diff options
Diffstat (limited to 'libavformat/webvttdec.c')
| -rw-r--r-- | libavformat/webvttdec.c | 224 |
1 files changed, 224 insertions, 0 deletions
diff --git a/libavformat/webvttdec.c b/libavformat/webvttdec.c new file mode 100644 index 0000000000..47a3255fd0 --- /dev/null +++ b/libavformat/webvttdec.c @@ -0,0 +1,224 @@ +/* + * 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(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 header, 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->codec->codec_type = AVMEDIA_TYPE_SUBTITLE; + st->codec->codec_id = AV_CODEC_ID_WEBVTT; + st->disposition |= webvtt->kind; + + av_bprint_init(&header, 0, AV_BPRINT_SIZE_UNLIMITED); + av_bprint_init(&cue, 0, AV_BPRINT_SIZE_UNLIMITED); + + for (;;) { + int i; + int64_t pos; + AVPacket *sub; + const char *p, *identifier, *settings; + int identifier_len, settings_len; + int64_t ts_start, ts_end; + + ff_subtitles_read_chunk(s->pb, &cue); + + 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\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); + av_bprint_finalize(&header, 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 + +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, 0, "webvtt_kind" }, + { "captions", "WebVTT captions kind", 0, AV_OPT_TYPE_CONST, { .i64 = AV_DISPOSITION_CAPTIONS }, INT_MIN, INT_MAX, 0, "webvtt_kind" }, + { "descriptions", "WebVTT descriptions kind", 0, AV_OPT_TYPE_CONST, { .i64 = AV_DISPOSITION_DESCRIPTIONS }, INT_MIN, INT_MAX, 0, "webvtt_kind" }, + { "metadata", "WebVTT metadata kind", 0, AV_OPT_TYPE_CONST, { .i64 = AV_DISPOSITION_METADATA }, INT_MIN, INT_MAX, 0, "webvtt_kind" }, + { NULL } +}; + +static const AVClass webvtt_demuxer_class = { + .class_name = "WebVTT demuxer", + .item_name = av_default_item_name, + .option = options, + .version = LIBAVUTIL_VERSION_INT, +}; + +AVInputFormat ff_webvtt_demuxer = { + .name = "webvtt", + .long_name = NULL_IF_CONFIG_SMALL("WebVTT subtitle"), + .priv_data_size = sizeof(WebVTTContext), + .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, +}; |