libavformat/assenc.c

   1 /*
   2  * SSA/ASS muxer
   3  * Copyright (c) 2008 Michael Niedermayer
   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/mem.h"
  24 #include "avformat.h"
  25 #include "avio_internal.h"
  26 #include "internal.h"
  27 #include "mux.h"
  28
  29 #include "libavutil/opt.h"
  30
  31 typedef struct DialogueLine {
  32     int readorder;
  33     char *line;
  34     struct DialogueLine *prev, *next;
  35 } DialogueLine;
  36
  37 typedef struct ASSContext {
  38     const AVClass *class;
  39     int expected_readorder;
  40     DialogueLine *dialogue_cache;
  41     DialogueLine *last_added_dialogue;
  42     int cache_size;
  43     int ssa_mode;
  44     int ignore_readorder;
  45     uint8_t *trailer;
  46     size_t trailer_size;
  47 } ASSContext;
  48
  49 static int write_header(AVFormatContext *s)
  50 {
  51     ASSContext *ass = s->priv_data;
  52     AVCodecParameters *par = s->streams[0]->codecpar;
  53
  54     avpriv_set_pts_info(s->streams[0], 64, 1, 100);
  55     if (par->extradata_size > 0) {
  56         size_t header_size = par->extradata_size;
  57         uint8_t *trailer = strstr(par->extradata, "\n[Events]");
  58
  59         if (trailer)
  60             trailer = strstr(trailer, "Format:");
  61         if (trailer)
  62             trailer = strstr(trailer, "\n");
  63
  64         if (trailer) {
  65             header_size = (++trailer - par->extradata);
  66             ass->trailer_size = par->extradata_size - header_size;
  67             if (ass->trailer_size)
  68                 ass->trailer = trailer;
  69         }
  70
  71         ffio_write_lines(s->pb, par->extradata, header_size, NULL);
  72
  73         ass->ssa_mode = !strstr(par->extradata, "\n[V4+ Styles]");
  74         if (!strstr(par->extradata, "\n[Events]"))
  75             avio_printf(s->pb, "[Events]\nFormat: %s, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text\n",
  76                         ass->ssa_mode ? "Marked" : "Layer");
  77     }
  78
  79     return 0;
  80 }
  81
  82 static void purge_dialogues(AVFormatContext *s, int force)
  83 {
  84     int n = 0;
  85     ASSContext *ass = s->priv_data;
  86     DialogueLine *dialogue = ass->dialogue_cache;
  87
  88     while (dialogue && (dialogue->readorder == ass->expected_readorder || force)) {
  89         DialogueLine *next = dialogue->next;
  90         if (dialogue->readorder != ass->expected_readorder) {
  91             av_log(s, AV_LOG_WARNING, "ReadOrder gap found between %d and %d\n",
  92                    ass->expected_readorder, dialogue->readorder);
  93             ass->expected_readorder = dialogue->readorder;
  94         }
  95         avio_print(s->pb, "Dialogue: ", dialogue->line, "\n");
  96         if (dialogue == ass->last_added_dialogue)
  97             ass->last_added_dialogue = next;
  98         av_freep(&dialogue->line);
  99         av_free(dialogue);
 100         if (next)
 101             next->prev = NULL;
 102         dialogue = ass->dialogue_cache = next;
 103         ass->expected_readorder++;
 104         n++;
 105     }
 106     ass->cache_size -= n;
 107     if (n > 1)
 108         av_log(s, AV_LOG_DEBUG, "wrote %d ASS lines, cached dialogues: %d, waiting for event id %d\n",
 109                n, ass->cache_size, ass->expected_readorder);
 110 }
 111
 112 static void insert_dialogue(ASSContext *ass, DialogueLine *dialogue)
 113 {
 114     DialogueLine *cur, *next = NULL, *prev = NULL;
 115
 116     /* from the last added to the end of the list */
 117     if (ass->last_added_dialogue) {
 118         for (cur = ass->last_added_dialogue; cur; cur = cur->next) {
 119             if (cur->readorder > dialogue->readorder)
 120                 break;
 121             prev = cur;
 122             next = cur->next;
 123         }
 124     }
 125
 126     /* from the beginning to the last one added */
 127     if (!prev) {
 128         next = ass->dialogue_cache;
 129         for (cur = next; cur != ass->last_added_dialogue; cur = cur->next) {
 130             if (cur->readorder > dialogue->readorder)
 131                 break;
