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