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2ba45a60 DM |
1 | /* |
2 | * LRC lyrics file format decoder | |
3 | * Copyright (c) 2014 StarBrilliant <m13253@hotmail.com> | |
4 | * | |
5 | * This file is part of FFmpeg. | |
6 | * | |
7 | * FFmpeg is free software; you can redistribute it and/or | |
8 | * modify it under the terms of the GNU Lesser General Public | |
9 | * License as published by the Free Software Foundation; either | |
10 | * version 2.1 of the License, or (at your option) any later version. | |
11 | * | |
12 | * FFmpeg is distributed in the hope that it will be useful, | |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
15 | * Lesser General Public License for more details. | |
16 | * | |
17 | * You should have received a copy of the GNU Lesser General Public | |
18 | * License along with FFmpeg; if not, write to the Free Software | |
19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
20 | */ | |
21 | ||
22 | #include <inttypes.h> | |
23 | #include <stdint.h> | |
24 | #include <string.h> | |
25 | ||
26 | #include "avformat.h" | |
27 | #include "internal.h" | |
28 | #include "lrc.h" | |
29 | #include "metadata.h" | |
30 | #include "subtitles.h" | |
31 | #include "libavutil/bprint.h" | |
32 | #include "libavutil/dict.h" | |
33 | ||
34 | typedef struct LRCContext { | |
35 | FFDemuxSubtitlesQueue q; | |
36 | int64_t ts_offset; // offset metadata item | |
37 | } LRCContext; | |
38 | ||
39 | static int64_t find_header(const char *p) | |
40 | { | |
41 | int64_t offset = 0; | |
42 | while(p[offset] == ' ' || p[offset] == '\t') { | |
43 | offset++; | |
44 | } | |
45 | if(p[offset] == '[' && p[offset + 1] >= 'a' && p[offset + 1] <= 'z') { | |
46 | return offset; | |
47 | } else { | |
48 | return -1; | |
49 | } | |
50 | } | |
51 | ||
52 | static int64_t count_ts(const char *p) | |
53 | { | |
54 | int64_t offset = 0; | |
55 | int in_brackets = 0; | |
56 | ||
57 | for(;;) { | |
58 | if(p[offset] == ' ' || p[offset] == '\t') { | |
59 | offset++; | |
60 | } else if(p[offset] == '[') { | |
61 | offset++; | |
62 | in_brackets++; | |
63 | } else if (p[offset] == ']' && in_brackets) { | |
64 | offset++; | |
65 | in_brackets--; | |
66 | } else if(in_brackets && | |
67 | (p[offset] == ':' || p[offset] == '.' || p[offset] == '-' || | |
68 | (p[offset] >= '0' && p[offset] <= '9'))) { | |
69 | offset++; | |
70 | } else { | |
71 | break; | |
72 | } | |
73 | } | |
74 | return offset; | |
75 | } | |
76 | ||
77 | static int64_t read_ts(const char *p, int64_t *start) | |
78 | { | |
79 | int64_t offset = 0; | |
80 | uint64_t mm, ss, cs; | |
81 | ||
82 | while(p[offset] == ' ' || p[offset] == '\t') { | |
83 | offset++; | |
84 | } | |
85 | if(p[offset] != '[') { | |
86 | return 0; | |
87 | } | |
88 | if(sscanf(p, "[-%"SCNu64":%"SCNu64".%"SCNu64"]", &mm, &ss, &cs) == 3) { | |
89 | /* Just in case negative pts, players may drop it but we won't. */ | |
90 | *start = -(int64_t) (mm*60000 + ss*1000 + cs*10); | |
91 | } else if(sscanf(p, "[%"SCNu64":%"SCNu64".%"SCNu64"]", &mm, &ss, &cs) == 3) { | |
92 | *start = mm*60000 + ss*1000 + cs*10; | |
93 | } else { | |
94 | return 0; | |
95 | } | |
96 | do { | |
97 | offset++; | |
98 | } while(p[offset] && p[offset-1] != ']'); | |
99 | return offset; | |
100 | } | |
101 | ||
102 | static int64_t read_line(AVBPrint *buf, AVIOContext *pb) | |
103 | { | |
104 | int64_t pos = avio_tell(pb); | |
105 | ||
106 | av_bprint_clear(buf); | |
107 | while(!avio_feof(pb)) { | |
108 | int c = avio_r8(pb); | |
109 | if(c != '\r') { | |
110 | av_bprint_chars(buf, c, 1); | |
111 | } | |
112 | if(c == '\n') { | |
113 | break; | |
114 | } | |
115 | } | |
116 | return pos; | |
117 | } | |
118 | ||
119 | static int lrc_probe(AVProbeData *p) | |
120 | { | |
121 | int64_t offset = 0; | |
122 | int64_t mm; | |
123 | uint64_t ss, cs; | |
124 | const AVMetadataConv *metadata_item; | |
125 | ||
126 | if(!memcmp(p->buf, "\xef\xbb\xbf", 3)) { // Skip UTF-8 BOM header | |
127 | offset += 3; | |
128 | } | |
129 | while(p->buf[offset] == '\n' || p->buf[offset] == '\r') { | |
130 | offset++; | |
131 | } | |
132 | if(p->buf[offset] != '[') { | |
