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/*
* LRC lyrics file format decoder
* Copyright (c) 2014 StarBrilliant <m13253@hotmail.com>
*
* 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 <inttypes.h>
#include <stdint.h>
#include <string.h>
#include "avformat.h"
#include "internal.h"
#include "lrc.h"
#include "metadata.h"
#include "subtitles.h"
#include "libavutil/bprint.h"
#include "libavutil/dict.h"
typedef struct LRCContext {
FFDemuxSubtitlesQueue q;
int64_t ts_offset; // offset metadata item
} LRCContext;
static int64_t find_header(const char *p)
{
int64_t offset = 0;
while(p[offset] == ' ' || p[offset] == '\t') {
offset++;
}
if(p[offset] == '[' && p[offset + 1] >= 'a' && p[offset + 1] <= 'z') {
return offset;
} else {
return -1;
}
}
static int64_t count_ts(const char *p)
{
int64_t offset = 0;
int in_brackets = 0;
for(;;) {
if(p[offset] == ' ' || p[offset] == '\t') {
offset++;
} else if(p[offset] == '[') {
offset++;
in_brackets++;
} else if (p[offset] == ']' && in_brackets) {
offset++;
in_brackets--;
} else if(in_brackets &&
(p[offset] == ':' || p[offset] == '.' || p[offset] == '-' ||
(p[offset] >= '0' && p[offset] <= '9'))) {
offset++;
} else {
break;
}
}
return offset;
}
static int64_t read_ts(const char *p, int64_t *start)
{
int64_t offset = 0;
uint64_t mm, ss, cs;
while(p[offset] == ' ' || p[offset] == '\t') {
offset++;
}
if(p[offset] != '[') {
return 0;
}
if(sscanf(p, "[-%"SCNu64":%"SCNu64".%"SCNu64"]", &mm, &ss, &cs) == 3) {
/* Just in case negative pts, players may drop it but we won't. */
*start = -(int64_t) (mm*60000 + ss*1000 + cs*10);
} else if(sscanf(p, "[%"SCNu64":%"SCNu64".%"SCNu64"]", &mm, &ss, &cs) == 3) {
*start = mm*60000 + ss*1000 + cs*10;
} else {
return 0;
}
do {
offset++;
} while(p[offset] && p[offset-1] != ']');
return offset;
}
static int64_t read_line(AVBPrint *buf, AVIOContext *pb)
{
int64_t pos = avio_tell(pb);
av_bprint_clear(buf);
while(!avio_feof(pb)) {
int c = avio_r8(pb);
if(c != '\r') {
av_bprint_chars(buf, c, 1);
}
if(c == '\n') {
break;
}
}
return pos;
}
static int lrc_probe(const AVProbeData *p)
{
int64_t offset = 0;
int64_t mm;
uint64_t ss, cs;
const AVMetadataConv *metadata_item;
if(!memcmp(p->buf, "\xef\xbb\xbf", 3)) { // Skip UTF-8 BOM header
offset += 3;
}
while(p->buf[offset] == '\n' || p->buf[offset] == '\r') {
offset++;
}
if(p->buf[offset] != '[') {
return 0;
}
offset++;
// Common metadata item but not exist in ff_lrc_metadata_conv
if(!memcmp(p->buf + offset, "offset:", 7)) {
return 40;
}
if(sscanf(p->buf + offset, "%"SCNd64":%"SCNu64".%"SCNu64"]",
&mm, &ss, &cs) == 3) {
return 50;
}
// Metadata items exist in ff_lrc_metadata_conv
for(metadata_item = ff_lrc_metadata_conv;
metadata_item->native; metadata_item++) {
size_t metadata_item_len = strlen(metadata_item->native);
if(p->buf[offset + metadata_item_len] == ':' &&
!memcmp(p->buf + offset, metadata_item->native, metadata_item_len)) {
return 40;
}
}
return 5; // Give it 5 scores since it starts with a bracket
}
static int lrc_read_header(AVFormatContext *s)
{
LRCContext *lrc = s->priv_data;
AVBPrint line;
AVStream *st;
st = avformat_new_stream(s, NULL);
if(!st) {
return AVERROR(ENOMEM);
}
avpriv_set_pts_info(st, 64, 1, 1000);
lrc->ts_offset = 0;
st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;
st->codecpar->codec_id = AV_CODEC_ID_TEXT;
av_bprint_init(&line, 0, AV_BPRINT_SIZE_UNLIMITED);
while(!avio_feof(s->pb)) {
int64_t pos = read_line(&line, s->pb);
int64_t header_offset = find_header(line.str);
if(header_offset >= 0) {
char *comma_offset = strchr(line.str, ':');
if(comma_offset) {
char *right_bracket_offset = strchr(line.str, ']');
if(!right_bracket_offset) {
continue;
}
*right_bracket_offset = *comma_offset = '\0';
if(strcmp(line.str + 1, "offset") ||
sscanf(comma_offset + 1, "%"SCNd64, &lrc->ts_offset) != 1) {
av_dict_set(&s->metadata, line.str + 1, comma_offset + 1, 0);
}
lrc->ts_offset = av_clip64(lrc->ts_offset, INT64_MIN/4, INT64_MAX/4);
*comma_offset = ':';
*right_bracket_offset = ']';
}
} else {
AVPacket *sub;
int64_t ts_start = AV_NOPTS_VALUE;
int64_t ts_stroffset = 0;
int64_t ts_stroffset_incr = 0;
int64_t ts_strlength = count_ts(line.str);
while((ts_stroffset_incr = read_ts(line.str + ts_stroffset,
&ts_start)) != 0) {
ts_start = av_clip64(ts_start, INT64_MIN/4, INT64_MAX/4);
ts_stroffset += ts_stroffset_incr;
sub = ff_subtitles_queue_insert(&lrc->q, line.str + ts_strlength,
line.len - ts_strlength, 0);
if (!sub)
return AVERROR(ENOMEM);
sub->pos = pos;
sub->pts = ts_start - lrc->ts_offset;
sub->duration = -1;
}
}
}
ff_subtitles_queue_finalize(s, &lrc->q);
ff_metadata_conv_ctx(s, NULL, ff_lrc_metadata_conv);
av_bprint_finalize(&line, NULL);
return 0;
}
const AVInputFormat ff_lrc_demuxer = {
.name = "lrc",
.long_name = NULL_IF_CONFIG_SMALL("LRC lyrics"),
.priv_data_size = sizeof (LRCContext),
.flags_internal = FF_FMT_INIT_CLEANUP,
.read_probe = lrc_probe,
.read_header = lrc_read_header,
.read_packet = ff_subtitles_read_packet,
.read_close = ff_subtitles_read_close,
.read_seek2 = ff_subtitles_read_seek
};
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