function [db] = compute_features(experiment, src)

  if nargin < 2
    global src;
  end

  N = 5*2^17;
 
  % set the appropriate options for the particular feature set

  options = set_options(experiment);

  % extract features using the computed options

  features = extract_features(experiment, N, options);

  db = prepare_database(src, features);
  db.features = single(db.features);

end
