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