00001 /* 00002 * DVB subtitle parser for FFmpeg 00003 * Copyright (c) 2005 Ian Caulfield 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 #include "avcodec.h" 00022 #include "dsputil.h" 00023 #include "bitstream.h" 00024 00025 //#define DEBUG 00026 //#define DEBUG_PACKET_CONTENTS 00027 00028 /* Parser (mostly) copied from dvdsub.c */ 00029 00030 #define PARSE_BUF_SIZE (65536) 00031 00032 00033 /* parser definition */ 00034 typedef struct DVBSubParseContext { 00035 uint8_t *packet_buf; 00036 int packet_start; 00037 int packet_index; 00038 int in_packet; 00039 } DVBSubParseContext; 00040 00041 static av_cold int dvbsub_parse_init(AVCodecParserContext *s) 00042 { 00043 DVBSubParseContext *pc = s->priv_data; 00044 pc->packet_buf = av_malloc(PARSE_BUF_SIZE); 00045 00046 return 0; 00047 } 00048 00049 static int dvbsub_parse(AVCodecParserContext *s, 00050 AVCodecContext *avctx, 00051 const uint8_t **poutbuf, int *poutbuf_size, 00052 const uint8_t *buf, int buf_size) 00053 { 00054 DVBSubParseContext *pc = s->priv_data; 00055 uint8_t *p, *p_end; 00056 int len, buf_pos = 0; 00057 00058 #ifdef DEBUG 00059 av_log(avctx, AV_LOG_INFO, "DVB parse packet pts=%"PRIx64", lpts=%"PRIx64", cpts=%"PRIx64":\n", 00060 s->pts, s->last_pts, s->cur_frame_pts[s->cur_frame_start_index]); 00061 #endif 00062 00063 #ifdef DEBUG_PACKET_CONTENTS 00064 int i; 00065 00066 for (i=0; i < buf_size; i++) 00067 { 00068 av_log(avctx, AV_LOG_INFO, "%02x ", buf[i]); 00069 if (i % 16 == 15) 00070 av_log(avctx, AV_LOG_INFO, "\n"); 00071 } 00072 00073 if (i % 16 != 0) 00074 av_log(avctx, AV_LOG_INFO, "\n"); 00075 00076 #endif 00077 00078 *poutbuf = NULL; 00079 *poutbuf_size = 0; 00080 00081 s->fetch_timestamp = 1; 00082 00083 if (s->last_pts != s->pts && s->pts != AV_NOPTS_VALUE) /* Start of a new packet */ 00084 { 00085 if (pc->packet_index != pc->packet_start) 00086 { 00087 #ifdef DEBUG 00088 av_log(avctx, AV_LOG_INFO, "Discarding %d bytes\n", 00089 pc->packet_index - pc->packet_start); 00090 #endif 00091 } 00092 00093 pc->packet_start = 0; 00094 pc->packet_index = 0; 00095 00096 if (buf_size < 2 || buf[0] != 0x20 || buf[1] != 0x00) { 00097 #ifdef DEBUG 00098 av_log(avctx, AV_LOG_INFO, "Bad packet header\n"); 00099 #endif 00100 return -1; 00101 } 00102 00103 buf_pos = 2; 00104 00105 pc->in_packet = 1; 00106 } else { 00107 if (pc->packet_start != 0) 00108 { 00109 if (pc->packet_index != pc->packet_start) 00110 { 00111 memmove(pc->packet_buf, pc->packet_buf + pc->packet_start, 00112 pc->packet_index - pc->packet_start); 00113 00114 pc->packet_index -= pc->packet_start; 00115 pc->packet_start = 0; 00116 } else { 00117 pc->packet_start = 0; 00118 pc->packet_index = 0; 00119 } 00120 } 00121 } 00122 00123 if (buf_size - buf_pos + pc->packet_index > PARSE_BUF_SIZE) 00124 return -1; 00125 00126 /* if not currently in a packet, discard data */ 00127 if (pc->in_packet == 0) 00128 return buf_size; 00129 00130 memcpy(pc->packet_buf + pc->packet_index, buf + buf_pos, buf_size - buf_pos); 00131 pc->packet_index += buf_size - buf_pos; 00132 00133 p = pc->packet_buf; 00134 p_end = pc->packet_buf + pc->packet_index; 00135 00136 while (p < p_end) 00137 { 00138 if (*p == 0x0f) 00139 { 00140 if (p + 6 <= p_end) 00141 { 00142 len = AV_RB16(p + 4); 00143 00144 if (p + len + 6 <= p_end) 00145 { 00146 *poutbuf_size += len + 6; 00147 00148 p += len + 6; 00149 } else 00150 break; 00151 } else 00152 break; 00153 } else if (*p == 0xff) { 00154 if (p + 1 < p_end) 00155 { 00156 #ifdef DEBUG 00157 av_log(avctx, AV_LOG_INFO, "Junk at end of packet\n"); 00158 #endif 00159 } 00160 pc->packet_index = p - pc->packet_buf; 00161 pc->in_packet = 0; 00162 break; 00163 } else { 00164 av_log(avctx, AV_LOG_ERROR, "Junk in packet\n"); 00165 00166 pc->packet_index = p - pc->packet_buf; 00167 pc->in_packet = 0; 00168 break; 00169 } 00170 } 00171 00172 if (*poutbuf_size > 0) 00173 { 00174 *poutbuf = pc->packet_buf; 00175 pc->packet_start = *poutbuf_size; 00176 } 00177 00178 if (s->pts == AV_NOPTS_VALUE) 00179 s->pts = s->last_pts; 00180 00181 return buf_size; 00182 } 00183 00184 static av_cold void dvbsub_parse_close(AVCodecParserContext *s) 00185 { 00186 DVBSubParseContext *pc = s->priv_data; 00187 av_freep(&pc->packet_buf); 00188 } 00189 00190 AVCodecParser dvbsub_parser = { 00191 { CODEC_ID_DVB_SUBTITLE }, 00192 sizeof(DVBSubParseContext), 00193 dvbsub_parse_init, 00194 dvbsub_parse, 00195 dvbsub_parse_close, 00196 };