forked from KolibriOS/kolibrios
249 lines
7.2 KiB
C
249 lines
7.2 KiB
C
/*
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* LRC lyrics file format decoder
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* Copyright (c) 2014 StarBrilliant <m13253@hotmail.com>
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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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#include <inttypes.h>
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#include <stdint.h>
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#include <string.h>
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#include "avformat.h"
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#include "internal.h"
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#include "lrc.h"
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#include "metadata.h"
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#include "subtitles.h"
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#include "libavutil/bprint.h"
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#include "libavutil/dict.h"
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typedef struct LRCContext {
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FFDemuxSubtitlesQueue q;
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int64_t ts_offset; // offset metadata item
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} LRCContext;
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static int64_t find_header(const char *p)
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{
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int64_t offset = 0;
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while(p[offset] == ' ' || p[offset] == '\t') {
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offset++;
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}
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if(p[offset] == '[' && p[offset + 1] >= 'a' && p[offset + 1] <= 'z') {
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return offset;
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} else {
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return -1;
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}
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}
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static int64_t count_ts(const char *p)
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{
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int64_t offset = 0;
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int in_brackets = 0;
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for(;;) {
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if(p[offset] == ' ' || p[offset] == '\t') {
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offset++;
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} else if(p[offset] == '[') {
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offset++;
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in_brackets++;
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} else if (p[offset] == ']' && in_brackets) {
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offset++;
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in_brackets--;
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} else if(in_brackets &&
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(p[offset] == ':' || p[offset] == '.' || p[offset] == '-' ||
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(p[offset] >= '0' && p[offset] <= '9'))) {
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offset++;
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} else {
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break;
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}
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}
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return offset;
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}
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static int64_t read_ts(const char *p, int64_t *start)
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{
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int64_t offset = 0;
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uint64_t mm, ss, cs;
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while(p[offset] == ' ' || p[offset] == '\t') {
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offset++;
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}
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if(p[offset] != '[') {
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return 0;
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}
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if(sscanf(p, "[-%"SCNu64":%"SCNu64".%"SCNu64"]", &mm, &ss, &cs) == 3) {
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/* Just in case negative pts, players may drop it but we won't. */
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*start = -(int64_t) (mm*60000 + ss*1000 + cs*10);
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} else if(sscanf(p, "[%"SCNu64":%"SCNu64".%"SCNu64"]", &mm, &ss, &cs) == 3) {
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*start = mm*60000 + ss*1000 + cs*10;
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} else {
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return 0;
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}
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do {
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offset++;
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} while(p[offset] && p[offset-1] != ']');
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return offset;
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}
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static int64_t read_line(AVBPrint *buf, AVIOContext *pb)
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{
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int64_t pos = avio_tell(pb);
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av_bprint_clear(buf);
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while(!avio_feof(pb)) {
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int c = avio_r8(pb);
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if(c != '\r') {
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av_bprint_chars(buf, c, 1);
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}
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if(c == '\n') {
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break;
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}
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}
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return pos;
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}
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static int lrc_probe(AVProbeData *p)
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{
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int64_t offset = 0;
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int64_t mm;
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uint64_t ss, cs;
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const AVMetadataConv *metadata_item;
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if(!memcmp(p->buf, "\xef\xbb\xbf", 3)) { // Skip UTF-8 BOM header
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offset += 3;
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}
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while(p->buf[offset] == '\n' || p->buf[offset] == '\r') {
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offset++;
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}
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if(p->buf[offset] != '[') {
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return 0;
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}
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offset++;
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// Common metadata item but not exist in ff_lrc_metadata_conv
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if(!memcmp(p->buf + offset, "offset:", 7)) {
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return 40;
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}
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if(sscanf(p->buf + offset, "%"SCNd64":%"SCNu64".%"SCNu64"]",
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&mm, &ss, &cs) == 3) {
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return 50;
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}
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// Metadata items exist in ff_lrc_metadata_conv
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for(metadata_item = ff_lrc_metadata_conv;
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metadata_item->native; metadata_item++) {
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size_t metadata_item_len = strlen(metadata_item->native);
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if(p->buf[offset + metadata_item_len] == ':' &&
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!memcmp(p->buf + offset, metadata_item->native, metadata_item_len)) {
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return 40;
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}
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}
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return 5; // Give it 5 scores since it starts with a bracket
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}
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static int lrc_read_header(AVFormatContext *s)
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{
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LRCContext *lrc = s->priv_data;
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AVBPrint line;
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AVStream *st;
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st = avformat_new_stream(s, NULL);
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if(!st) {
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return AVERROR(ENOMEM);
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}
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avpriv_set_pts_info(st, 64, 1, 1000);
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lrc->ts_offset = 0;
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st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
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st->codec->codec_id = AV_CODEC_ID_TEXT;
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av_bprint_init(&line, 0, AV_BPRINT_SIZE_UNLIMITED);
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while(!avio_feof(s->pb)) {
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int64_t pos = read_line(&line, s->pb);
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int64_t header_offset = find_header(line.str);
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if(header_offset >= 0) {
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char *comma_offset = strchr(line.str, ':');
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if(comma_offset) {
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char *right_bracket_offset = strchr(line.str, ']');
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if(!right_bracket_offset) {
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continue;
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}
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*right_bracket_offset = *comma_offset = '\0';
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if(strcmp(line.str + 1, "offset") ||
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sscanf(comma_offset + 1, "%"SCNd64, &lrc->ts_offset) != 1) {
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av_dict_set(&s->metadata, line.str + 1, comma_offset + 1, 0);
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}
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*comma_offset = ':';
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*right_bracket_offset = ']';
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}
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} else {
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AVPacket *sub;
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int64_t ts_start = AV_NOPTS_VALUE;
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int64_t ts_stroffset = 0;
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int64_t ts_stroffset_incr = 0;
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int64_t ts_strlength = count_ts(line.str);
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while((ts_stroffset_incr = read_ts(line.str + ts_stroffset,
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&ts_start)) != 0) {
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ts_stroffset += ts_stroffset_incr;
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sub = ff_subtitles_queue_insert(&lrc->q, line.str + ts_strlength,
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line.len - ts_strlength, 0);
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if(!sub) {
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return AVERROR(ENOMEM);
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}
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sub->pos = pos;
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sub->pts = ts_start - lrc->ts_offset;
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sub->duration = -1;
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}
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}
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}
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ff_subtitles_queue_finalize(&lrc->q);
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ff_metadata_conv_ctx(s, NULL, ff_lrc_metadata_conv);
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return 0;
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}
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static int lrc_read_packet(AVFormatContext *s, AVPacket *pkt)
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{
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LRCContext *lrc = s->priv_data;
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return ff_subtitles_queue_read_packet(&lrc->q, pkt);
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}
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static int lrc_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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LRCContext *lrc = s->priv_data;
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return ff_subtitles_queue_seek(&lrc->q, s, stream_index,
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min_ts, ts, max_ts, flags);
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}
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static int lrc_read_close(AVFormatContext *s)
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{
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LRCContext *lrc = s->priv_data;
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ff_subtitles_queue_clean(&lrc->q);
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return 0;
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}
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AVInputFormat ff_lrc_demuxer = {
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.name = "lrc",
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.long_name = NULL_IF_CONFIG_SMALL("LRC lyrics"),
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.priv_data_size = sizeof (LRCContext),
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.read_probe = lrc_probe,
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.read_header = lrc_read_header,
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.read_packet = lrc_read_packet,
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.read_close = lrc_read_close,
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.read_seek2 = lrc_read_seek
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};
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