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1 | /* |
2 | * Copyright (c) 2012 Clément Bœsch | |
3 | * | |
4 | * This file is part of FFmpeg. | |
5 | * | |
6 | * FFmpeg is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU Lesser General Public | |
8 | * License as published by the Free Software Foundation; either | |
9 | * version 2.1 of the License, or (at your option) any later version. | |
10 | * | |
11 | * FFmpeg is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | * Lesser General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU Lesser General Public | |
17 | * License along with FFmpeg; if not, write to the Free Software | |
18 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
19 | */ | |
20 | ||
21 | /** | |
22 | * @file | |
23 | * WebVTT subtitle demuxer | |
24 | * @see http://dev.w3.org/html5/webvtt/ | |
25 | */ | |
26 | ||
27 | #include "avformat.h" | |
28 | #include "internal.h" | |
29 | #include "subtitles.h" | |
30 | #include "libavutil/bprint.h" | |
31 | #include "libavutil/intreadwrite.h" | |
32 | #include "libavutil/opt.h" | |
33 | ||
34 | typedef struct { | |
35 | const AVClass *class; | |
36 | FFDemuxSubtitlesQueue q; | |
37 | int kind; | |
38 | } WebVTTContext; | |
39 | ||
40 | static int webvtt_probe(AVProbeData *p) | |
41 | { | |
42 | const uint8_t *ptr = p->buf; | |
43 | ||
44 | if (AV_RB24(ptr) == 0xEFBBBF) | |
45 | ptr += 3; /* skip UTF-8 BOM */ | |
46 | if (!strncmp(ptr, "WEBVTT", 6) && | |
47 | (!ptr[6] || strchr("\n\r\t ", ptr[6]))) | |
48 | return AVPROBE_SCORE_MAX; | |
49 | return 0; | |
50 | } | |
51 | ||
52 | static int64_t read_ts(const char *s) | |
53 | { | |
54 | int hh, mm, ss, ms; | |
55 | if (sscanf(s, "%u:%u:%u.%u", &hh, &mm, &ss, &ms) == 4) return (hh*3600LL + mm*60LL + ss) * 1000LL + ms; | |
56 | if (sscanf(s, "%u:%u.%u", &mm, &ss, &ms) == 3) return ( mm*60LL + ss) * 1000LL + ms; | |
57 | return AV_NOPTS_VALUE; | |
58 | } | |
59 | ||
60 | static int webvtt_read_header(AVFormatContext *s) | |
61 | { | |
62 | WebVTTContext *webvtt = s->priv_data; | |
63 | AVBPrint header, cue; | |
64 | int res = 0; | |
65 | AVStream *st = avformat_new_stream(s, NULL); | |
66 | ||
67 | if (!st) | |
68 | return AVERROR(ENOMEM); | |
69 | avpriv_set_pts_info(st, 64, 1, 1000); | |
70 | st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE; | |
71 | st->codec->codec_id = AV_CODEC_ID_WEBVTT; | |
72 | st->disposition |= webvtt->kind; | |
73 | ||
74 | av_bprint_init(&header, 0, AV_BPRINT_SIZE_UNLIMITED); | |
75 | av_bprint_init(&cue, 0, AV_BPRINT_SIZE_UNLIMITED); | |
76 | ||
77 | for (;;) { | |
78 | int i; | |
79 | int64_t pos; | |
80 | AVPacket *sub; | |
81 | const char *p, *identifier, *settings; | |
82 | int identifier_len, settings_len; | |
83 | int64_t ts_start, ts_end; | |
84 | ||
85 | ff_subtitles_read_chunk(s->pb, &cue); | |
86 | ||
87 | if (!cue.len) | |
88 | break; | |
89 | ||
90 | p = identifier = cue.str; | |
91 | pos = avio_tell(s->pb); | |
92 | ||
93 | /* ignore header chunk */ | |
94 | if (!strncmp(p, "\xEF\xBB\xBFWEBVTT", 9) || | |
95 | !strncmp(p, "WEBVTT", 6)) | |
96 | continue; | |
97 | ||
98 | /* optional cue identifier (can be a number like in SRT or some kind of | |
99 | * chaptering id) */ | |
100 | for (i = 0; p[i] && p[i] != '\n' && p[i] != '\r'; i++) { | |
101 | if (!strncmp(p + i, "-->", 3)) { | |
102 | identifier = NULL; | |
103 | break; | |
104 | } | |
105 | } | |
106 | if (!identifier) | |
107 | identifier_len = 0; | |
108 | else { | |
109 | identifier_len = strcspn(p, "\r\n"); | |
110 | p += identifier_len; | |
111 | if (*p == '\r') | |
112 | p++; | |
113 | if (*p == '\n') | |
114 | p++; | |
115 | } | |
116 | ||
117 | /* cue timestamps */ | |
118 | if ((ts_start = read_ts(p)) == AV_NOPTS_VALUE) | |
119 | break; | |
120 | if (!(p = strstr(p, "-->"))) | |
121 | break; | |
122 | p += 2; | |
