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/*
* SSA/ASS demuxer
* Copyright (c) 2008 Michael Niedermayer
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/mathematics.h"
#include "avformat.h"
#include "internal.h"
#define MAX_LINESIZE 2000
typedef struct ASSContext{
uint8_t *event_buffer;
uint8_t **event;
unsigned int event_count;
unsigned int event_index;
}ASSContext;
static int probe(AVProbeData *p)
{
const char *header= "[Script Info]";
if( !memcmp(p->buf , header, strlen(header))
|| !memcmp(p->buf+3, header, strlen(header)))
return AVPROBE_SCORE_MAX;
return 0;
}
static int read_close(AVFormatContext *s)
{
ASSContext *ass = s->priv_data;
av_freep(&ass->event_buffer);
av_freep(&ass->event);
return 0;
}
static int64_t get_pts(const uint8_t *p)
{
int hour, min, sec, hsec;
if(sscanf(p, "%*[^,],%d:%d:%d%*c%d", &hour, &min, &sec, &hsec) != 4)
return AV_NOPTS_VALUE;
// av_log(NULL, AV_LOG_ERROR, "%d %d %d %d %d [%s]\n", i, hour, min, sec, hsec, p);
min+= 60*hour;
sec+= 60*min;
return sec*100+hsec;
}
static int event_cmp(uint8_t **a, uint8_t **b)
{
return get_pts(*a) - get_pts(*b);
}
static int read_header(AVFormatContext *s)
{
int i, len, header_remaining;
ASSContext *ass = s->priv_data;
AVIOContext *pb = s->pb;
AVStream *st;
int allocated[2]={0};
uint8_t *p, **dst[2]={0};
int pos[2]={0};
st = avformat_new_stream(s, NULL);
if (!st)
return -1;
avpriv_set_pts_info(st, 64, 1, 100);
st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
st->codec->codec_id= CODEC_ID_SSA;
header_remaining= INT_MAX;
dst[0] = &st->codec->extradata;
dst[1] = &ass->event_buffer;
while(!pb->eof_reached){
uint8_t line[MAX_LINESIZE];
len = ff_get_line(pb, line, sizeof(line));
if(!memcmp(line, "[Events]", 8))
header_remaining= 2;
else if(line[0]=='[')
header_remaining= INT_MAX;
i= header_remaining==0;
if(i && get_pts(line) == AV_NOPTS_VALUE)
continue;
p = av_fast_realloc(*(dst[i]), &allocated[i], pos[i]+MAX_LINESIZE);
if(!p)
goto fail;
*(dst[i])= p;
memcpy(p + pos[i], line, len+1);
pos[i] += len;
if(i) ass->event_count++;
else header_remaining--;
}
st->codec->extradata_size= pos[0];
if(ass->event_count >= UINT_MAX / sizeof(*ass->event))
goto fail;
ass->event= av_malloc(ass->event_count * sizeof(*ass->event));
p= ass->event_buffer;
for(i=0; i<ass->event_count; i++){
ass->event[i]= p;
while(*p && *p != '\n')
p++;
p++;
}
qsort(ass->event, ass->event_count, sizeof(*ass->event), (void*)event_cmp);
return 0;
fail:
read_close(s);
return -1;
}
static int read_packet(AVFormatContext *s, AVPacket *pkt)
{
ASSContext *ass = s->priv_data;
uint8_t *p, *end;
if(ass->event_index >= ass->event_count)
return AVERROR(EIO);
p= ass->event[ ass->event_index ];
end= strchr(p, '\n');
av_new_packet(pkt, end ? end-p+1 : strlen(p));
pkt->flags |= AV_PKT_FLAG_KEY;
pkt->pos= p - ass->event_buffer + s->streams[0]->codec->extradata_size;
pkt->pts= pkt->dts= get_pts(p);
memcpy(pkt->data, p, pkt->size);
ass->event_index++;
return 0;
}
static int read_seek2(AVFormatContext *s, int stream_index,
int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
{
ASSContext *ass = s->priv_data;
if (flags & AVSEEK_FLAG_BYTE) {
return AVERROR(ENOSYS);
} else if (flags & AVSEEK_FLAG_FRAME) {
if (ts < 0 || ts >= ass->event_count)
return AVERROR(ERANGE);
ass->event_index = ts;
} else {
int i, idx = -1;
int64_t min_ts_diff = INT64_MAX;
if (stream_index == -1) {
AVRational time_base = s->streams[0]->time_base;
ts = av_rescale_q(ts, AV_TIME_BASE_Q, time_base);
min_ts = av_rescale_rnd(min_ts, time_base.den,
time_base.num * (int64_t)AV_TIME_BASE,
AV_ROUND_UP);
max_ts = av_rescale_rnd(max_ts, time_base.den,
time_base.num * (int64_t)AV_TIME_BASE,
AV_ROUND_DOWN);
}
/* TODO: ass->event[] is sorted by pts so we could do a binary search */
for (i=0; i<ass->event_count; i++) {
int64_t pts = get_pts(ass->event[i]);
int64_t ts_diff = FFABS(pts - ts);
if (pts >= min_ts && pts <= max_ts && ts_diff < min_ts_diff) {
min_ts_diff = ts_diff;
idx = i;
}
}
if (idx < 0)
return AVERROR(ERANGE);
ass->event_index = idx;
}
return 0;
}
AVInputFormat ff_ass_demuxer = {
.name = "ass",
.long_name = NULL_IF_CONFIG_SMALL("Advanced SubStation Alpha subtitle format"),
.priv_data_size = sizeof(ASSContext),
.read_probe = probe,
.read_header = read_header,
.read_packet = read_packet,
.read_close = read_close,
.read_seek2 = read_seek2,
};
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