00001 /* 00002 * MicroDVD subtitle demuxer 00003 * Copyright (c) 2010 Aurelien Jacobs <aurel@gnuage.org> 00004 * 00005 * This file is part of FFmpeg. 00006 * 00007 * FFmpeg is free software; you can redistribute it and/or 00008 * modify it under the terms of the GNU Lesser General Public 00009 * License as published by the Free Software Foundation; either 00010 * version 2.1 of the License, or (at your option) any later version. 00011 * 00012 * FFmpeg is distributed in the hope that it will be useful, 00013 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00015 * Lesser General Public License for more details. 00016 * 00017 * You should have received a copy of the GNU Lesser General Public 00018 * License along with FFmpeg; if not, write to the Free Software 00019 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 00020 */ 00021 00022 #include "avformat.h" 00023 #include "internal.h" 00024 #include "libavutil/intreadwrite.h" 00025 00026 #define MAX_LINESIZE 2048 00027 00028 00029 typedef struct { 00030 uint8_t lines[3][MAX_LINESIZE]; 00031 int64_t pos[3]; 00032 } MicroDVDContext; 00033 00034 00035 static int microdvd_probe(AVProbeData *p) 00036 { 00037 unsigned char c, *ptr = p->buf; 00038 int i; 00039 00040 if (AV_RB24(ptr) == 0xEFBBBF) 00041 ptr += 3; /* skip UTF-8 BOM */ 00042 00043 for (i=0; i<3; i++) { 00044 if (sscanf(ptr, "{%*d}{}%c", &c) != 1 && 00045 sscanf(ptr, "{%*d}{%*d}%c", &c) != 1 && 00046 sscanf(ptr, "{DEFAULT}{}%c", &c) != 1) 00047 return 0; 00048 ptr += strcspn(ptr, "\n") + 1; 00049 } 00050 return AVPROBE_SCORE_MAX; 00051 } 00052 00053 static int microdvd_read_header(AVFormatContext *s, AVFormatParameters *ap) 00054 { 00055 AVRational pts_info = (AVRational){ 2997, 125 }; /* default: 23.976 fps */ 00056 MicroDVDContext *microdvd = s->priv_data; 00057 AVStream *st = avformat_new_stream(s, NULL); 00058 int i, frame; 00059 double fps; 00060 char c; 00061 00062 if (!st) 00063 return -1; 00064 for (i=0; i<FF_ARRAY_ELEMS(microdvd->lines); i++) { 00065 microdvd->pos[i] = avio_tell(s->pb); 00066 ff_get_line(s->pb, microdvd->lines[i], sizeof(microdvd->lines[i])); 00067 if ((sscanf(microdvd->lines[i], "{%d}{}%6lf", &frame, &fps) == 2 || 00068 sscanf(microdvd->lines[i], "{%d}{%*d}%6lf", &frame, &fps) == 2) 00069 && frame <= 1 && fps > 3 && fps < 100) 00070 pts_info = av_d2q(fps, 100000); 00071 if (sscanf(microdvd->lines[i], "{DEFAULT}{}%c", &c) == 1) { 00072 st->codec->extradata = av_strdup(microdvd->lines[i] + 11); 00073 st->codec->extradata_size = strlen(st->codec->extradata); 00074 i--; 00075 } 00076 } 00077 avpriv_set_pts_info(st, 64, pts_info.den, pts_info.num); 00078 st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE; 00079 st->codec->codec_id = CODEC_ID_MICRODVD; 00080 return 0; 00081 } 00082 00083 static int64_t get_pts(const char *buf) 00084 { 00085 int frame; 00086 char c; 00087 00088 if (sscanf(buf, "{%d}{%c", &frame, &c) == 2) 00089 return frame; 00090 return AV_NOPTS_VALUE; 00091 } 00092 00093 static int microdvd_read_packet(AVFormatContext *s, AVPacket *pkt) 00094 { 00095 MicroDVDContext *microdvd = s->priv_data; 00096 char buffer[MAX_LINESIZE]; 00097 int64_t pos = avio_tell(s->pb); 00098 int i, len = 0, res = AVERROR_EOF; 00099 00100 for (i=0; i<FF_ARRAY_ELEMS(microdvd->lines); i++) { 00101 if (microdvd->lines[i][0]) { 00102 strcpy(buffer, microdvd->lines[i]); 00103 pos = microdvd->pos[i]; 00104 len = strlen(buffer); 00105 microdvd->lines[i][0] = 0; 00106 break; 00107 } 00108 } 00109 if (!len) 00110 len = ff_get_line(s->pb, buffer, sizeof(buffer)); 00111 00112 if (buffer[0] && !(res = av_new_packet(pkt, len))) { 00113 memcpy(pkt->data, buffer, len); 00114 pkt->flags |= AV_PKT_FLAG_KEY; 00115 pkt->pos = pos; 00116 pkt->pts = pkt->dts = get_pts(buffer); 00117 } 00118 return res; 00119 } 00120 00121 AVInputFormat ff_microdvd_demuxer = { 00122 .name = "microdvd", 00123 .long_name = NULL_IF_CONFIG_SMALL("MicroDVD subtitle format"), 00124 .priv_data_size = sizeof(MicroDVDContext), 00125 .read_probe = microdvd_probe, 00126 .read_header = microdvd_read_header, 00127 .read_packet = microdvd_read_packet, 00128 .flags = AVFMT_GENERIC_INDEX, 00129 };