123 | do p++; while (*p == ' ' || *p == '\t'); | |
124 | if ((ts_end = read_ts(p)) == AV_NOPTS_VALUE) | |
125 | break; | |
126 | ||
127 | /* optional cue settings */ | |
128 | p += strcspn(p, "\n\t "); | |
129 | while (*p == '\t' || *p == ' ') | |
130 | p++; | |
131 | settings = p; | |
132 | settings_len = strcspn(p, "\r\n"); | |
133 | p += settings_len; | |
134 | if (*p == '\r') | |
135 | p++; | |
136 | if (*p == '\n') | |
137 | p++; | |
138 | ||
139 | /* create packet */ | |
140 | sub = ff_subtitles_queue_insert(&webvtt->q, p, strlen(p), 0); | |
141 | if (!sub) { | |
142 | res = AVERROR(ENOMEM); | |
143 | goto end; | |
144 | } | |
145 | sub->pos = pos; | |
146 | sub->pts = ts_start; | |
147 | sub->duration = ts_end - ts_start; | |
148 | ||
149 | #define SET_SIDE_DATA(name, type) do { \ | |
150 | if (name##_len) { \ | |
151 | uint8_t *buf = av_packet_new_side_data(sub, type, name##_len); \ | |
152 | if (!buf) { \ | |
153 | res = AVERROR(ENOMEM); \ | |
154 | goto end; \ | |
155 | } \ | |
156 | memcpy(buf, name, name##_len); \ | |
157 | } \ | |
158 | } while (0) | |
159 | ||
160 | SET_SIDE_DATA(identifier, AV_PKT_DATA_WEBVTT_IDENTIFIER); | |
161 | SET_SIDE_DATA(settings, AV_PKT_DATA_WEBVTT_SETTINGS); | |
162 | } | |
163 | ||
164 | ff_subtitles_queue_finalize(&webvtt->q); | |
165 | ||
166 | end: | |
167 | av_bprint_finalize(&cue, NULL); | |
168 | av_bprint_finalize(&header, NULL); | |
169 | return res; | |
170 | } | |
171 | ||
172 | static int webvtt_read_packet(AVFormatContext *s, AVPacket *pkt) | |
173 | { | |
174 | WebVTTContext *webvtt = s->priv_data; | |
175 | return ff_subtitles_queue_read_packet(&webvtt->q, pkt); | |
176 | } | |
177 | ||
178 | static int webvtt_read_seek(AVFormatContext *s, int stream_index, | |
179 | int64_t min_ts, int64_t ts, int64_t max_ts, int flags) | |
180 | { | |
181 | WebVTTContext *webvtt = s->priv_data; | |
182 | return ff_subtitles_queue_seek(&webvtt->q, s, stream_index, | |
183 | min_ts, ts, max_ts, flags); | |
184 | } | |
185 | ||
186 | static int webvtt_read_close(AVFormatContext *s) | |
187 | { | |
188 | WebVTTContext *webvtt = s->priv_data; | |
189 | ff_subtitles_queue_clean(&webvtt->q); | |
190 | return 0; | |
191 | } | |
192 | ||
193 | #define OFFSET(x) offsetof(WebVTTContext, x) | |
194 | #define KIND_FLAGS AV_OPT_FLAG_SUBTITLE_PARAM | |
195 | ||
196 | static const AVOption options[] = { | |
197 | { "kind", "Set kind of WebVTT track", OFFSET(kind), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, KIND_FLAGS, "webvtt_kind" }, | |
198 | { "subtitles", "WebVTT subtitles kind", 0, AV_OPT_TYPE_CONST, { .i64 = 0 }, INT_MIN, INT_MAX, 0, "webvtt_kind" }, | |
199 | { "captions", "WebVTT captions kind", 0, AV_OPT_TYPE_CONST, { .i64 = AV_DISPOSITION_CAPTIONS }, INT_MIN, INT_MAX, 0, "webvtt_kind" }, | |
200 | { "descriptions", "WebVTT descriptions kind", 0, AV_OPT_TYPE_CONST, { .i64 = AV_DISPOSITION_DESCRIPTIONS }, INT_MIN, INT_MAX, 0, "webvtt_kind" }, | |
201 | { "metadata", "WebVTT metadata kind", 0, AV_OPT_TYPE_CONST, { .i64 = AV_DISPOSITION_METADATA }, INT_MIN, INT_MAX, 0, "webvtt_kind" }, | |
202 | { NULL } | |
203 | }; | |
204 | ||
205 | static const AVClass webvtt_demuxer_class = { | |
206 | .class_name = "WebVTT demuxer", | |
207 | .item_name = av_default_item_name, | |
208 | .option = options, | |
209 | .version = LIBAVUTIL_VERSION_INT, | |
210 | }; | |
211 | ||
212 | AVInputFormat ff_webvtt_demuxer = { | |
213 | .name = "webvtt", | |
214 | .long_name = NULL_IF_CONFIG_SMALL("WebVTT subtitle"), | |
215 | .priv_data_size = sizeof(WebVTTContext), | |
216 | .read_probe = webvtt_probe, | |
217 | .read_header = webvtt_read_header, | |
218 | .read_packet = webvtt_read_packet, | |
219 | .read_seek2 = webvtt_read_seek, | |
220 | .read_close = webvtt_read_close, | |
221 | .extensions = "vtt", | |
222 | .priv_class = &webvtt_demuxer_class, | |
223 | }; |