/******************************************************************** * * * THIS FILE IS PART OF THE OggTheora SOFTWARE CODEC SOURCE CODE. * * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS * * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE * * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING. * * * * THE Theora SOURCE CODE IS COPYRIGHT (C) 2002-2009 * * by the Xiph.Org Foundation and contributors http://www.xiph.org/ * * * ******************************************************************** function: last mod: $Id: decinfo.c 16503 2009-08-22 18:14:02Z giles $ ********************************************************************/ #include <stdlib.h> #include <string.h> #include <limits.h> #include "decint.h" /*Unpacks a series of octets from a given byte array into the pack buffer. No checking is done to ensure the buffer contains enough data. _opb: The pack buffer to read the octets from. _buf: The byte array to store the unpacked bytes in. _len: The number of octets to unpack.*/ static void oc_unpack_octets(oc_pack_buf *_opb,char *_buf,size_t _len){ while(_len-->0){ long val; val=oc_pack_read(_opb,8); *_buf++=(char)val; } } /*Unpacks a 32-bit integer encoded by octets in little-endian form.*/ static long oc_unpack_length(oc_pack_buf *_opb){ long ret[4]; int i; for(i=0;i<4;i++)ret[i]=oc_pack_read(_opb,8); return ret[0]|ret[1]<<8|ret[2]<<16|ret[3]<<24; } static int oc_info_unpack(oc_pack_buf *_opb,th_info *_info){ long val; /*Check the codec bitstream version.*/ val=oc_pack_read(_opb,8); _info->version_major=(unsigned char)val; val=oc_pack_read(_opb,8); _info->version_minor=(unsigned char)val; val=oc_pack_read(_opb,8); _info->version_subminor=(unsigned char)val; /*verify we can parse this bitstream version. We accept earlier minors and all subminors, by spec*/ if(_info->version_major>TH_VERSION_MAJOR|| _info->version_major==TH_VERSION_MAJOR&& _info->version_minor>TH_VERSION_MINOR){ return TH_EVERSION; } /*Read the encoded frame description.*/ val=oc_pack_read(_opb,16); _info->frame_width=(ogg_uint32_t)val<<4; val=oc_pack_read(_opb,16); _info->frame_height=(ogg_uint32_t)val<<4; val=oc_pack_read(_opb,24); _info->pic_width=(ogg_uint32_t)val; val=oc_pack_read(_opb,24); _info->pic_height=(ogg_uint32_t)val; val=oc_pack_read(_opb,8); _info->pic_x=(ogg_uint32_t)val; val=oc_pack_read(_opb,8); _info->pic_y=(ogg_uint32_t)val; val=oc_pack_read(_opb,32); _info->fps_numerator=(ogg_uint32_t)val; val=oc_pack_read(_opb,32); _info->fps_denominator=(ogg_uint32_t)val; if(_info->frame_width==0||_info->frame_height==0|| _info->pic_width+_info->pic_x>_info->frame_width|| _info->pic_height+_info->pic_y>_info->frame_height|| _info->fps_numerator==0||_info->fps_denominator==0){ return TH_EBADHEADER; } /*Note: The sense of pic_y is inverted in what we pass back to the application compared to how it is stored in the bitstream. This is because the bitstream uses a right-handed coordinate system, while applications expect a left-handed one.*/ _info->pic_y=_info->frame_height-_info->pic_height-_info->pic_y; val=oc_pack_read(_opb,24); _info->aspect_numerator=(ogg_uint32_t)val; val=oc_pack_read(_opb,24); _info->aspect_denominator=(ogg_uint32_t)val; val=oc_pack_read(_opb,8); _info->colorspace=(th_colorspace)val; val=oc_pack_read(_opb,24); _info->target_bitrate=(int)val; val=oc_pack_read(_opb,6); _info->quality=(int)val; val=oc_pack_read(_opb,5); _info->keyframe_granule_shift=(int)val; val=oc_pack_read(_opb,2); _info->pixel_fmt=(th_pixel_fmt)val; if(_info->pixel_fmt==TH_PF_RSVD)return TH_EBADHEADER; val=oc_pack_read(_opb,3); if(val!=0||oc_pack_bytes_left(_opb)<0)return TH_EBADHEADER; return 0; } static int oc_comment_unpack(oc_pack_buf *_opb,th_comment *_tc){ long len; int i; /*Read the vendor string.