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/*
* LRC lyrics file format muxer
* 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 "mux.h"
#include "version.h"
#include "libavutil/dict.h"
#include "libavutil/log.h"
#include "libavutil/macros.h"
#include "libavutil/opt.h"
typedef struct LRCSubtitleContext {
const AVClass *class;
int precision; ///< precision of the fractional part of the timestamp, 2 for centiseconds
} LRCSubtitleContext;
static int lrc_write_header(AVFormatContext *s)
{
const AVDictionaryEntry *metadata_item;
if(s->streams[0]->codecpar->codec_id != AV_CODEC_ID_SUBRIP &&
s->streams[0]->codecpar->codec_id != AV_CODEC_ID_TEXT) {
av_log(s, AV_LOG_ERROR, "Unsupported subtitle codec: %s\n",
avcodec_get_name(s->streams[0]->codecpar->codec_id));
return AVERROR(EINVAL);
}
avpriv_set_pts_info(s->streams[0], 64, 1, AV_TIME_BASE);
ff_standardize_creation_time(s);
ff_metadata_conv_ctx(s, ff_lrc_metadata_conv, NULL);
if(!(s->flags & AVFMT_FLAG_BITEXACT)) { // avoid breaking regression tests
/* LRC provides a metadata slot for specifying encoder version
* in addition to encoder name. We will store LIBAVFORMAT_VERSION
* to it.
*/
av_dict_set(&s->metadata, "ve", AV_STRINGIFY(LIBAVFORMAT_VERSION), 0);
} else {
av_dict_set(&s->metadata, "ve", NULL, 0);
}
for(metadata_item = NULL;
(metadata_item = av_dict_iterate(s->metadata, metadata_item));) {
char *delim;
if(!metadata_item->value[0]) {
continue;
}
while((delim = strchr(metadata_item->value, '\n'))) {
*delim = ' ';
}
while((delim = strchr(metadata_item->value, '\r'))) {
*delim = ' ';
}
avio_printf(s->pb, "[%s:%s]\n",
metadata_item->key, metadata_item->value);
}
avio_w8(s->pb, '\n');
return 0;
}
static int lrc_write_packet(AVFormatContext *s, AVPacket *pkt)
{
const LRCSubtitleContext *p = s->priv_data;
if(pkt->pts != AV_NOPTS_VALUE) {
const uint8_t *line = pkt->data;
const uint8_t *end = pkt->data + pkt->size;
while (end > line && (end[-1] == '\n' || end[-1] == '\r'))
end--;
if (line != end) {
while (line[0] == '\n' || line[0] == '\r')
line++; // Skip first empty lines
}
int frac_mult = 1;
for (int i = 0; i < p->precision; ++i)
frac_mult *= 10;
while(line) {
const uint8_t *next_line = memchr(line, '\n', end - line);
size_t size = end - line;
if (next_line) {
size = next_line - line;
if (next_line > line && next_line[-1] == '\r')
size--;
next_line++;
}
if (size && line[0] == '[') {
av_log(s, AV_LOG_WARNING,
"Subtitle starts with '[', may cause problems with LRC format.\n");
}
/* Offset feature of LRC can easily make pts negative,
* we just output it directly and let the player drop it. */
uint64_t abs_pts = FFABS64U(pkt->pts);
uint64_t minutes = abs_pts / (60 * AV_TIME_BASE);
uint64_t seconds = (abs_pts / AV_TIME_BASE) % 60;
uint64_t fraction = abs_pts % AV_TIME_BASE;
uint64_t rescaled = av_rescale_q(fraction, AV_TIME_BASE_Q, (AVRational){1, frac_mult});
avio_write(s->pb, "[-", 1 + (pkt->pts < 0));
avio_printf(s->pb, "%02"PRIu64":%02"PRIu64".%0*"PRIu64"]",
minutes, seconds, p->precision, rescaled);
avio_write(s->pb, line, size);
avio_w8(s->pb, '\n');
line = next_line;
}
}
return 0;
}
#define OFFSET(x) offsetof(LRCSubtitleContext, x)
#define SE AV_OPT_FLAG_SUBTITLE_PARAM | AV_OPT_FLAG_ENCODING_PARAM
static const AVOption options[] = {
{"precision", "precision of the fractional part of the timestamp, 2 for centiseconds", OFFSET(precision), AV_OPT_TYPE_INT, {.i64 = 2}, 1, 6, SE},
{ NULL },
};
static const AVClass lrcenc_class = {
.class_name = "lrc",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
};
const FFOutputFormat ff_lrc_muxer = {
.p.name = "lrc",
.p.long_name = NULL_IF_CONFIG_SMALL("LRC lyrics"),
.p.extensions = "lrc",
.p.flags = AVFMT_VARIABLE_FPS | AVFMT_GLOBALHEADER |
AVFMT_TS_NEGATIVE | AVFMT_TS_NONSTRICT,
.p.video_codec = AV_CODEC_ID_NONE,
.p.audio_codec = AV_CODEC_ID_NONE,
.p.subtitle_codec = AV_CODEC_ID_SUBRIP,
.flags_internal = FF_OFMT_FLAG_MAX_ONE_OF_EACH,
.priv_data_size = sizeof(LRCSubtitleContext),
.write_header = lrc_write_header,
.write_packet = lrc_write_packet,
.p.priv_class = &lrcenc_class,
};
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