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-rw-r--r--libavformat/lrcdec.c248
1 files changed, 248 insertions, 0 deletions
diff --git a/libavformat/lrcdec.c b/libavformat/lrcdec.c
new file mode 100644
index 0000000000..12f74b22a0
--- /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->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);
+ }
+ *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(s, &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
+};
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