extractFlowVideo.m

% Copyright (C) 2015 Tran Lam An.
% This code is for research, please do not distribute it.

function extractFlowVideo( video_path, flowSavePath, useTVL1 )
%EXTRACTFLOWVIDEO Summary of this function goes here
%   Detailed explanation goes here
%   Input:  video_path
%           flowSavePath
%           useTVL1 --- 1 for TVL1 algorithm, 0 for BroxECCV2004

d = dir(fullfile(video_path, '*.jpg'));

im1 = fullfile(video_path, d(1).name);
for ind = 2:length(d)
    im2 = fullfile(video_path, d(ind).name);
    flow = gpuOpticalFlow(im1, im2, useTVL1);
    im1 = im2;

    scale = 16;
    mag = sqrt(flow(:,:,1).^2+flow(:,:,2).^2)*scale+128;
    mag = min(mag, 255);
    flow = flow*scale+128;
    flow = min(flow,255);
    flow = max(flow,0);

    [x,y,z] = size(flow);
    flow_image = zeros(x,y,3);
    flow_image(:,:,1:2) = flow;
    flow_image(:,:,3) = mag;

    flow_image = uint8(flow_image);
    imwrite(flow_image, fullfile(flowSavePath, num2str(ind-1, '%04d.jpg')));
end

end