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ffmpeg/libavformat/subtitles.c

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/*
* Copyright (c) 2012-2013 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 "subtitles.h"
#include "avio_internal.h"
#include "libavutil/avassert.h"
#include "libavutil/avstring.h"
void ff_text_init_avio(void *s, FFTextReader *r, AVIOContext *pb)
{
int i;
r->pb = pb;
r->buf_pos = r->buf_len = 0;
r->type = FF_UTF_8;
for (i = 0; i < 2; i++)
r->buf[r->buf_len++] = avio_r8(r->pb);
if (strncmp("\xFF\xFE", r->buf, 2) == 0) {
r->type = FF_UTF16LE;
r->buf_pos += 2;
} else if (strncmp("\xFE\xFF", r->buf, 2) == 0) {
r->type = FF_UTF16BE;
r->buf_pos += 2;
} else {
r->buf[r->buf_len++] = avio_r8(r->pb);
if (strncmp("\xEF\xBB\xBF", r->buf, 3) == 0) {
// UTF8
r->buf_pos += 3;
}
}
if (s && (r->type == FF_UTF16LE || r->type == FF_UTF16BE))
av_log(s, AV_LOG_INFO,
"UTF16 is automatically converted to UTF8, do not specify a character encoding\n");
}
void ff_text_init_buf(FFTextReader *r, void *buf, size_t size)
{
memset(&r->buf_pb, 0, sizeof(r->buf_pb));
ffio_init_context(&r->buf_pb, buf, size, 0, NULL, NULL, NULL, NULL);
ff_text_init_avio(NULL, r, &r->buf_pb);
}
int64_t ff_text_pos(FFTextReader *r)
{
return avio_tell(r->pb) - r->buf_len + r->buf_pos;
}
int ff_text_r8(FFTextReader *r)
{
uint32_t val;
uint8_t tmp;
if (r->buf_pos < r->buf_len)
return r->buf[r->buf_pos++];
if (r->type == FF_UTF16LE) {
GET_UTF16(val, avio_rl16(r->pb), return 0;)
} else if (r->type == FF_UTF16BE) {
GET_UTF16(val, avio_rb16(r->pb), return 0;)
} else {
return avio_r8(r->pb);
}
if (!val)
return 0;
r->buf_pos = 0;
r->buf_len = 0;
PUT_UTF8(val, tmp, r->buf[r->buf_len++] = tmp;)
return r->buf[r->buf_pos++]; // buf_len is at least 1
}
void ff_text_read(FFTextReader *r, char *buf, size_t size)
{
for ( ; size > 0; size--)
*buf++ = ff_text_r8(r);
}
int ff_text_eof(FFTextReader *r)
{
return r->buf_pos >= r->buf_len && avio_feof(r->pb);
}
int ff_text_peek_r8(FFTextReader *r)
{
int c;
if (r->buf_pos < r->buf_len)
return r->buf[r->buf_pos];
c = ff_text_r8(r);
if (!avio_feof(r->pb)) {
r->buf_pos = 0;
r->buf_len = 1;
r->buf[0] = c;
}
return c;
}
AVPacket *ff_subtitles_queue_insert(FFDemuxSubtitlesQueue *q,
const uint8_t *event, size_t 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->flags |= AV_PKT_FLAG_KEY;
sub->pts = sub->dts = 0;
memcpy(sub->data, event, len);
}
return sub;
}
static int cmp_pkt_sub_ts_pos(const void *a, const void *b)
{
const AVPacket *s1 = a;
const AVPacket *s2 = b;
if (s1->pts == s2->pts)
return FFDIFFSIGN(s1->pos, s2->pos);
return FFDIFFSIGN(s1->pts , s2->pts);
}
static int cmp_pkt_sub_pos_ts(const void *a, const void *b)
{
const AVPacket *s1 = a;
const AVPacket *s2 = b;
if (s1->pos == s2->pos) {
if (s1->pts == s2->pts)
return 0;
return s1->pts > s2->pts ? 1 : -1;
}
return s1->pos > s2->pos ? 1 : -1;
}
static void drop_dups(void *log_ctx, FFDemuxSubtitlesQueue *q)
{
int i, drop = 0;
for (i = 1; i < q->nb_subs; i++) {
const int last_id = i - 1 - drop;
const AVPacket *last = &q->subs[last_id];
if (q->subs[i].pts == last->pts &&
q->subs[i].duration == last->duration &&
q->subs[i].stream_index == last->stream_index &&
!strcmp(q->subs[i].data, last->data)) {
av_packet_unref(&q->subs[i]);
drop++;
} else if (drop) {
q->subs[last_id + 1] = q->subs[i];
memset(&q->subs[i], 0, sizeof(q->subs[i])); // for safety
}
}
if (drop) {
q->nb_subs -= drop;
av_log(log_ctx, AV_LOG_WARNING, "Dropping %d duplicated subtitle events\n", drop);
}
}
void ff_subtitles_queue_finalize(void *log_ctx, FFDemuxSubtitlesQueue *q)
{
int i;
qsort(q->subs, q->nb_subs, sizeof(*q->subs),
q->sort == SUB_SORT_TS_POS ? cmp_pkt_sub_ts_pos
