diff options
Diffstat (limited to 'libavformat/lrcdec.c')
| -rw-r--r-- | libavformat/lrcdec.c | 248 |
1 files changed, 248 insertions, 0 deletions
diff --git a/libavformat/lrcdec.c b/libavformat/lrcdec.c new file mode 100644 index 0000000000..df61853d2b --- /dev/null +++ b/libavformat/lrcdec.c @@ -0,0 +1,248 @@ +/* + * 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(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->codec->codec_type = AVMEDIA_TYPE_SUBTITLE; + st->codec->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); + } + *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_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(&lrc->q); + ff_metadata_conv_ctx(s, NULL, ff_lrc_metadata_conv); + return 0; +} + +static int lrc_read_packet(AVFormatContext *s, AVPacket *pkt) +{ + LRCContext *lrc = s->priv_data; + return ff_subtitles_queue_read_packet(&lrc->q, pkt); +} + +static int lrc_read_seek(AVFormatContext *s, int stream_index, + int64_t min_ts, int64_t ts, int64_t max_ts, int flags) +{ + LRCContext *lrc = s->priv_data; + return ff_subtitles_queue_seek(&lrc->q, s, stream_index, + min_ts, ts, max_ts, flags); +} + +static int lrc_read_close(AVFormatContext *s) +{ + LRCContext *lrc = s->priv_data; + ff_subtitles_queue_clean(&lrc->q); + return 0; +} + +AVInputFormat ff_lrc_demuxer = { + .name = "lrc", + .long_name = NULL_IF_CONFIG_SMALL("LRC lyrics"), + .priv_data_size = sizeof (LRCContext), + .read_probe = lrc_probe, + .read_header = lrc_read_header, + .read_packet = lrc_read_packet, + .read_close = lrc_read_close, + .read_seek2 = lrc_read_seek +}; |