(s);
 267     return ret;
 268 }
 269
 270 static int jacosub_read_packet(AVFormatContext *s, AVPacket *pkt)
 271 {
 272     JACOsubContext *jacosub = s->priv_data;
 273     return ff_subtitles_queue_read_packet(&jacosub->q, pkt);
 274 }
 275
 276 static int jacosub_read_seek(AVFormatContext *s, int stream_index,
 277                              int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
 278 {
 279     JACOsubContext *jacosub = s->priv_data;
 280     return ff_subtitles_queue_seek(&jacosub->q, s, stream_index,
 281                                    min_ts, ts, max_ts, flags);
 282 }
 283
 284 AVInputFormat ff_jacosub_demuxer = {
 285     .name           = "jacosub",
 286     .long_name      = NULL_IF_CONFIG_SMALL("JACOsub subtitle format"),
 287     .priv_data_size = sizeof(JACOsubContext),
 288     .read_probe     = jacosub_probe,
 289     .read_header    = jacosub_read_header,
 290     .read_packet    = jacosub_read_packet,
 291     .read_seek2     = jacosub_read_seek,
 292     .read_close     = jacosub_read_close,
 293 };