ffmpeg/libavformat/subtitles.c

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/*
* Copyright (c) 2012 Clément Bœsch
*
* 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 "subtitles.h"
#include "libavutil/avstring.h"
AVPacket *ff_subtitles_queue_insert(FFDemuxSubtitlesQueue *q,
const uint8_t *event, int len, int merge)
{
AVPacket *subs, *sub;
if (merge && q->nb_subs > 0) {
/* merge with previous event */
int old_len;
sub = &q->subs[q->nb_subs - 1];
old_len = sub->size;
if (av_grow_packet(sub, len) < 0)
return NULL;
memcpy(sub->data + old_len, event, len);
} else {
/* new event */
if (q->nb_subs >= INT_MAX/sizeof(*q->subs) - 1)
return NULL;
subs = av_fast_realloc(q->subs, &q->allocated_size,
(q->nb_subs + 1) * sizeof(*q->subs));
if (!subs)
return NULL;
q->subs = subs;
sub = &subs[q->nb_subs++];
if (av_new_packet(sub, len) < 0)
return NULL;
sub->destruct = NULL;
sub->flags |= AV_PKT_FLAG_KEY;
sub->pts = sub->dts = 0;
memcpy(sub->data, event, len);
}
return sub;
}
static int cmp_pkt_sub(const void *a, const void *b)
{
const AVPacket *s1 = a;
const AVPacket *s2 = b;
if (s1->pts == s2->pts) {
if (s1->pos == s2->pos)
return 0;
return s1->pos > s2->pos ? 1 : -1;
}
return s1->pts > s2->pts ? 1 : -1;
}
void ff_subtitles_queue_finalize(FFDemuxSubtitlesQueue *q)
{
int i;
qsort(q->subs, q->nb_subs, sizeof(*q->subs), cmp_pkt_sub);
for (i = 0; i < q->nb_subs; i++)
if (q->subs[i].duration == -1 && i < q->nb_subs - 1)
q->subs[i].duration = q->subs[i + 1].pts - q->subs[i].pts;
}
int ff_subtitles_queue_read_packet(FFDemuxSubtitlesQueue *q, AVPacket *pkt)
{
AVPacket *sub = q->subs + q->current_sub_idx;
if (q->current_sub_idx == q->nb_subs)
return AVERROR_EOF;
*pkt = *sub;
pkt->dts = pkt->pts;
q->current_sub_idx++;
return 0;
}
int ff_subtitles_queue_seek(FFDemuxSubtitlesQueue *q, AVFormatContext *s, int stream_index,
int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
{
if (flags & AVSEEK_FLAG_BYTE) {
return AVERROR(ENOSYS);
} else if (flags & AVSEEK_FLAG_FRAME) {
if (ts < 0 || ts >= q->nb_subs)
return AVERROR(ERANGE);
q->current_sub_idx = ts;
} else {
int i, idx = -1;
int64_t min_ts_diff = INT64_MAX;
int64_t ts_selected;
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: q->subs[] is sorted by pts so we could do a binary search */
for (i = 0; i < q->nb_subs; i++) {
int64_t pts = q->subs[i].pts;
uint64_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);
/* look back in the latest subtitles for overlapping subtitles */
ts_selected = q->subs[idx].pts;
for (i = idx - 1; i >= 0; i--) {
if (q->subs[i].duration <= 0)
continue;
if (q->subs[i].pts > ts_selected - q->subs[i].duration)
idx = i;
else
break;
}
q->current_sub_idx = idx;
}
return 0;
}
void ff_subtitles_queue_clean(FFDemuxSubtitlesQueue *q)
{
int i;
for (i = 0; i < q->nb_subs; i++)
av_destruct_packet(&q->subs[i]);
av_freep(&q->subs);
q->nb_subs = q->allocated_size = q->current_sub_idx = 0;
}
int ff_smil_extract_next_chunk(AVIOContext *pb, AVBPrint *buf, char *c)
{
int i = 0;
char end_chr;
if (!*c) // cached char?
*c = avio_r8(pb);
if (!*c)
return 0;
end_chr = *c == '<' ? '>' : '<';
do {
av_bprint_chars(buf, *c, 1);
*c = avio_r8(pb);
i++;
} while (*c != end_chr && *c);
if (end_chr == '>') {
av_bprint_chars(buf, '>', 1);
*c = 0;
}
return i;
}
const char *ff_smil_get_attr_ptr(const char *s, const char *attr)
{
int in_quotes = 0;
const int len = strlen(attr);
while (*s) {
while (*s) {
if (!in_quotes && isspace(*s))
break;
in_quotes ^= *s == '"'; // XXX: support escaping?
s++;
}
while (isspace(*s))
s++;
if (!av_strncasecmp(s, attr, len) && s[len] == '=')
return s + len + 1 + (s[len + 1] == '"');
}
return NULL;
}
static inline int is_eol(char c)
{
return c == '\r' || c == '\n';
}
void ff_subtitles_read_chunk(AVIOContext *pb, AVBPrint *buf)
{
char eol_buf[5];
int n = 0, i = 0, nb_eol = 0;
av_bprint_clear(buf);
for (;;) {
char c = avio_r8(pb);
if (!c)
break;
/* ignore all initial line breaks */
if (n == 0 && is_eol(c))
continue;
/* line break buffering: we don't want to add the trailing \r\n */
if (is_eol(c)) {
nb_eol += c == '\n';
if (nb_eol == 2)
break;
eol_buf[i++] = c;
if (i == sizeof(eol_buf) - 1)
break;
continue;
}
/* only one line break followed by data: we flush the line breaks
* buffer */
if (i) {
eol_buf[i] = 0;
av_bprintf(buf, "%s", eol_buf);
i = nb_eol = 0;
}
av_bprint_chars(buf, c, 1);
n++;
}
}