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Scalable MPEG compression based on DCT coefficients

Scalable MPEG compression based on DCT coefficients


Zahid Ali (view profile)


15 Nov 2006 (Updated )

This application makes 2 layers base Layer and enhancement layer from quantized coefficients


% Root-Mean-Square value(s) for input data
% Efficient MATLAB function for finding RMS values. Accepts N-Dimensional 
% matrices, and computes the column-wise RMS value for N>1, or across any 
% dimension dim if specified by the user.
% Usage:        output = rms(input, dim)

% Hazem Saliba Baqaen.
% MATLAB 7.0
% Credit due to Duane Hanselman for important suggestions

function out = rms(in,dim)

if nargin == 1      % Default (no dim argument specified)
    dim = 1;

if nargin==1 & ndims(in)==2 & any(size(in)==1)        % Can replace this condition with nargin==1 && isvector(in) in MATLAB 7 or higher
    out = norm(in)/sqrt(length(in));        % Faster, but requires 1-Dim data vector
    out = sqrt(sum((in.^2),dim)/size((in),dim));        % Column-wise RMS for [row x column] array or matrix if dim = 1

% For increased speed it is advised to bypass the function call altogether
% and copy and paste part or all of the internal code into your program

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