d_gains.m

采用MELP编制的压缩与解码程序

%recover the gains
function [G1,G2,G2pt,G2p_error]=d_gains(G,G2pt,G2p_error)
delta=67/32;
G2=(G(2)+0.5)*delta+10;
if G(1)==0
   if abs(G2-G2pt)>5
      if G2p_error==0
      	G2=G2pt;
   	end
   	G2p_error=1;
	else
   	G2p_error=0;
   end
   G1=0.5*(G2+G2pt);
else
   gain_max=max(G2pt,G2)+6;
   gain_min=min(G2pt,G2)-6;
   if gain_min<10
      gain_min=10;
   end
   if gain_max>77
      gain_max=77;
   end
   G1=(G(1)-1)*(gain_max-gain_min)/6+gain_min;
   G2p_error=0;
end
G2pt=G2;