/* * 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 };