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/*
* SSA/ASS muxer
* Copyright (c) 2008 Michael Niedermayer
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/avstring.h"
#include "avformat.h"
#include "internal.h"
#include "libavutil/opt.h"
typedef struct DialogueLine {
int readorder;
char *line;
struct DialogueLine *prev, *next;
} DialogueLine;
typedef struct ASSContext {
const AVClass *class;
int write_ts; // 0: ssa (timing in payload), 1: ass (matroska like)
int expected_readorder;
DialogueLine *dialogue_cache;
DialogueLine *last_added_dialogue;
int cache_size;
int ssa_mode;
int ignore_readorder;
uint8_t *trailer;
size_t trailer_size;
} ASSContext;
static int write_header(AVFormatContext *s)
{
ASSContext *ass = s->priv_data;
AVCodecContext *avctx = s->streams[0]->codec;
if (s->nb_streams != 1 || (avctx->codec_id != AV_CODEC_ID_SSA &&
avctx->codec_id != AV_CODEC_ID_ASS)) {
av_log(s, AV_LOG_ERROR, "Exactly one ASS/SSA stream is needed.\n");
return AVERROR(EINVAL);
}
ass->write_ts = avctx->codec_id == AV_CODEC_ID_ASS;
avpriv_set_pts_info(s->streams[0], 64, 1, 100);
if (avctx->extradata_size > 0) {
size_t header_size = avctx->extradata_size;
uint8_t *trailer = strstr(avctx->extradata, "\n[Events]");
if (trailer)
trailer = strstr(trailer, "Format:");
if (trailer)
trailer = strstr(trailer, "\n");
if (trailer++) {
header_size = (trailer - avctx->extradata);
ass->trailer_size = avctx->extradata_size - header_size;
if (ass->trailer_size)
ass->trailer = trailer;
}
avio_write(s->pb, avctx->extradata, header_size);
if (avctx->extradata[header_size - 1] != '\n')
avio_write(s->pb, "\r\n", 2);
ass->ssa_mode = !strstr(avctx->extradata, "\n[V4+ Styles]");
if (!strstr(avctx->extradata, "\n[Events]"))
avio_printf(s->pb, "[Events]\r\nFormat: %s, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text\r\n",
ass->ssa_mode ? "Marked" : "Layer");
}
avio_flush(s->pb);
return 0;
}
static void purge_dialogues(AVFormatContext *s, int force)
{
int n = 0;
ASSContext *ass = s->priv_data;
DialogueLine *dialogue = ass->dialogue_cache;
while (dialogue && (dialogue->readorder == ass->expected_readorder || force)) {
DialogueLine *next = dialogue->next;
if (dialogue->readorder != ass->expected_readorder) {
av_log(s, AV_LOG_WARNING, "ReadOrder gap found between %d and %d\n",
ass->expected_readorder, dialogue->readorder);
ass->expected_readorder = dialogue->readorder;
}
avio_printf(s->pb, "Dialogue: %s\r\n", dialogue->line);
if (dialogue == ass->last_added_dialogue)
ass->last_added_dialogue = next;
av_freep(&dialogue->line);
av_free(dialogue);
if (next)
next->prev = NULL;
dialogue = ass->dialogue_cache = next;
ass->expected_readorder++;
n++;
}
ass->cache_size -= n;
if (n > 1)
av_log(s, AV_LOG_DEBUG, "wrote %d ASS lines, cached dialogues: %d, waiting for event id %d\n",
n, ass->cache_size, ass->expected_readorder);
}
static void insert_dialogue(ASSContext *ass, DialogueLine *dialogue)
{
DialogueLine *cur, *next = NULL, *prev = NULL;
/* from the last added to the end of the list */
if (ass->last_added_dialogue) {
