1/* 2 * Copyright (c) 2012 Cl��ment B��sch 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 decoder 24 * @see http://dev.w3.org/html5/webvtt/ 25 * @todo need to support extended markups and cue settings 26 */ 27 28#include "avcodec.h" 29#include "ass.h" 30#include "libavutil/bprint.h" 31 32static const struct { 33 const char *from; 34 const char *to; 35} webvtt_tag_replace[] = { 36 {"<i>", "{\\i1}"}, {"</i>", "{\\i0}"}, 37 {"<b>", "{\\b1}"}, {"</b>", "{\\b0}"}, 38 {"<u>", "{\\u1}"}, {"</u>", "{\\u0}"}, 39 {"{", "\\{"}, {"}", "\\}"}, // escape to avoid ASS markup conflicts 40}; 41 42static int webvtt_event_to_ass(AVBPrint *buf, const char *p) 43{ 44 int i, skip = 0; 45 46 while (*p) { 47 48 for (i = 0; i < FF_ARRAY_ELEMS(webvtt_tag_replace); i++) { 49 const char *from = webvtt_tag_replace[i].from; 50 const size_t len = strlen(from); 51 if (!strncmp(p, from, len)) { 52 av_bprintf(buf, "%s", webvtt_tag_replace[i].to); 53 p += len; 54 break; 55 } 56 } 57 if (!*p) 58 break; 59 60 if (*p == '<') 61 skip = 1; 62 else if (*p == '>') 63 skip = 0; 64 else if (p[0] == '\n' && p[1]) 65 av_bprintf(buf, "\\N"); 66 else if (!skip && *p != '\r') 67 av_bprint_chars(buf, *p, 1); 68 p++; 69 } 70 av_bprintf(buf, "\r\n"); 71 return 0; 72} 73 74static int webvtt_decode_frame(AVCodecContext *avctx, 75 void *data, int *got_sub_ptr, AVPacket *avpkt) 76{ 77 AVSubtitle *sub = data; 78 const char *ptr = avpkt->data; 79 AVBPrint buf; 80 81 av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED); 82 if (ptr && avpkt->size > 0 && !webvtt_event_to_ass(&buf, ptr)) { 83 int ts_start = av_rescale_q(avpkt->pts, avctx->time_base, (AVRational){1,100}); 84 int ts_duration = avpkt->duration != -1 ? 85 av_rescale_q(avpkt->duration, avctx->time_base, (AVRational){1,100}) : -1; 86 ff_ass_add_rect(sub, buf.str, ts_start, ts_duration, 0); 87 } 88 *got_sub_ptr = sub->num_rects > 0; 89 av_bprint_finalize(&buf, NULL); 90 return avpkt->size; 91} 92 93AVCodec ff_webvtt_decoder = { 94 .name = "webvtt", 95 .long_name = NULL_IF_CONFIG_SMALL("WebVTT subtitle"), 96 .type = AVMEDIA_TYPE_SUBTITLE, 97 .id = AV_CODEC_ID_WEBVTT, 98 .decode = webvtt_decode_frame, 99 .init = ff_ass_subtitle_header_default, 100}; 101