yading@10: /*
yading@10:  * Copyright (c) 2012 Clément Bœsch
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: /**
yading@10:  * @file
yading@10:  * WebVTT subtitle decoder
yading@10:  * @see http://dev.w3.org/html5/webvtt/
yading@10:  * @todo need to support extended markups and cue settings
yading@10:  */
yading@10: 
yading@10: #include "avcodec.h"
yading@10: #include "ass.h"
yading@10: #include "libavutil/bprint.h"
yading@10: 
yading@10: static const struct {
yading@10:     const char *from;
yading@10:     const char *to;
yading@10: } webvtt_tag_replace[] = {
yading@10:     {"<i>", "{\\i1}"}, {"</i>", "{\\i0}"},
yading@10:     {"<b>", "{\\b1}"}, {"</b>", "{\\b0}"},
yading@10:     {"<u>", "{\\u1}"}, {"</u>", "{\\u0}"},
yading@10:     {"{", "\\{"}, {"}", "\\}"}, // escape to avoid ASS markup conflicts
yading@10: };
yading@10: 
yading@10: static int webvtt_event_to_ass(AVBPrint *buf, const char *p)
yading@10: {
yading@10:     int i, skip = 0;
yading@10: 
yading@10:     while (*p) {
yading@10: 
yading@10:         for (i = 0; i < FF_ARRAY_ELEMS(webvtt_tag_replace); i++) {
yading@10:             const char *from = webvtt_tag_replace[i].from;
yading@10:             const size_t len = strlen(from);
yading@10:             if (!strncmp(p, from, len)) {
yading@10:                 av_bprintf(buf, "%s", webvtt_tag_replace[i].to);
yading@10:                 p += len;
yading@10:                 break;
yading@10:             }
yading@10:         }
yading@10:         if (!*p)
yading@10:             break;
yading@10: 
yading@10:         if (*p == '<')
yading@10:             skip = 1;
yading@10:         else if (*p == '>')
yading@10:             skip = 0;
yading@10:         else if (p[0] == '\n' && p[1])
yading@10:             av_bprintf(buf, "\\N");
yading@10:         else if (!skip && *p != '\r')
yading@10:             av_bprint_chars(buf, *p, 1);
yading@10:         p++;
yading@10:     }
yading@10:     av_bprintf(buf, "\r\n");
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int webvtt_decode_frame(AVCodecContext *avctx,
yading@10:                                void *data, int *got_sub_ptr, AVPacket *avpkt)
yading@10: {
yading@10:     AVSubtitle *sub = data;
yading@10:     const char *ptr = avpkt->data;
yading@10:     AVBPrint buf;
yading@10: 
yading@10:     av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
yading@10:     if (ptr && avpkt->size > 0 && !webvtt_event_to_ass(&buf, ptr)) {
yading@10:         int ts_start     = av_rescale_q(avpkt->pts, avctx->time_base, (AVRational){1,100});
yading@10:         int ts_duration  = avpkt->duration != -1 ?
yading@10:                            av_rescale_q(avpkt->duration, avctx->time_base, (AVRational){1,100}) : -1;
yading@10:         ff_ass_add_rect(sub, buf.str, ts_start, ts_duration, 0);
yading@10:     }
yading@10:     *got_sub_ptr = sub->num_rects > 0;
yading@10:     av_bprint_finalize(&buf, NULL);
yading@10:     return avpkt->size;
yading@10: }
yading@10: 
yading@10: AVCodec ff_webvtt_decoder = {
yading@10:     .name           = "webvtt",
yading@10:     .long_name      = NULL_IF_CONFIG_SMALL("WebVTT subtitle"),
yading@10:     .type           = AVMEDIA_TYPE_SUBTITLE,
yading@10:     .id             = AV_CODEC_ID_WEBVTT,
yading@10:     .decode         = webvtt_decode_frame,
yading@10:     .init           = ff_ass_subtitle_header_default,
yading@10: };