libavcodec/dvbsub_parser.c

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

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