1/* 2 * SSA/ASS demuxer 3 * Copyright (c) 2008 Michael Niedermayer 4 * 5 * This file is part of Libav. 6 * 7 * Libav 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 * Libav 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 Libav; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 20 */ 21 22#include "libavutil/mathematics.h" 23#include "avformat.h" 24#include "internal.h" 25 26#define MAX_LINESIZE 2000 27 28typedef struct ASSContext{ 29 uint8_t *event_buffer; 30 uint8_t **event; 31 unsigned int event_count; 32 unsigned int event_index; 33}ASSContext; 34 35static int probe(AVProbeData *p) 36{ 37 const char *header= "[Script Info]"; 38 39 if( !memcmp(p->buf , header, strlen(header)) 40 || !memcmp(p->buf+3, header, strlen(header))) 41 return AVPROBE_SCORE_MAX; 42 43 return 0; 44} 45 46static int read_close(AVFormatContext *s) 47{ 48 ASSContext *ass = s->priv_data; 49 50 av_freep(&ass->event_buffer); 51 av_freep(&ass->event); 52 53 return 0; 54} 55 56static int64_t get_pts(const uint8_t *p) 57{ 58 int hour, min, sec, hsec; 59 60 if(sscanf(p, "%*[^,],%d:%d:%d%*c%d", &hour, &min, &sec, &hsec) != 4) 61 return AV_NOPTS_VALUE; 62 63// av_log(NULL, AV_LOG_ERROR, "%d %d %d %d %d [%s]\n", i, hour, min, sec, hsec, p); 64 65 min+= 60*hour; 66 sec+= 60*min; 67 68 return sec*100+hsec; 69} 70 71static int event_cmp(uint8_t **a, uint8_t **b) 72{ 73 return get_pts(*a) - get_pts(*b); 74} 75 76static int read_header(AVFormatContext *s, AVFormatParameters *ap) 77{ 78 int i, len, header_remaining; 79 ASSContext *ass = s->priv_data; 80 AVIOContext *pb = s->pb; 81 AVStream *st; 82 int allocated[2]={0}; 83 uint8_t *p, **dst[2]={0}; 84 int pos[2]={0}; 85 86 st = avformat_new_stream(s, NULL); 87 if (!st) 88 return -1; 89 avpriv_set_pts_info(st, 64, 1, 100); 90 st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE; 91 st->codec->codec_id= CODEC_ID_SSA; 92 93 header_remaining= INT_MAX; 94 dst[0] = &st->codec->extradata; 95 dst[1] = &ass->event_buffer; 96 while(!pb->eof_reached){ 97 uint8_t line[MAX_LINESIZE]; 98 99 len = ff_get_line(pb, line, sizeof(line)); 100 101 if(!memcmp(line, "[Events]", 8)) 102 header_remaining= 2; 103 else if(line[0]=='[') 104 header_remaining= INT_MAX; 105 106 i= header_remaining==0; 107 108 if(i && get_pts(line) == AV_NOPTS_VALUE) 109 continue; 110 111 p = av_fast_realloc(*(dst[i]), &allocated[i], pos[i]+MAX_LINESIZE); 112 if(!p) 113 goto fail; 114 *(dst[i])= p; 115 memcpy(p + pos[i], line, len+1); 116 pos[i] += len; 117 if(i) ass->event_count++; 118 else header_remaining--; 119 } 120 st->codec->extradata_size= pos[0]; 121 122 if(ass->event_count >= UINT_MAX / sizeof(*ass->event)) 123 goto fail; 124 125 ass->event= av_malloc(ass->event_count * sizeof(*ass->event)); 126 p= ass->event_buffer; 127 for(i=0; i<ass->event_count; i++){ 128 ass->event[i]= p; 129 while(*p && *p != '\n') 130 p++; 131 p++; 132 } 133 134 qsort(ass->event, ass->event_count, sizeof(*ass->event), (void*)event_cmp); 135 136 return 0; 137 138fail: 139 read_close(s); 140 141 return -1; 142} 143 144static int read_packet(AVFormatContext *s, AVPacket *pkt) 145{ 146 ASSContext *ass = s->priv_data; 147 uint8_t *p, *end; 148 149 if(ass->event_index >= ass->event_count) 150 return AVERROR(EIO); 151 152 p= ass->event[ ass->event_index ]; 153 154 end= strchr(p, '\n'); 155 av_new_packet(pkt, end ? end-p+1 : strlen(p)); 156 pkt->flags |= AV_PKT_FLAG_KEY; 157 pkt->pos= p - ass->event_buffer + s->streams[0]->codec->extradata_size; 158 pkt->pts= pkt->dts= get_pts(p); 159 memcpy(pkt->data, p, pkt->size); 160 161 ass->event_index++; 162 163 return 0; 164} 165 166static int read_seek2(AVFormatContext *s, int stream_index, 167 int64_t min_ts, int64_t ts, int64_t max_ts, int flags) 168{ 169 ASSContext *ass = s->priv_data; 170 171 if (flags & AVSEEK_FLAG_BYTE) { 172 return AVERROR(ENOSYS); 173 } else if (flags & AVSEEK_FLAG_FRAME) { 174 if (ts < 0 || ts >= ass->event_count) 175 return AVERROR(ERANGE); 176 ass->event_index = ts; 177 } else { 178 int i, idx = -1; 179 int64_t min_ts_diff = INT64_MAX; 180 if (stream_index == -1) { 181 AVRational time_base = s->streams[0]->time_base; 182 ts = av_rescale_q(ts, AV_TIME_BASE_Q, time_base); 183 min_ts = av_rescale_rnd(min_ts, time_base.den, 184 time_base.num * (int64_t)AV_TIME_BASE, 185 AV_ROUND_UP); 186 max_ts = av_rescale_rnd(max_ts, time_base.den, 187 time_base.num * (int64_t)AV_TIME_BASE, 188 AV_ROUND_DOWN); 189 } 190 /* TODO: ass->event[] is sorted by pts so we could do a binary search */ 191 for (i=0; i<ass->event_count; i++) { 192 int64_t pts = get_pts(ass->event[i]); 193 int64_t ts_diff = FFABS(pts - ts); 194 if (pts >= min_ts && pts <= max_ts && ts_diff < min_ts_diff) { 195 min_ts_diff = ts_diff; 196 idx = i; 197 } 198 } 199 if (idx < 0) 200 return AVERROR(ERANGE); 201 ass->event_index = idx; 202 } 203 return 0; 204} 205 206AVInputFormat ff_ass_demuxer = { 207 .name = "ass", 208 .long_name = NULL_IF_CONFIG_SMALL("Advanced SubStation Alpha subtitle format"), 209 .priv_data_size = sizeof(ASSContext), 210 .read_probe = probe, 211 .read_header = read_header, 212 .read_packet = read_packet, 213 .read_close = read_close, 214 .read_seek2 = read_seek2, 215}; 216