: cmp_pkt_sub_pos_ts);
for (i = 0; i < q->nb_subs; i++)
if (q->subs[i].duration < 0 && i < q->nb_subs - 1)
q->subs[i].duration = q->subs[i + 1].pts - q->subs[i].pts;
if (!q->keep_duplicates)
drop_dups(log_ctx, q);
}
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;
if (av_packet_ref(pkt, sub) < 0) {
return AVERROR(ENOMEM);
}
pkt->dts = pkt->pts;
q->current_sub_idx++;
return 0;
}
static int search_sub_ts(const FFDemuxSubtitlesQueue *q, int64_t ts)
{
int s1 = 0, s2 = q->nb_subs - 1;
if (s2 < s1)
return AVERROR(ERANGE);
for (;;) {
int mid;
if (s1 == s2)
return s1;
if (s1 == s2 - 1)
return q->subs[s1].pts <= q->subs[s2].pts ? s1 : s2;
mid = (s1 + s2) / 2;
if (q->subs[mid].pts <= ts)
s1 = mid;
else
s2 = mid;
}
}
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 = search_sub_ts(q, ts);
int64_t ts_selected;
if (idx < 0)
return idx;
for (i = idx; i < q->nb_subs && q->subs[i].pts < min_ts; i++)
if (stream_index == -1 || q->subs[i].stream_index == stream_index)
idx = i;
for (i = idx; i > 0 && q->subs[i].pts > max_ts; i--)
if (stream_index == -1 || q->subs[i].stream_index == stream_index)
idx = i;
ts_selected = q->subs[idx].pts;
if (ts_selected < min_ts || ts_selected > max_ts)
return AVERROR(ERANGE);
/* look back in the latest subtitles for overlapping subtitles */
for (i = idx - 1; i >= 0; i--) {
int64_t pts = q->subs[i].pts;
if (q->subs[i].duration <= 0 ||
(stream_index != -1 && q->subs[i].stream_index != stream_index))
continue;
if (pts >= min_ts && pts > ts_selected - q->subs[i].duration)
idx = i;
else
break;
}
/* If the queue is used to store multiple subtitles streams (like with
* VobSub) and the stream index is not specified, we need to make sure
* to focus on the smallest file position offset for a same timestamp;
* queue is ordered by pts and then filepos, so we can take the first
* entry for a given timestamp. */
if (stream_index == -1)
while (idx > 0 && q->subs[idx - 1].pts == q->subs[idx].pts)
idx--;
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_packet_unref(&q->subs[i]);
av_freep(&q->subs);
q->nb_subs = q->allocated_size = q->current_sub_idx = 0;
}
int ff_smil_extract_next_text_chunk(FFTextReader *tr, AVBPrint *buf, char *c)
{
int i = 0;
char end_chr;
if (!*c) // cached char?
*c = ff_text_r8(tr);
if (!*c)
return 0;
end_chr = *c == '<' ? '>' : '<';
do {
av_bprint_chars(buf, *c, 1);
*c = ff_text_r8(tr);
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 size_t len = strlen(attr);
while (*s) {
while (*s) {
if (!in_quotes && av_isspace(*s))
break;
in_quotes ^= *s == '"'; // XXX: support escaping?
s++;
}
while (av_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_text_chunk(FFTextReader *tr, AVBPrint *buf)
{
char eol_buf[5], last_was_cr = 0;
int n = 0, i = 0, nb_eol = 0;
av_bprint_clear(buf);
for (;;) {
char c = ff_text_r8(tr);
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' || last_was_cr;
if (nb_eol == 2)
break;
eol_buf[i++] = c;
if (i == sizeof(eol_buf) - 1)
break;
last_was_cr = c == '\r';
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++;
}
}
void ff_subtitles_read_chunk(AVIOContext *pb, AVBPrint *buf)
{
FFTextReader tr;
tr.buf_pos = tr.buf_len = 0;
tr.type = 0;
tr.pb = pb;
ff_subtitles_read_text_chunk(&tr, buf);
}
ptrdiff_t ff_subtitles_read_line(FFTextReader *tr, char *buf, size_t size)
{
size_t cur = 0;
if (!size)
return 0;
while (cur + 1 < size) {
unsigned char c = ff_text_r8(tr);
if (!c)
return ff_text_eof(tr) ? cur : AVERROR_INVALIDDATA;
if (c == '\r' || c == '\n')
break;
buf[cur++] = c;
buf[cur] = '\0';
}
if (ff_text_peek_r8(tr) == '\r')
ff_text_r8(tr);
if (ff_text_peek_r8(tr) == '\n')
ff_text_r8(tr);
return cur;
}
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