1/* 2 * SubRip subtitle muxer 3 * Copyright (c) 2012 Nicolas George <nicolas.george@normalesup.org> 4 * 5 * This file is part of FFmpeg. 6 * 7 * FFmpeg is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU Lesser General Public 9 * License as published by the Free Software Foundation; either 10 * version 2.1 of the License, or (at your option) any later version. 11 * 12 * FFmpeg is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 * Lesser General Public License for more details. 16 * 17 * You should have received a copy of the GNU Lesser General Public 18 * License along with FFmpeg; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 20 */ 21 22#include "avformat.h" 23#include "internal.h" 24#include "libavutil/log.h" 25#include "libavutil/intreadwrite.h" 26 27/* TODO: add options for: 28 - character encoding; 29 - LF / CRLF; 30 - byte order mark. 31 */ 32 33typedef struct SRTContext{ 34 unsigned index; 35} SRTContext; 36 37static int srt_write_header(AVFormatContext *avf) 38{ 39 SRTContext *srt = avf->priv_data; 40 41 if (avf->nb_streams != 1 || 42 avf->streams[0]->codec->codec_type != AVMEDIA_TYPE_SUBTITLE) { 43 av_log(avf, AV_LOG_ERROR, 44 "SRT supports only a single subtitles stream.\n"); 45 return AVERROR(EINVAL); 46 } 47 if (avf->streams[0]->codec->codec_id != AV_CODEC_ID_TEXT && 48 avf->streams[0]->codec->codec_id != AV_CODEC_ID_SUBRIP && 49 avf->streams[0]->codec->codec_id != AV_CODEC_ID_SRT) { 50 av_log(avf, AV_LOG_ERROR, 51 "Unsupported subtitles codec: %s\n", 52 avcodec_get_name(avf->streams[0]->codec->codec_id)); 53 return AVERROR(EINVAL); 54 } 55 avpriv_set_pts_info(avf->streams[0], 64, 1, 1000); 56 srt->index = 1; 57 return 0; 58} 59 60static int srt_write_packet(AVFormatContext *avf, AVPacket *pkt) 61{ 62 SRTContext *srt = avf->priv_data; 63 int write_ts = avf->streams[0]->codec->codec_id != AV_CODEC_ID_SRT; 64 65 if (write_ts) { 66 int64_t s = pkt->pts, e, d = pkt->duration; 67 int size, x1 = -1, y1 = -1, x2 = -1, y2 = -1; 68 const uint8_t *p; 69 70 p = av_packet_get_side_data(pkt, AV_PKT_DATA_SUBTITLE_POSITION, &size); 71 if (p && size == 16) { 72 x1 = AV_RL32(p ); 73 y1 = AV_RL32(p + 4); 74 x2 = AV_RL32(p + 8); 75 y2 = AV_RL32(p + 12); 76 } 77 78 if (d <= 0) 79 /* For backward compatibility, fallback to convergence_duration. */ 80 d = pkt->convergence_duration; 81 if (s == AV_NOPTS_VALUE || d < 0) { 82 av_log(avf, AV_LOG_WARNING, 83 "Insufficient timestamps in event number %d.\n", srt->index); 84 return 0; 85 } 86 e = s + d; 87 avio_printf(avf->pb, "%d\n%02d:%02d:%02d,%03d --> %02d:%02d:%02d,%03d", 88 srt->index, 89 (int)(s / 3600000), (int)(s / 60000) % 60, 90 (int)(s / 1000) % 60, (int)(s % 1000), 91 (int)(e / 3600000), (int)(e / 60000) % 60, 92 (int)(e / 1000) % 60, (int)(e % 1000)); 93 if (p) 94 avio_printf(avf->pb, " X1:%03d X2:%03d Y1:%03d Y2:%03d", 95 x1, x2, y1, y2); 96 avio_printf(avf->pb, "\n"); 97 } 98 avio_write(avf->pb, pkt->data, pkt->size); 99 if (write_ts) 100 avio_write(avf->pb, "\n\n", 2); 101 srt->index++; 102 return 0; 103} 104 105AVOutputFormat ff_srt_muxer = { 106 .name = "srt", 107 .long_name = NULL_IF_CONFIG_SMALL("SubRip subtitle"), 108 .mime_type = "application/x-subrip", 109 .extensions = "srt", 110 .priv_data_size = sizeof(SRTContext), 111 .write_header = srt_write_header, 112 .write_packet = srt_write_packet, 113 .flags = AVFMT_VARIABLE_FPS | AVFMT_TS_NONSTRICT, 114 .subtitle_codec = AV_CODEC_ID_SUBRIP, 115}; 116