225 lines
7.3 KiB
C
225 lines
7.3 KiB
C
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/*
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* Copyright (c) 2012 Clément Bœsch
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* WebVTT subtitle demuxer
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* @see http://dev.w3.org/html5/webvtt/
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*/
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#include "avformat.h"
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#include "internal.h"
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#include "subtitles.h"
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#include "libavutil/bprint.h"
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#include "libavutil/intreadwrite.h"
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#include "libavutil/opt.h"
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typedef struct {
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const AVClass *class;
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FFDemuxSubtitlesQueue q;
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int kind;
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} WebVTTContext;
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static int webvtt_probe(const AVProbeData *p)
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{
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const uint8_t *ptr = p->buf;
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if (AV_RB24(ptr) == 0xEFBBBF)
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ptr += 3; /* skip UTF-8 BOM */
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if (!strncmp(ptr, "WEBVTT", 6) &&
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(!ptr[6] || strchr("\n\r\t ", ptr[6])))
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return AVPROBE_SCORE_MAX;
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return 0;
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}
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static int64_t read_ts(const char *s)
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{
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int hh, mm, ss, ms;
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if (sscanf(s, "%u:%u:%u.%u", &hh, &mm, &ss, &ms) == 4) return (hh*3600LL + mm*60LL + ss) * 1000LL + ms;
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if (sscanf(s, "%u:%u.%u", &mm, &ss, &ms) == 3) return ( mm*60LL + ss) * 1000LL + ms;
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return AV_NOPTS_VALUE;
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}
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static int webvtt_read_header(AVFormatContext *s)
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{
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WebVTTContext *webvtt = s->priv_data;
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AVBPrint cue;
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int res = 0;
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AVStream *st = avformat_new_stream(s, NULL);
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if (!st)
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return AVERROR(ENOMEM);
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avpriv_set_pts_info(st, 64, 1, 1000);
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st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;
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st->codecpar->codec_id = AV_CODEC_ID_WEBVTT;
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st->disposition |= webvtt->kind;
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av_bprint_init(&cue, 0, AV_BPRINT_SIZE_UNLIMITED);
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for (;;) {
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int i;
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int64_t pos;
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AVPacket *sub;
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const char *p, *identifier, *settings;
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int identifier_len, settings_len;
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int64_t ts_start, ts_end;
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ff_subtitles_read_chunk(s->pb, &cue);
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if (!cue.len)
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break;
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p = identifier = cue.str;
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pos = avio_tell(s->pb);
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/* ignore header chunk */
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if (!strncmp(p, "\xEF\xBB\xBFWEBVTT", 9) ||
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!strncmp(p, "WEBVTT", 6) ||
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!strncmp(p, "NOTE", 4))
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continue;
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/* optional cue identifier (can be a number like in SRT or some kind of
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* chaptering id) */
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for (i = 0; p[i] && p[i] != '\n' && p[i] != '\r'; i++) {
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if (!strncmp(p + i, "-->", 3)) {
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identifier = NULL;
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break;
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}
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}
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if (!identifier)
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identifier_len = 0;
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else {
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identifier_len = strcspn(p, "\r\n");
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p += identifier_len;
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if (*p == '\r')
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p++;
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if (*p == '\n')
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p++;
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}
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/* cue timestamps */
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if ((ts_start = read_ts(p)) == AV_NOPTS_VALUE)
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break;
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if (!(p = strstr(p, "-->")))
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break;
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p += 2;
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do p++; while (*p == ' ' || *p == '\t');
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if ((ts_end = read_ts(p)) == AV_NOPTS_VALUE)
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break;
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/* optional cue settings */
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p += strcspn(p, "\n\t ");
