Merge branch 'output-dir'

* output-dir:
  Document the output-directory parameter.
  Write output to the correct output directory.
  Add an output directory to the output path generator.

Readme.md

@@ -11,11 +11,13 @@ Combine [CppMT][cmt] object tracking data with the original video for verificati
 This program takes a video and associated object tracking data output from [CppMT][cmt] (using the `--output-file` switch) and combines the two, overlaying the bounding box outline and centre point in the output video.
 
 ```shell
-$ cmt-replay <video-input> <data-input>
+$ cmt-replay <video-input> <data-input> [output-directory]
 ```
 
 The output video file is named automatically using the input video filename to ensure that a combination of codec and container that OpenCV can write to is used. For example, an input video file named `video.mp4` will produce an output video file named `video_out.avi`. OpenCV can read the mp4 container but cannot write to it.
 
+If the `output-directory` parameter is supplied the output video file will be written to that directory, otherwise it will be written to the same directory as the input video file.
+
 ## Dependencies
 
 CppMT-replay requires [OpenCV][ocv] version 2.4 to build and run. It is built using [CMake][cmk] version 2.6 or later.

src/main.cpp

@@ -72,9 +72,15 @@ void draw_bbox_centre(Mat frame, vector<float> bbox) {
   circle(frame, centre, 2, draw_colour);
 }
 
-string output_filename(string input_filename) {
+string output_filename(string input_filename, string output_dir="") {
   int dot = input_filename.find_last_of('.');
-  return input_filename.substr(0, dot) + "_out.avi";
+  int out_len = output_dir.length();
+
+  if(out_len > 0 && !(0 == output_dir.compare((out_len - 1), 1, "/"))) {
+    output_dir += '/';
+  }
+
+  return output_dir + input_filename.substr(0, dot) + "_out.avi";
 }
 
 int main(int argc, char **argv) {
@@ -92,8 +98,11 @@ int main(int argc, char **argv) {
   ifstream csv(argv[2]);
   get_next_line_tokens(csv);
 
+  // Generate the full output filename.
+  string out_path = (argc == 4) ? output_filename(argv[1], argv[3]) : output_filename(argv[1]);
+
   // Open output video file.
-  VideoWriter out(output_filename(argv[1]), CV_FOURCC('X', 'V', 'I', 'D'), fps, size, true);
+  VideoWriter out(out_path, CV_FOURCC('X', 'V', 'I', 'D'), fps, size, true);
   if(!out.isOpened()) {
     cerr << "Cannot open output video." << endl;
     return 1;