/*
* SubRip subtitle demuxer
* Copyright (c) 2010 Aurelien Jacobs <aurel@gnuage.org>
* Copyright (c) 2015 Clément Bœsch <u pkh me>
*
* 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 "avformat.h"
#include "internal.h"
#include "subtitles.h"
#include "libavutil/bprint.h"
#include "libavutil/intreadwrite.h"
typedef struct {
FFDemuxSubtitlesQueue q;
} SRTContext;
static int srt_probe(AVProbeData *p)
{
int v;
char buf[64], *pbuf;
FFTextReader tr;
ff_text_init_buf(&tr, p->buf, p->buf_size);
while (ff_text_peek_r8(&tr) == '\r' || ff_text_peek_r8(&tr) == '\n')
ff_text_r8(&tr);
/* Check if the first non-empty line is a number. We do not check what the
* number is because in practice it can be anything.
* Also, that number can be followed by random garbage, so we can not
* unfortunately check that we only have a number. */
if (ff_subtitles_read_line(&tr, buf, sizeof(buf)) < 0 ||
strtol(buf, &pbuf, 10) < 0 || pbuf == buf)
return 0;
/* Check if the next line matches a SRT timestamp */
if (ff_subtitles_read_line(&tr, buf, sizeof(buf)) < 0)
return 0;
pbuf = buf;
if (buf[0] == '-')
pbuf++;
if (pbuf[0] >= '0' && pbuf[0] <= '9' && strstr(buf, " --> ")
&& sscanf(buf, "%*d:%*d:%*d%*1[,.]%*d --> %*d:%*d:%*d%*1[,.]%d", &v) == 1)
return AVPROBE_SCORE_MAX;
return 0;
}
struct event_info {
int32_t x1, x2, y1, y2;
int duration;
int64_t pts;
int64_t pos;
};
static int get_event_info(const char *line, struct event_info *ei)
{
int hh1, mm1, ss1, ms1;
int hh2, mm2, ss2, ms2;
ei->x1 = ei->x2 = ei->y1 = ei->y2 = ei->duration = -1;
ei->pts = AV_NOPTS_VALUE;
ei->pos = -1;
if (sscanf(line, "%d:%d:%d%*1[,.]%d --> %d:%d:%d%*1[,.]%d"
"%*[ ]X1:%"PRId32" X2:%"PRId32" Y1:%"PRId32" Y2:%"PRId32,
&hh1, &mm1, &ss1, &ms1,
&hh2, &mm2, &ss2, &ms2,
&ei->x1, &ei->x2, &ei->y1, &ei->y2) >= 8) {
const int64_t start = (hh1*3600LL + mm1*60LL + ss1) * 1000LL + ms1;
const int64_t end = (hh2*3600LL + mm2*60LL + ss2) * 1000LL + ms2;
ei->duration = end - start;
ei->pts = start;
return 0;
}
return -1;
}
static int add_event(FFDemuxSubtitlesQueue *q, AVBPrint *buf, char *line_cache,
const struct event_info *ei, int append_cache)
{
if (append_cache && line_cache[0])
av_bprintf(buf, "%s\n", line_cache);
line_cache[0] = 0;
while (buf->len > 0 && buf->str[buf->len - 1] == '\n')
buf->str[--buf->len] = 0;
if (buf->len) {
AVPacket *sub = ff_subtitles_queue_insert(q, buf->str, buf->len, 0);
if (!sub)
return AVERROR(ENOMEM);
av_bprint_clear(buf);
sub->pos = ei->pos;
sub->pts = ei->pts;
sub->duration = ei->duration;
if (ei->x1 != -1) {
uint8_t *p = av_packet_new_side_data(sub, AV_PKT_DATA_SUBTITLE_POSITION, 16);
if (p) {
AV_WL32(p, ei->x1);
AV_WL32(p + 4, ei->y1);
AV_WL32(p + 8, ei->x2);
AV_WL32(p + 12, ei->y2);
}
}
}
return 0;
}
static int srt_read_header(AVFormatContext *s)
{
SRTContext *srt = s->priv_data;
AVBPrint buf;
AVStream *st = avformat_new_stream(s, NULL);
int res = 0;
char line[4096], line_cache[4096];
int has_event_info = 0;
struct event_info ei;
FFTextReader tr;
ff_text_init_avio(s, &tr, s->pb);
if (!st)
return AVERROR(ENOMEM);
avpriv_set_pts_info(st, 64, 1, 1000);
st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;
st->codecpar->codec_id = AV_CODEC_ID_SUBRIP;
av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
line_cache[0] = 0;
while (!ff_text_eof(&tr)) {
struct event_info tmp_ei;
const int64_t pos = ff_text_pos(&tr);
ptrdiff_t len = ff_subtitles_read_line(&tr, line, sizeof(line));
if (len < 0)
break;
if (!len || !line[0])
continue;
if (get_event_info(line, &tmp_ei) < 0) {
char *pline;
if (!has_event_info)
continue;
if (line_cache[0]) {
/* We got some cache and a new line so we assume the cached
* line was actually part of the payload */
av_bprintf(&buf, "%s\n", line_cache);
line_cache[0] = 0;
}
/* If the line doesn't start with a number, we assume it's part of
* the payload, otherwise is likely an event number preceding the
* timing information... but we can't be sure of this yet, so we
* cache it */
if (strtol(line, &pline, 10) < 0 || line == pline)
av_bprintf(&buf, "%s\n", line);
else
strcpy(line_cache, line);
} else {
if (has_event_info) {
/* We have the information of previous event, append it to the
* queue. We insert the cached line if and only if the payload
* is empty and the cached line is not a standalone number. */
char *pline = NULL;
const int standalone_number = strtol(line_cache, &pline, 10) >= 0 && pline && !*pline;
res = add_event(&srt->q, &buf, line_cache, &ei, !buf.len && !standalone_number);
if (res < 0)
goto end;
} else {
has_event_info = 1;
}
tmp_ei.pos = pos;
ei = tmp_ei;
}
}
/* Append the last event. Here we force the cache to be flushed, because a
* trailing number is more likely to be geniune (for example a copyright
* date) and not the event index of an inexistant event */
if (has_event_info) {
res = add_event(&srt->q, &buf, line_cache, &ei, 1);
if (res < 0)
goto end;
}
ff_subtitles_queue_finalize(s, &srt->q);
end:
av_bprint_finalize(&buf, NULL);
return res;
}
static int srt_read_packet(AVFormatContext *s, AVPacket *pkt)
{
SRTContext *srt = s->priv_data;
return ff_subtitles_queue_read_packet(&srt->q, pkt);
}
static int srt_read_seek(AVFormatContext *s, int stream_index,
int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
{
SRTContext *srt = s->priv_data;
return ff_subtitles_queue_seek(&srt->q, s, stream_index,
min_ts, ts, max_ts, flags);
}
static int srt_read_close(AVFormatContext *s)
{
SRTContext *srt = s->priv_data;
ff_subtitles_queue_clean(&srt->q);
return 0;
}
AVInputFormat ff_srt_demuxer = {
.name = "srt",
.long_name = NULL_IF_CONFIG_SMALL("SubRip subtitle"),
.priv_data_size = sizeof(SRTContext),
.read_probe = srt_probe,
.read_header = srt_read_header,
.read_packet = srt_read_packet,
.read_seek2 = srt_read_seek,
.read_close = srt_read_close,
};