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while (*p == '\t' || *p == ' ')
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p++;
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settings = p;
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settings_len = strcspn(p, "\r\n");
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p += settings_len;
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if (*p == '\r')
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p++;
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if (*p == '\n')
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p++;
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/* create packet */
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sub = ff_subtitles_queue_insert(&webvtt->q, p, strlen(p), 0);
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if (!sub) {
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res = AVERROR(ENOMEM);
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goto end;
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}
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sub->pos = pos;
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sub->pts = ts_start;
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sub->duration = ts_end - ts_start;
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#define SET_SIDE_DATA(name, type) do { \
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if (name##_len) { \
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uint8_t *buf = av_packet_new_side_data(sub, type, name##_len); \
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if (!buf) { \
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res = AVERROR(ENOMEM); \
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goto end; \
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} \
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memcpy(buf, name, name##_len); \
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} \
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} while (0)
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SET_SIDE_DATA(identifier, AV_PKT_DATA_WEBVTT_IDENTIFIER);
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SET_SIDE_DATA(settings, AV_PKT_DATA_WEBVTT_SETTINGS);
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}
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ff_subtitles_queue_finalize(s, &webvtt->q);
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end:
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if (res < 0)
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ff_subtitles_queue_clean(&webvtt->q);
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av_bprint_finalize(&cue, NULL);
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return res;
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}
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static int webvtt_read_packet(AVFormatContext *s, AVPacket *pkt)
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{
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WebVTTContext *webvtt = s->priv_data;
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return ff_subtitles_queue_read_packet(&webvtt->q, pkt);
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}
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static int webvtt_read_seek(AVFormatContext *s, int stream_index,
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int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
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{
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WebVTTContext *webvtt = s->priv_data;
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return ff_subtitles_queue_seek(&webvtt->q, s, stream_index,
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min_ts, ts, max_ts, flags);
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}
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static int webvtt_read_close(AVFormatContext *s)
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{
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WebVTTContext *webvtt = s->priv_data;
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ff_subtitles_queue_clean(&webvtt->q);
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return 0;
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}
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#define OFFSET(x) offsetof(WebVTTContext, x)
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#define KIND_FLAGS AV_OPT_FLAG_SUBTITLE_PARAM|AV_OPT_FLAG_DECODING_PARAM
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static const AVOption options[] = {
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{ "kind", "Set kind of WebVTT track", OFFSET(kind), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, KIND_FLAGS, "webvtt_kind" },
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{ "subtitles", "WebVTT subtitles kind", 0, AV_OPT_TYPE_CONST, { .i64 = 0 }, INT_MIN, INT_MAX, KIND_FLAGS, "webvtt_kind" },
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{ "captions", "WebVTT captions kind", 0, AV_OPT_TYPE_CONST, { .i64 = AV_DISPOSITION_CAPTIONS }, INT_MIN, INT_MAX, KIND_FLAGS, "webvtt_kind" },
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{ "descriptions", "WebVTT descriptions kind", 0, AV_OPT_TYPE_CONST, { .i64 = AV_DISPOSITION_DESCRIPTIONS }, INT_MIN, INT_MAX, KIND_FLAGS, "webvtt_kind" },
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{ "metadata", "WebVTT metadata kind", 0, AV_OPT_TYPE_CONST, { .i64 = AV_DISPOSITION_METADATA }, INT_MIN, INT_MAX, KIND_FLAGS, "webvtt_kind" },
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{ NULL }
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};
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static const AVClass webvtt_demuxer_class = {
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.class_name = "WebVTT demuxer",
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.item_name = av_default_item_name,
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.option = options,
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.version = LIBAVUTIL_VERSION_INT,
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};
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AVInputFormat ff_webvtt_demuxer = {
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.name = "webvtt",
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.long_name = NULL_IF_CONFIG_SMALL("WebVTT subtitle"),
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.priv_data_size = sizeof(WebVTTContext),
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.read_probe = webvtt_probe,
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.read_header = webvtt_read_header,
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.read_packet = webvtt_read_packet,
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.read_seek2 = webvtt_read_seek,
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.read_close = webvtt_read_close,
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.extensions = "vtt",
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.priv_class = &webvtt_demuxer_class,
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};
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