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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 <stdint.h>
#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_TRACE, "%d %d %d %d [%s]\n", hour, min, sec, hsec, p);
min += 60 * hour;
sec += 60 * min;
return sec * 100 + hsec;
}
static int event_cmp(const void *_a, const void *_b)
{
const uint8_t *const *a = _a, *const *b = _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->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;
st->codecpar->codec_id = AV_CODEC_ID_SSA;
header_remaining = INT_MAX;
dst[0] = &st->codecpar->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->codecpar->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), 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;
int ret;
if (ass->event_index >= ass->event_count)
return AVERROR(EIO);
p = ass->event[ass->event_index];
end = strchr(p, '\n');
ret = av_new_packet(pkt, end ? end - p + 1 : strlen(p));
if (ret < 0)
return ret;
pkt->flags |= AV_PKT_FLAG_KEY;
pkt->pos = p - ass->event_buffer + s->streams[0]->codecpar->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("SSA (SubStation Alpha) subtitle"),
.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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