/* * Copyright (c) 2012 Clément Bœsch * * 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 */ /** * @file * WebVTT subtitle demuxer * @see http://dev.w3.org/html5/webvtt/ */ #include "avformat.h" #include "internal.h" #include "subtitles.h" #include "libavutil/bprint.h" #include "libavutil/intreadwrite.h" #include "libavutil/opt.h" typedef struct { const AVClass *class; FFDemuxSubtitlesQueue q; int kind; } WebVTTContext; static int webvtt_probe(const AVProbeData *p) { const uint8_t *ptr = p->buf; if (AV_RB24(ptr) == 0xEFBBBF) ptr += 3; /* skip UTF-8 BOM */ if (!strncmp(ptr, "WEBVTT", 6) && (!ptr[6] || strchr("\n\r\t ", ptr[6]))) return AVPROBE_SCORE_MAX; return 0; } static int64_t read_ts(const char *s) { int hh, mm, ss, ms; if (sscanf(s, "%u:%u:%u.%u", &hh, &mm, &ss, &ms) == 4) return (hh*3600LL + mm*60LL + ss) * 1000LL + ms; if (sscanf(s, "%u:%u.%u", &mm, &ss, &ms) == 3) return ( mm*60LL + ss) * 1000LL + ms; return AV_NOPTS_VALUE; } static int webvtt_read_header(AVFormatContext *s) { WebVTTContext *webvtt = s->priv_data; AVBPrint cue; int res = 0; AVStream *st = avformat_new_stream(s, NULL); if (!st) return AVERROR(ENOMEM); avpriv_set_pts_info(st, 64, 1, 1000); st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE; st->codecpar->codec_id = AV_CODEC_ID_WEBVTT; st->disposition |= webvtt->kind; av_bprint_init(&cue, 0, AV_BPRINT_SIZE_UNLIMITED); for (;;) { int i; int64_t pos; AVPacket *sub; const char *p, *identifier, *settings; size_t identifier_len, settings_len; int64_t ts_start, ts_end; res = ff_subtitles_read_chunk(s->pb, &cue); if (res < 0) goto end; if (!cue.len) break; p = identifier = cue.str; pos = avio_tell(s->pb); /* ignore header chunk */ if (!strncmp(p, "\xEF\xBB\xBFWEBVTT", 9) || !strncmp(p, "WEBVTT", 6) || !strncmp(p, "NOTE", 4)) continue; /* optional cue identifier (can be a number like in SRT or some kind of * chaptering id) */ for (i = 0; p[i] && p[i] != '\n' && p[i] != '\r'; i++) { if (!strncmp(p + i, "-->", 3)) { identifier = NULL; break; } } if (!identifier) identifier_len = 0; else { identifier_len = strcspn(p, "\r\n"); p += identifier_len; if (*p == '\r') p++; if (*p == '\n') p++; } /* cue timestamps */ if ((ts_start = read_ts(p)) == AV_NOPTS_VALUE) break; if (!(p = strstr(p, "-->"))) break; p += 2; do p++; while (*p == ' ' || *p == '\t'); if ((ts_end = read_ts(p)) == AV_NOPTS_VALUE) break; /* optional cue settings */ p += strcspn(p, "\n\r\t "); while (*p == '\t' || *p == ' ') p++; settings = p; settings_len = strcspn(p, "\r\n"); p += settings_len; if (*p == '\r') p++; if (*p == '\n') p++; /* create packet */ sub = ff_subtitles_queue_insert(&webvtt->q, p, strlen(p), 0); if (!sub) { res = AVERROR(ENOMEM); goto end; } sub->pos = pos; sub->pts = ts_start; sub->duration = ts_end - ts_start; #define SET_SIDE_DATA(name, type) do { \ if (name##_len) { \ uint8_t *buf = av_packet_new_side_data(sub, type, name##_len); \ if (!buf) { \ res = AVERROR(ENOMEM); \ goto end; \ } \ memcpy(buf, name, name##_len); \ } \ } while (0) SET_SIDE_DATA(identifier, AV_PKT_DATA_WEBVTT_IDENTIFIER); SET_SIDE_DATA(settings, AV_PKT_DATA_WEBVTT_SETTINGS); } ff_subtitles_queue_finalize(s, &webvtt->q); end: av_bprint_finalize(&cue, NULL); return res; } static int webvtt_read_packet(AVFormatContext *s, AVPacket *pkt) { WebVTTContext *webvtt = s->priv_data; return ff_subtitles_queue_read_packet(&webvtt->q, pkt); } static int webvtt_read_seek(AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags) { WebVTTContext *webvtt = s->priv_data; return ff_subtitles_queue_seek(&webvtt->q, s, stream_index, min_ts, ts, max_ts, flags); } static int webvtt_read_close(AVFormatContext *s) { WebVTTContext *webvtt = s->priv_data; ff_subtitles_queue_clean(&webvtt->q); return 0; } #define OFFSET(x) offsetof(WebVTTContext, x) #define KIND_FLAGS AV_OPT_FLAG_SUBTITLE_PARAM|AV_OPT_FLAG_DECODING_PARAM static const AVOption options[] = { { "kind", "Set kind of WebVTT track", OFFSET(kind), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, KIND_FLAGS, "webvtt_kind" }, { "subtitles", "WebVTT subtitles kind", 0, AV_OPT_TYPE_CONST, { .i64 = 0 }, INT_MIN, INT_MAX, KIND_FLAGS, "webvtt_kind" }, { "captions", "WebVTT captions kind", 0, AV_OPT_TYPE_CONST, { .i64 = AV_DISPOSITION_CAPTIONS }, INT_MIN, INT_MAX, KIND_FLAGS, "webvtt_kind" }, { "descriptions", "WebVTT descriptions kind", 0, AV_OPT_TYPE_CONST, { .i64 = AV_DISPOSITION_DESCRIPTIONS }, INT_MIN, INT_MAX, KIND_FLAGS, "webvtt_kind" }, { "metadata", "WebVTT metadata kind", 0, AV_OPT_TYPE_CONST, { .i64 = AV_DISPOSITION_METADATA }, INT_MIN, INT_MAX, KIND_FLAGS, "webvtt_kind" }, { NULL } }; static const AVClass webvtt_demuxer_class = { .class_name = "WebVTT demuxer", .option = options, .version = LIBAVUTIL_VERSION_INT, }; const AVInputFormat ff_webvtt_demuxer = { .name = "webvtt", .long_name = NULL_IF_CONFIG_SMALL("WebVTT subtitle"), .priv_data_size = sizeof(WebVTTContext), .flags_internal = FF_FMT_INIT_CLEANUP, .read_probe = webvtt_probe, .read_header = webvtt_read_header, .read_packet = webvtt_read_packet, .read_seek2 = webvtt_read_seek, .read_close = webvtt_read_close, .extensions = "vtt", .priv_class = &webvtt_demuxer_class, };