/* * 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 decoder * @see http://dev.w3.org/html5/webvtt/ * @todo need to support extended markups and cue settings */ #include "avcodec.h" #include "ass.h" #include "libavutil/bprint.h" static const struct { const char *from; const char *to; } webvtt_tag_replace[] = { {"<i>", "{\\i1}"}, {"</i>", "{\\i0}"}, {"<b>", "{\\b1}"}, {"</b>", "{\\b0}"}, {"<u>", "{\\u1}"}, {"</u>", "{\\u0}"}, {"{", "\\{"}, {"}", "\\}"}, // escape to avoid ASS markup conflicts {">", ">"}, {"<", "<"}, {"‎", ""}, {"‏", ""}, // FIXME: properly honor bidi marks {"&", "&"}, {" ", "\\h"}, }; static int webvtt_event_to_ass(AVBPrint *buf, const char *p) { int i, again = 0, skip = 0; while (*p) { for (i = 0; i < FF_ARRAY_ELEMS(webvtt_tag_replace); i++) { const char *from = webvtt_tag_replace[i].from; const size_t len = strlen(from); if (!strncmp(p, from, len)) { av_bprintf(buf, "%s", webvtt_tag_replace[i].to); p += len; again = 1; break; } } if (!*p) break; if (again) { again = 0; skip = 0; continue; } if (*p == '<') skip = 1; else if (*p == '>') skip = 0; else if (p[0] == '\n' && p[1]) av_bprintf(buf, "\\N"); else if (!skip && *p != '\r') av_bprint_chars(buf, *p, 1); p++; } return 0; } static int webvtt_decode_frame(AVCodecContext *avctx, void *data, int *got_sub_ptr, AVPacket *avpkt) { int ret = 0; AVSubtitle *sub = data; const char *ptr = avpkt->data; FFASSDecoderContext *s = avctx->priv_data; AVBPrint buf; av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED); if (ptr && avpkt->size > 0 && !webvtt_event_to_ass(&buf, ptr)) ret = ff_ass_add_rect(sub, buf.str, s->readorder++, 0, NULL, NULL); av_bprint_finalize(&buf, NULL); if (ret < 0) return ret; *got_sub_ptr = sub->num_rects > 0; return avpkt->size; } AVCodec ff_webvtt_decoder = { .name = "webvtt", .long_name = NULL_IF_CONFIG_SMALL("WebVTT subtitle"), .type = AVMEDIA_TYPE_SUBTITLE, .id = AV_CODEC_ID_WEBVTT, .decode = webvtt_decode_frame, .init = ff_ass_subtitle_header_default, .flush = ff_ass_decoder_flush, .priv_data_size = sizeof(FFASSDecoderContext), };