1D DWT unwanted color shift.

Hello. I would like to ask you for a help. I'm writing a script for 1D dwt and idwt. Input data are spectral values on one pixel of a 3D image (300x300x224). My scripts are finally working but there is some unwanted shift in color. I can't figure out where it happens. I tried matlab's built-in functions and they work fine but I don't want to use them - I want to do the proces "manually".

In my opinion the convolution part is correct. The shifting is probably a result of a bad subtraction of the convolved signal (which is otherwise too long - I think (1,240)).

Please help me. I really don't know how to correct it.

Encoder script

INPUT=(1,224)

[LoD,HiD] = wfilters('db9','d');

L=length(input);
F=length(LoD);

x_l = conv(input,LoD);                %Convolving
x_l = x_l(F:2:(F+L-2));               %Decimation and subtracting the wavelet length

x_h = conv(input,HiD);                %Covolving
x_h = x_h(F:2:(F+L-2));               %Decimation and subtracting the wavelet length

% final output is [x_l x_h]

OUTPUT=2x(1,112)

Decoder script

INPUT=(1,224)

[LoR,HiR] = wfilters('db9','d');

L=length(input);
F=length(LoR);

mid_val=ceil((length(input))/2); %selecting middle value

x_l=input(1:mid_val); %dividing signal to LP and HP parts
x_h=input(mid_val+1:L);

x_l=upsample(x_l,2); %inserting 0 at even indexes
x_h=upsample(x_h,2); 

x_l=conv(x_l,LoR);
x_h=conv(x_h,HiR);

x_l=x_l(F:F+L-1);
x_h=x_h(F:F+L-1);
% final output is  [x_l + x_h]

OUTPUT=2x(1,112)