aac5773f
 hucm
功能基本完成，接口待打磨
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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
*/
/**
* @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 "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
{">", ">"}, {"<", "<"},
{"‎", ""}, {"‏", ""}, // FIXME: properly honor bidi marks
{"&", "&"}, {" ", "\\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;
}
AVCodec ff_webvtt_decoder = {
.name = "webvtt",
.long_name = NULL_IF_CONFIG_SMALL("WebVTT subtitle"),
.type = AVMEDIA_TYPE_SUBTITLE,
.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),
};
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