 132             prev = cur;
 133             next = cur->next;
 134         }
 135     }
 136
 137     if (prev) {
 138         prev->next = dialogue;
 139         dialogue->prev = prev;
 140     } else {
 141         dialogue->prev = ass->dialogue_cache;
 142         ass->dialogue_cache = dialogue;
 143     }
 144     if (next) {
 145         next->prev = dialogue;
 146         dialogue->next = next;
 147     }
 148     ass->cache_size++;
 149     ass->last_added_dialogue = dialogue;
 150 }
 151
 152 static int write_packet(AVFormatContext *s, AVPacket *pkt)
 153 {
 154     ASSContext *ass = s->priv_data;
 155
 156     long int layer;
 157     int text_len;
 158     char *p = pkt->data;
 159     int64_t start = pkt->pts;
 160     int64_t end   = start + pkt->duration;
 161     int hh1, mm1, ss1, ms1;
 162     int hh2, mm2, ss2, ms2;
 163     DialogueLine *dialogue = av_mallocz(sizeof(*dialogue));
 164
 165     if (!dialogue)
 166         return AVERROR(ENOMEM);
 167
 168     dialogue->readorder = strtol(p, &p, 10);
 169     if (dialogue->readorder < ass->expected_readorder)
 170         av_log(s, AV_LOG_WARNING, "Unexpected ReadOrder %d\n",
 171                dialogue->readorder);
 172     if (*p == ',')
 173         p++;
 174
 175     if (ass->ssa_mode && !strncmp(p, "Marked=", 7))
 176         p += 7;
 177
 178     layer = strtol(p, &p, 10);
 179     if (*p == ',')
 180         p++;
 181     hh1 = (int)(start / 360000);    mm1 = (int)(start / 6000) % 60;
 182     hh2 = (int)(end   / 360000);    mm2 = (int)(end   / 6000) % 60;
 183     ss1 = (int)(start / 100) % 60;  ms1 = (int)(start % 100);
 184     ss2 = (int)(end   / 100) % 60;  ms2 = (int)(end   % 100);
 185     if (hh1 > 9) hh1 = 9, mm1 = 59, ss1 = 59, ms1 = 99;
 186     if (hh2 > 9) hh2 = 9, mm2 = 59, ss2 = 59, ms2 = 99;
 187
 188     text_len = strlen(p);
 189     while (text_len > 0 && p[text_len - 1] == '\r' || p[text_len - 1] == '\n')
 190         text_len--;
 191
 192     dialogue->line = av_asprintf("%s%ld,%d:%02d:%02d.%02d,%d:%02d:%02d.%02d,%.*s",
 193                                  ass->ssa_mode ? "Marked=" : "",
 194                                  layer, hh1, mm1, ss1, ms1, hh2, mm2, ss2, ms2, text_len, p);
 195     if (!dialogue->line) {
 196         av_free(dialogue);
 197         return AVERROR(ENOMEM);
 198     }
 199     insert_dialogue(ass, dialogue);
 200     purge_dialogues(s, ass->ignore_readorder);
 201
 202     return 0;
 203 }
 204
 205 static int write_trailer(AVFormatContext *s)
 206 {
 207     ASSContext *ass = s->priv_data;
 208
 209     purge_dialogues(s, 1);
 210
 211     if (ass->trailer) {
 212         ffio_write_lines(s->pb, ass->trailer, ass->trailer_size, NULL);
 213     }
 214
 215     return 0;
 216 }
 217
 218 #define OFFSET(x) offsetof(ASSContext, x)
 219 #define E AV_OPT_FLAG_ENCODING_PARAM
 220 static const AVOption options[] = {
 221     { "ignore_readorder", "write events immediately, even if they're out-of-order", OFFSET(ignore_readorder), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, E },
 222     { NULL },
 223 };
 224
 225 static const AVClass ass_class = {
 226     .class_name = "ass muxer",
 227     .item_name  = av_default_item_name,
 228     .option     = options,
 229     .version    = LIBAVUTIL_VERSION_INT,
 230 };
 231
 232 const FFOutputFormat ff_ass_muxer = {
 233     .p.name           = "ass",
 234     .p.long_name      = NULL_IF_CONFIG_SMALL("SSA (SubStation Alpha) subtitle"),
 235     .p.mime_type      = "text/x-ass",
 236     .p.extensions     = "ass,ssa",
 237     .p.audio_codec    = AV_CODEC_ID_NONE,
 238     .p.video_codec    = AV_CODEC_ID_NONE,
 239     .p.subtitle_codec = AV_CODEC_ID_ASS,
 240     .p.flags          = AVFMT_GLOBALHEADER | AVFMT_NOTIMESTAMPS | AVFMT_TS_NONSTRICT,
 241     .flags_internal   = FF_OFMT_FLAG_MAX_ONE_OF_EACH |
 242                         FF_OFMT_FLAG_ONLY_DEFAULT_CODECS,
 243     .p.priv_class     = &ass_class,
 244     .priv_data_size = sizeof(ASSContext),
 245     .write_header   = write_header,
 246     .write_packet   = write_packet,
 247     .write_trailer  = write_trailer,
 248 };