jp1_get_siz.m

用matlab实现的JPEG算法

% ------------------------------------------
%  nom : 
%  [M_in,g_color,g_quant,g_XRsiz,g_YRsiz]=jp1_get_SIZ(fid)
%
% ------------------------------------------

function [M,N,P,tcolor,tquant]=jp1_get_SIZ(fid)


[Mext,count]=fread(fid,1,'uint16'); %  SIZ

m_deb = ftell(fid) ;
[jmp,count] =fread(fid,1,'uint16'); % Lsiz
jmp= double(jmp) ;


[Mext,count]=fread(fid,1,'short'); % Rsiz


[Mext,count]=fread(fid,1,'int'); % Xsiz
M=int16(Mext) ;
[Mext,count]=fread(fid,1,'int'); % Ysiz
N=int16(Mext) ;

[Mext,count]=fread(fid,6,'int'); % XOsiz ... YTOsiz

[Mext,count]=fread(fid,1,'int16'); % 
P=int16(Mext) ;

tcolor(1) = int16(fread(fid,1,'int8'));% CSsiz

tXRsiz = [1  1  1];
tYRsiz = [1  1  1];
tquant = [8  8  8];

for i=1:double(P)
 tquant(i)=int16(fread(fid,1,'int8'));	% Ssiz(i) (8bits) MSB pas utilis