parse_video();

%% 
function parse_video(resize_shape, crop_flag)
% 
% Parsing video (*.mp4/*.avi) file(s) into image (*.jpg) files
% 
% Written by Hio-Been Han, hiobeen.han@kaist.ac.kr
%
% 2020-09-30
%
if nargin < 1, resize_shape = [448 448]; end
if nargin < 2, crop_flag = false; end

%% (1) Get file info & set save directory
[file_list, vid_directory] = uigetfile('*.*','MultiSelect','on');
if ischar(file_list),  file_list = {file_list}; end
img_directory = [ 'data/frames/'];
if ~isdir(img_directory), mkdir(img_directory); end
convert_resolution = sprintf( '%dx%d', resize_shape(1),resize_shape(2));
save_format = '.jpg';

%% (2) Parse video into JPEG files
for fileIdx = 1:length(file_list)
    
    % Set save directory
    fname = file_list{fileIdx};
    uniqname = fname(1:end-4);
    fileformat = fname(end-3:end);
    vidname = [vid_directory uniqname];
    save_directory = [img_directory uniqname '/'];
    if ~isdir(save_directory), mkdir(save_directory); end
    
    % Read frames
    v = VideoReader( [ vidname fileformat ]);
    nFrames = v.Duration * v.FrameRate;
    for frameIdx = 1:nFrames
        if v.hasFrame
            frame = v.readFrame();
            
            % Set ROI
            if frameIdx == 1
                if crop_flag
                    mask = image_ROI_selection(frame, ['Select ROI to save' ...
                        ' [Occlusion => Right Click]']);
                else
                    mask = logical(ones([size(frame,1), size(frame,2)]));
                end
                idx_x = find( nanmean(mask,2) );
                idx_y = find( nanmean(mask,1) );
                original_resolution = sprintf( '%dx%d', size(frame,1), size(frame,2));
            end
            
            % Save frame
%             frame_valid = rgb2gray( frame(idx_x,idx_y,:) );
            frame_valid = rgb2gray( frame(:,60:end-60,:) );
            imgname_write = [num2str(sprintf('frame-%06d',frameIdx))...
                '-' uniqname '-from' original_resolution '-to' convert_resolution save_format];
            imwrite( imresize( frame_valid, resize_shape ), [ save_directory imgname_write ] )
        end
    end
end
end