*/ len=oc_unpack_length(_opb); if(len<0||len>oc_pack_bytes_left(_opb))return TH_EBADHEADER; _tc->vendor=_ogg_malloc((size_t)len+1); if(_tc->vendor==NULL)return TH_EFAULT; oc_unpack_octets(_opb,_tc->vendor,len); _tc->vendor[len]='\0'; /*Read the user comments.*/ _tc->comments=(int)oc_unpack_length(_opb); len=_tc->comments; if(len<0||len>(LONG_MAX>>2)||len<<2>oc_pack_bytes_left(_opb)){ _tc->comments=0; return TH_EBADHEADER; } _tc->comment_lengths=(int *)_ogg_malloc( _tc->comments*sizeof(_tc->comment_lengths[0])); _tc->user_comments=(char **)_ogg_malloc( _tc->comments*sizeof(_tc->user_comments[0])); for(i=0;i<_tc->comments;i++){ len=oc_unpack_length(_opb); if(len<0||len>oc_pack_bytes_left(_opb)){ _tc->comments=i; return TH_EBADHEADER; } _tc->comment_lengths[i]=len; _tc->user_comments[i]=_ogg_malloc((size_t)len+1); if(_tc->user_comments[i]==NULL){ _tc->comments=i; return TH_EFAULT; } oc_unpack_octets(_opb,_tc->user_comments[i],len); _tc->user_comments[i][len]='\0'; } return oc_pack_bytes_left(_opb)<0?TH_EBADHEADER:0; } static int oc_setup_unpack(oc_pack_buf *_opb,th_setup_info *_setup){ int ret; /*Read the quantizer tables.*/ ret=oc_quant_params_unpack(_opb,&_setup->qinfo); if(ret<0)return ret; /*Read the Huffman trees.*/ return oc_huff_trees_unpack(_opb,_setup->huff_tables); } static void oc_setup_clear(th_setup_info *_setup){ oc_quant_params_clear(&_setup->qinfo); oc_huff_trees_clear(_setup->huff_tables); } static int oc_dec_headerin(oc_pack_buf *_opb,th_info *_info, th_comment *_tc,th_setup_info **_setup,ogg_packet *_op){ char buffer[6]; long val; int packtype; int ret; val=oc_pack_read(_opb,8); packtype=(int)val; /*If we're at a data packet and we have received all three headers, we're done.*/ if(!(packtype&0x80)&&_info->frame_width>0&&_tc->vendor!=NULL&&*_setup!=NULL){ return 0; } /*Check the codec string.*/ oc_unpack_octets(_opb,buffer,6); if(memcmp(buffer,"theora",6)!=0)return TH_ENOTFORMAT; switch(packtype){ /*Codec info header.*/ case 0x80:{ /*This should be the first packet, and we should not already be initialized.*/ if(!_op->b_o_s||_info->frame_width>0)return TH_EBADHEADER; ret=oc_info_unpack(_opb,_info); if(ret<0)th_info_clear(_info); else ret=3; }break; /*Comment header.*/ case 0x81:{ if(_tc==NULL)return TH_EFAULT; /*We shoud have already decoded the info header, and should not yet have decoded the comment header.*/ if(_info->frame_width==0||_tc->vendor!=NULL)return TH_EBADHEADER; ret=oc_comment_unpack(_opb,_tc); if(ret<0)th_comment_clear(_tc); else ret=2; }break; /*Codec setup header.*/ case 0x82:{ oc_setup_info *setup; if(_tc==NULL||_setup==NULL)return TH_EFAULT; /*We should have already decoded the info header and the comment header, and should not yet have decoded the setup header.*/ if(_info->frame_width==0||_tc->vendor==NULL||*_setup!=NULL){ return TH_EBADHEADER; } setup=(oc_setup_info *)_ogg_calloc(1,sizeof(*setup)); if(setup==NULL)return TH_EFAULT; ret=oc_setup_unpack(_opb,setup); if(ret<0){ oc_setup_clear(setup); _ogg_free(setup); } else{ *_setup=setup; ret=1; } }break; default:{ /*We don't know what this header is.*/ return TH_EBADHEADER; }break; } return ret; } /*Decodes one header packet. This should be called repeatedly with the packets at the beginning of the stream until it returns 0.*/ int th_decode_headerin(th_info *_info,th_comment *_tc, th_setup_info **_setup,ogg_packet *_op){ oc_pack_buf opb; if(_op==NULL)return TH_EBADHEADER; if(_info==NULL)return TH_EFAULT; oc_pack_readinit(&opb,_op->packet,_op->bytes); return oc_dec_headerin(&opb,_info,_tc,_setup,_op); } void th_setup_free(th_setup_info *_setup){ if(_setup!=NULL){ oc_setup_clear(_setup); _ogg_free(_setup); } }