ronw@700: % Copyright 2013, Google, Inc.
ronw@700: % Author: Richard F. Lyon
ronw@700: %
ronw@700: % This Matlab file is part of an implementation of Lyon's cochlear model:
ronw@700: % "Cascade of Asymmetric Resonators with Fast-Acting Compression"
ronw@700: % to supplement Lyon's upcoming book "Human and Machine Hearing"
ronw@700: %
ronw@700: % Licensed under the Apache License, Version 2.0 (the "License");
ronw@700: % you may not use this file except in compliance with the License.
ronw@700: % You may obtain a copy of the License at
ronw@700: %
ronw@700: %     http://www.apache.org/licenses/LICENSE-2.0
ronw@700: %
ronw@700: % Unless required by applicable law or agreed to in writing, software
ronw@700: % distributed under the License is distributed on an "AS IS" BASIS,
ronw@700: % WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
ronw@700: % See the License for the specific language governing permissions and
ronw@700: % limitations under the License.
ronw@700: 
ronw@700: function sai_struct = SAI_Run_Segment(sai_struct, input)
ronw@700: % function sai_frame = SAI_Run_Segment(sai_struct, input)
ronw@700: % Compute a single SAI frame from the given multichannel input signal.
ronw@700: 
ronw@700: % Store state used between successive calls to this function in sai_struct.
ronw@700: if ~isfield(sai_struct, 'nap_buffer')
ronw@700:   % Make the history buffer.
ronw@700:   buffer_width = sai_struct.width + ...
ronw@700:       floor((1 + (sai_struct.n_window_pos - 1)/2) * sai_struct.window_width);
ronw@700:   n_ch = size(input, 2);
ronw@700:   sai_struct.nap_buffer = zeros(buffer_width, n_ch);
ronw@700: end
ronw@700: if ~isfield(sai_struct, 'frame')
ronw@700:   % The SAI frame is transposed to be image-like.
ronw@700:   sai_struct.frame = zeros(n_ch, sai_struct.width);
ronw@700: end
ronw@700: 
ronw@700: if size(input, 1) < sai_struct.window_width  % pad out the last result
ronw@700:   input = [input; ...
ronw@700:            zeros(sai_struct.window_width - size(input, 1), size(input, 2))];
ronw@700: end
ronw@700: size(input)
ronw@700: sai_struct.window_width
ronw@700: 
ronw@700: assert(size(input, 1) == sai_struct.window_width)
ronw@700: 
ronw@700: % Shift new data into the buffer.
ronw@700: num_shift = size(input, 1);
ronw@700: sai_struct.nap_buffer = [sai_struct.nap_buffer((1 + num_shift):end,:); ...
ronw@700:                          input];
ronw@700: 
ronw@700: sai_struct = SAI_StabilizeLayer(sai_struct);
ronw@700:   
ronw@700: return