FFmpeg/libavcodec/webvttdec.c
Andreas Rheinhardt 20f9727018 avcodec/codec_internal: Add FFCodec, hide internal part of AVCodec
Up until now, codec.h contains both public and private parts
of AVCodec. This exposes the internals of AVCodec to users
and leads them into the temptation of actually using them
and forces us to forward-declare structures and types that
users can't use at all.

This commit changes this by adding a new structure FFCodec to
codec_internal.h that extends AVCodec, i.e. contains the public
AVCodec as first member; the private fields of AVCodec are moved
to this structure, leaving codec.h clean.

Reviewed-by: Anton Khirnov <anton@khirnov.net>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2022-03-21 01:33:09 +01:00

113 lines
3.4 KiB
C

/*
* 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
*/
/**
* @file
* WebVTT subtitle decoder
* @see http://dev.w3.org/html5/webvtt/
* @todo need to support extended markups and cue settings
*/
#include "avcodec.h"
#include "ass.h"
#include "codec_internal.h"
#include "libavutil/bprint.h"
static const struct {
const char *from;
const char *to;
} webvtt_tag_replace[] = {
{"<i>", "{\\i1}"}, {"</i>", "{\\i0}"},
{"<b>", "{\\b1}"}, {"</b>", "{\\b0}"},
{"<u>", "{\\u1}"}, {"</u>", "{\\u0}"},
{"{", "\\{"}, {"}", "\\}"}, // escape to avoid ASS markup conflicts
{"&gt;", ">"}, {"&lt;", "<"},
{"&lrm;", ""}, {"&rlm;", ""}, // FIXME: properly honor bidi marks
{"&amp;", "&"}, {"&nbsp;", "\\h"},
};
static int webvtt_event_to_ass(AVBPrint *buf, const char *p)
{
int i, again = 0, skip = 0;
while (*p) {
for (i = 0; i < FF_ARRAY_ELEMS(webvtt_tag_replace); i++) {
const char *from = webvtt_tag_replace[i].from;
const size_t len = strlen(from);
if (!strncmp(p, from, len)) {
av_bprintf(buf, "%s", webvtt_tag_replace[i].to);
p += len;
again = 1;
break;
}
}
if (!*p)
break;
if (again) {
again = 0;
skip = 0;
continue;
}
if (*p == '<')
skip = 1;
else if (*p == '>')
skip = 0;
else if (p[0] == '\n' && p[1])
av_bprintf(buf, "\\N");
else if (!skip && *p != '\r')
av_bprint_chars(buf, *p, 1);
p++;
}
return 0;
}
static int webvtt_decode_frame(AVCodecContext *avctx,
void *data, int *got_sub_ptr, AVPacket *avpkt)
{
int ret = 0;
AVSubtitle *sub = data;
const char *ptr = avpkt->data;
FFASSDecoderContext *s = avctx->priv_data;
AVBPrint buf;
av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
if (ptr && avpkt->size > 0 && !webvtt_event_to_ass(&buf, ptr))
ret = ff_ass_add_rect(sub, buf.str, s->readorder++, 0, NULL, NULL);
av_bprint_finalize(&buf, NULL);
if (ret < 0)
return ret;
*got_sub_ptr = sub->num_rects > 0;
return avpkt->size;
}
const FFCodec ff_webvtt_decoder = {
.p.name = "webvtt",
.p.long_name = NULL_IF_CONFIG_SMALL("WebVTT subtitle"),
.p.type = AVMEDIA_TYPE_SUBTITLE,
.p.id = AV_CODEC_ID_WEBVTT,
.decode = webvtt_decode_frame,
.init = ff_ass_subtitle_header_default,
.flush = ff_ass_decoder_flush,
.priv_data_size = sizeof(FFASSDecoderContext),
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
};