133 | return 0; | |
134 | } | |
135 | offset++; | |
136 | // Common metadata item but not exist in ff_lrc_metadata_conv | |
137 | if(!memcmp(p->buf + offset, "offset:", 7)) { | |
138 | return 40; | |
139 | } | |
140 | if(sscanf(p->buf + offset, "%"SCNd64":%"SCNu64".%"SCNu64"]", | |
141 | &mm, &ss, &cs) == 3) { | |
142 | return 50; | |
143 | } | |
144 | // Metadata items exist in ff_lrc_metadata_conv | |
145 | for(metadata_item = ff_lrc_metadata_conv; | |
146 | metadata_item->native; metadata_item++) { | |
147 | size_t metadata_item_len = strlen(metadata_item->native); | |
148 | if(p->buf[offset + metadata_item_len] == ':' && | |
149 | !memcmp(p->buf + offset, metadata_item->native, metadata_item_len)) { | |
150 | return 40; | |
151 | } | |
152 | } | |
153 | return 5; // Give it 5 scores since it starts with a bracket | |
154 | } | |
155 | ||
156 | static int lrc_read_header(AVFormatContext *s) | |
157 | { | |
158 | LRCContext *lrc = s->priv_data; | |
159 | AVBPrint line; | |
160 | AVStream *st; | |
161 | ||
162 | st = avformat_new_stream(s, NULL); | |
163 | if(!st) { | |
164 | return AVERROR(ENOMEM); | |
165 | } | |
166 | avpriv_set_pts_info(st, 64, 1, 1000); | |
167 | lrc->ts_offset = 0; | |
168 | st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE; | |
169 | st->codec->codec_id = AV_CODEC_ID_TEXT; | |
170 | av_bprint_init(&line, 0, AV_BPRINT_SIZE_UNLIMITED); | |
171 | ||
172 | while(!avio_feof(s->pb)) { | |
173 | int64_t pos = read_line(&line, s->pb); | |
174 | int64_t header_offset = find_header(line.str); | |
175 | if(header_offset >= 0) { | |
176 | char *comma_offset = strchr(line.str, ':'); | |
177 | if(comma_offset) { | |
178 | char *right_bracket_offset = strchr(line.str, ']'); | |
179 | if(!right_bracket_offset) { | |
180 | continue; | |
181 | } | |
182 | ||
183 | *right_bracket_offset = *comma_offset = '\0'; | |
184 | if(strcmp(line.str + 1, "offset") || | |
185 | sscanf(comma_offset + 1, "%"SCNd64, &lrc->ts_offset) != 1) { | |
186 | av_dict_set(&s->metadata, line.str + 1, comma_offset + 1, 0); | |
187 | } | |
188 | *comma_offset = ':'; | |
189 | *right_bracket_offset = ']'; | |
190 | } | |
191 | ||
192 | } else { | |
193 | AVPacket *sub; | |
194 | int64_t ts_start = AV_NOPTS_VALUE; | |
195 | int64_t ts_stroffset = 0; | |
196 | int64_t ts_stroffset_incr = 0; | |
197 | int64_t ts_strlength = count_ts(line.str); | |
198 | ||
199 | while((ts_stroffset_incr = read_ts(line.str + ts_stroffset, | |
200 | &ts_start)) != 0) { | |
201 | ts_stroffset += ts_stroffset_incr; | |
202 | sub = ff_subtitles_queue_insert(&lrc->q, line.str + ts_strlength, | |
203 | line.len - ts_strlength, 0); | |
204 | if(!sub) { | |
205 | return AVERROR(ENOMEM); | |
206 | } | |
207 | sub->pos = pos; | |
208 | sub->pts = ts_start - lrc->ts_offset; | |
209 | sub->duration = -1; | |
210 | } | |
211 | } | |
212 | } | |
213 | ff_subtitles_queue_finalize(&lrc->q); | |
214 | ff_metadata_conv_ctx(s, NULL, ff_lrc_metadata_conv); | |
215 | return 0; | |
216 | } | |
217 | ||
218 | static int lrc_read_packet(AVFormatContext *s, AVPacket *pkt) | |
219 | { | |
220 | LRCContext *lrc = s->priv_data; | |
221 | return ff_subtitles_queue_read_packet(&lrc->q, pkt); | |
222 | } | |
223 | ||
224 | static int lrc_read_seek(AVFormatContext *s, int stream_index, | |
225 | int64_t min_ts, int64_t ts, int64_t max_ts, int flags) | |
226 | { | |
227 | LRCContext *lrc = s->priv_data; | |
228 | return ff_subtitles_queue_seek(&lrc->q, s, stream_index, | |
229 | min_ts, ts, max_ts, flags); | |
230 | } | |
231 | ||
232 | static int lrc_read_close(AVFormatContext *s) | |
233 | { | |
234 | LRCContext *lrc = s->priv_data; | |
235 | ff_subtitles_queue_clean(&lrc->q); | |
236 | return 0; | |
237 | } | |
238 | ||
239 | AVInputFormat ff_lrc_demuxer = { | |
240 | .name = "lrc", | |
241 | .long_name = NULL_IF_CONFIG_SMALL("LRC lyrics"), | |
242 | .priv_data_size = sizeof (LRCContext), | |
243 | .read_probe = lrc_probe, | |
244 | .read_header = lrc_read_header, | |
245 | .read_packet = lrc_read_packet, | |
246 | .read_close = lrc_read_close, | |
247 | .read_seek2 = lrc_read_seek | |
248 | }; |