for (cur = ass->last_added_dialogue; cur; cur = cur->next) {
if (cur->readorder > dialogue->readorder)
break;
prev = cur;
next = cur->next;
}
}
/* from the beginning to the last one added */
if (!prev) {
next = ass->dialogue_cache;
for (cur = next; cur != ass->last_added_dialogue; cur = cur->next) {
if (cur->readorder > dialogue->readorder)
break;
prev = cur;
next = cur->next;
}
}
if (prev) {
prev->next = dialogue;
dialogue->prev = prev;
} else {
dialogue->prev = ass->dialogue_cache;
ass->dialogue_cache = dialogue;
}
if (next) {
next->prev = dialogue;
dialogue->next = next;
}
ass->cache_size++;
ass->last_added_dialogue = dialogue;
}
static int write_packet(AVFormatContext *s, AVPacket *pkt)
{
ASSContext *ass = s->priv_data;
if (ass->write_ts) {
long int layer;
char *p = pkt->data;
int64_t start = pkt->pts;
int64_t end = start + pkt->duration;
int hh1, mm1, ss1, ms1;
int hh2, mm2, ss2, ms2;
DialogueLine *dialogue = av_mallocz(sizeof(*dialogue));
if (!dialogue)
return AVERROR(ENOMEM);
dialogue->readorder = strtol(p, &p, 10);
if (dialogue->readorder < ass->expected_readorder)
av_log(s, AV_LOG_WARNING, "Unexpected ReadOrder %d\n",
dialogue->readorder);
if (*p == ',')
p++;
if (ass->ssa_mode && !strncmp(p, "Marked=", 7))
p += 7;
layer = strtol(p, &p, 10);
if (*p == ',')
p++;
hh1 = (int)(start / 360000); mm1 = (int)(start / 6000) % 60;
hh2 = (int)(end / 360000); mm2 = (int)(end / 6000) % 60;
ss1 = (int)(start / 100) % 60; ms1 = (int)(start % 100);
ss2 = (int)(end / 100) % 60; ms2 = (int)(end % 100);
if (hh1 > 9) hh1 = 9, mm1 = 59, ss1 = 59, ms1 = 99;
if (hh2 > 9) hh2 = 9, mm2 = 59, ss2 = 59, ms2 = 99;
dialogue->line = av_asprintf("%s%ld,%d:%02d:%02d.%02d,%d:%02d:%02d.%02d,%s",
ass->ssa_mode ? "Marked=" : "",
layer, hh1, mm1, ss1, ms1, hh2, mm2, ss2, ms2, p);
if (!dialogue->line) {
av_free(dialogue);
return AVERROR(ENOMEM);
}
insert_dialogue(ass, dialogue);
purge_dialogues(s, ass->ignore_readorder);
} else {
avio_write(s->pb, pkt->data, pkt->size);
}
return 0;
}
static int write_trailer(AVFormatContext *s)
{
ASSContext *ass = s->priv_data;
purge_dialogues(s, 1);
if (ass->trailer) {
avio_write(s->pb, ass->trailer, ass->trailer_size);
}
return 0;
}
#define OFFSET(x) offsetof(ASSContext, x)
#define E AV_OPT_FLAG_ENCODING_PARAM
static const AVOption options[] = {
{ "ignore_readorder", "write events immediately, even if they're out-of-order", OFFSET(ignore_readorder), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, E },
{ NULL },
};
static const AVClass ass_class = {
.class_name = "ass muxer",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
};
AVOutputFormat ff_ass_muxer = {
.name = "ass",
.long_name = NULL_IF_CONFIG_SMALL("SSA (SubStation Alpha) subtitle"),
.mime_type = "text/x-ssa",
.extensions = "ass,ssa",
.priv_data_size = sizeof(ASSContext),
.subtitle_codec = AV_CODEC_ID_SSA,
.write_header = write_header,
.write_packet = write_packet,
.write_trailer = write_trailer,
.flags = AVFMT_GLOBALHEADER | AVFMT_NOTIMESTAMPS | AVFMT_TS_NONSTRICT,
.priv_class = &ass_class,
};