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mirror of https://github.com/FFmpeg/FFmpeg.git synced 2024-12-07 11:13:41 +02:00
FFmpeg/libavformat/subtitles.c
Andreas Rheinhardt 7001ff74ba avformat/aviobuf: Add ffio_init_(read|write)_context()
Most users of ffio_init_context() simply want to wrap
a buffer into an AVIOContext; they do not provide
function pointers at all.

Therefore this commit adds shortcuts for these two common
operations. This also allows to accept const data when reading
(i.e. the const is now cast away at a central place in
ffio_init_read_context() instead of at several callers).
This also allows to constify the data in ff_text_init_buf().

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2023-09-07 00:41:45 +02:00

467 lines
13 KiB
C

/*
* 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/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, const void *buf, size_t size)
{
ffio_init_read_context(&r->buf_pb, buf, size);
ff_text_init_avio(NULL, r, &r->buf_pb.pub);
}
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 = av_packet_alloc();
if (!sub)
return NULL;
if (av_new_packet(sub, len) < 0) {
av_packet_free(&sub);
return NULL;
}
subs[q->nb_subs++] = sub;
sub->flags |= AV_PKT_FLAG_KEY;
sub->pts = sub->dts = 0;
memcpy(sub->data, event, len);
}
return sub;
}
AVPacket *ff_subtitles_queue_insert_bprint(FFDemuxSubtitlesQueue *q,
const AVBPrint *event, int merge)
{
if (!av_bprint_is_complete(event))
return NULL;
return ff_subtitles_queue_insert(q, event->str, event->len, merge);
}
static int cmp_pkt_sub_ts_pos(const void *a, const void *b)
{
const AVPacket *s1 = *(const AVPacket **)a;
const AVPacket *s2 = *(const AVPacket **)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 = *(const AVPacket **)a;
const AVPacket *s2 = *(const AVPacket **)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_free(&q->subs[i]);
drop++;
} else if (drop) {
q->subs[last_id + 1] = q->subs[i];
q->subs[i] = NULL;
}
}
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;
if (!q->nb_subs)
return;
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 + 1]->pts - (uint64_t)q->subs[i]->pts <= INT64_MAX)
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;
int ret;
if (q->current_sub_idx == q->nb_subs)
return AVERROR_EOF;
sub = q->subs[q->current_sub_idx];
if ((ret = av_packet_ref(pkt, sub)) < 0) {
return ret;
}
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_free(&q->subs[i]);
av_freep(&q->subs);
q->nb_subs = q->allocated_size = q->current_sub_idx = 0;
}
int ff_subtitles_read_packet(AVFormatContext *s, AVPacket *pkt)
{
FFDemuxSubtitlesQueue *q = s->priv_data;
return ff_subtitles_queue_read_packet(q, pkt);
}
int ff_subtitles_read_seek(AVFormatContext *s, int stream_index,
int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
{
FFDemuxSubtitlesQueue *q = s->priv_data;
return ff_subtitles_queue_seek(q, s, stream_index,
min_ts, ts, max_ts, flags);
}
int ff_subtitles_read_close(AVFormatContext *s)
{
FFDemuxSubtitlesQueue *q = s->priv_data;
ff_subtitles_queue_clean(q);
return 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);
if (i == INT_MAX)
return AVERROR_INVALIDDATA;
i++;
} while (*c != end_chr && *c);
if (end_chr == '>') {
av_bprint_chars(buf, '>', 1);
*c = 0;
}
return av_bprint_is_complete(buf) ? i : AVERROR(ENOMEM);
}
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';
}
int 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++;
}
return av_bprint_is_complete(buf) ? 0 : AVERROR(ENOMEM);
}
int ff_subtitles_read_chunk(AVIOContext *pb, AVBPrint *buf)
{
FFTextReader tr;
tr.buf_pos = tr.buf_len = 0;
tr.type = 0;
tr.pb = pb;
return 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;
buf[0] = '\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';
}
while (ff_text_peek_r8(tr) == '\r')
ff_text_r8(tr);
if (ff_text_peek_r8(tr) == '\n')
ff_text_r8(tr);
return cur;
}