Comparison of videos with reference frame not starting from zero

webrtc/tools/compare_videos.py

Index: webrtc/tools/compare_videos.py
diff --git a/webrtc/tools/compare_videos.py b/webrtc/tools/compare_videos.py
index 6aa659be362e4828e809979e4b54d6ffea3aedfe..c4a70c20fed23085c86a1344d4b8ddde95f1af63 100755
--- a/webrtc/tools/compare_videos.py
+++ b/webrtc/tools/compare_videos.py
@@ -48,15 +48,27 @@ def _ParseArgs():
                     help=('The path to where the zxing executable is located. '
                           'If omitted, it will be assumed to be present in the '
                           'PATH with the name zxing[.exe].'))
-  parser.add_option('--stats_file', type='string', default='stats.txt',
+  parser.add_option('--stats_file_ref', type='string', default='stats_ref.txt',
                     help=('Path to the temporary stats file to be created and '
-                          'used. Default: %default'))
+                          'used for the reference video file. '
+                          'Default: %default'))
+  parser.add_option('--stats_file_test', type='string',
+                    default='stats_test.txt',
+                    help=('Path to the temporary stats file to be created and '
+                          'used for the test video file. Default: %default'))
+  parser.add_option('--stats_file', type='string',
+                    help=('DEPRECATED'))
   parser.add_option('--yuv_frame_width', type='int', default=640,
                     help='Width of the YUV file\'s frames. Default: %default')
   parser.add_option('--yuv_frame_height', type='int', default=480,
                     help='Height of the YUV file\'s frames. Default: %default')
   options, _ = parser.parse_args()
 
+  if options.stats_file:
+    options.stats_file_test = options.stats_file
+    print ('WARNING: Using deprecated switch --stats_file. '
+           'The new flag is --stats_file_test.')
+
   if not options.ref_video:
     parser.error('You must provide a path to the reference video!')
   if not os.path.exists(options.ref_video):
@@ -74,6 +86,40 @@ def _ParseArgs():
                  options.frame_analyzer)
   return options
 
+def _DevNull():
+  """On Windows, sometimes the inherited stdin handle from the parent process
+  fails. Workaround this by passing null to stdin to the subprocesses commands.
+  This function can be used to create the null file handler.
+  """
+  return open(os.devnull, 'r')
+
+def DecodeBarcodesInVideo(options, path_to_decoder, video, stat_file):
+  # Run barcode decoder on the test video to identify frame numbers.
+  png_working_directory = tempfile.mkdtemp()
+  cmd = [
+    sys.executable,
+    path_to_decoder,
+    '--yuv_file=%s' % video,
+    '--yuv_frame_width=%d' % options.yuv_frame_width,
+    '--yuv_frame_height=%d' % options.yuv_frame_height,
+    '--stats_file=%s' % stat_file,
+    '--png_working_dir=%s' % png_working_directory,
+  ]
+  if options.zxing_path:
+    cmd.append('--zxing_path=%s' % options.zxing_path)
+  if options.ffmpeg_path:
+    cmd.append('--ffmpeg_path=%s' % options.ffmpeg_path)
+
+
+  barcode_decoder = subprocess.Popen(cmd, stdin=_DevNull(),
+                                     stdout=sys.stdout, stderr=sys.stderr)
+  barcode_decoder.wait()
+
+  shutil.rmtree(png_working_directory)
+  if barcode_decoder.returncode != 0:
+    print 'Failed to run barcode decoder script.'
+    return 1
+  return 0
 
 def main():
   """The main function.
@@ -97,32 +143,11 @@ def main():
     path_to_decoder = os.path.join(SCRIPT_DIR, 'barcode_tools',
                                    'barcode_decoder.py')
 
-  # On Windows, sometimes the inherited stdin handle from the parent process
-  # fails. Work around this by passing null to stdin to the subprocesses.
-  null_filehandle = open(os.devnull, 'r')
-
-  # Run barcode decoder on the test video to identify frame numbers.
-  png_working_directory = tempfile.mkdtemp()
-  cmd = [
-    sys.executable,
-    path_to_decoder,
-    '--yuv_file=%s' % options.test_video,
-    '--yuv_frame_width=%d' % options.yuv_frame_width,
-    '--yuv_frame_height=%d' % options.yuv_frame_height,
-    '--stats_file=%s' % options.stats_file,
-    '--png_working_dir=%s' % png_working_directory,
-  ]
-  if options.zxing_path:
-    cmd.append('--zxing_path=%s' % options.zxing_path)
-  if options.ffmpeg_path:
-    cmd.append('--ffmpeg_path=%s' % options.ffmpeg_path)
-  barcode_decoder = subprocess.Popen(cmd, stdin=null_filehandle,
-                                     stdout=sys.stdout, stderr=sys.stderr)
-  barcode_decoder.wait()
-
-  shutil.rmtree(png_working_directory)
-  if barcode_decoder.returncode != 0:
-    print 'Failed to run barcode decoder script.'
+  if DecodeBarcodesInVideo(options, path_to_decoder,
+                           options.ref_video, options.stats_file_ref) != 0:
+    return 1
+  if DecodeBarcodesInVideo(options, path_to_decoder,
+                           options.test_video, options.stats_file_test) != 0:
     return 1
 
   # Run frame analyzer to compare the videos and print output.
@@ -131,11 +156,12 @@ def main():
     '--label=%s' % options.label,
     '--reference_file=%s' % options.ref_video,
     '--test_file=%s' % options.test_video,
-    '--stats_file=%s' % options.stats_file,
+    '--stats_file_ref=%s' % options.stats_file_ref,
+    '--stats_file_test=%s' % options.stats_file_test,
     '--width=%d' % options.yuv_frame_width,
     '--height=%d' % options.yuv_frame_height,
   ]
-  frame_analyzer = subprocess.Popen(cmd, stdin=null_filehandle,
+  frame_analyzer = subprocess.Popen(cmd, stdin=_DevNull(),
                                     stdout=sys.stdout, stderr=sys.stderr)
   frame_analyzer.wait()
   if frame_analyzer.returncode != 0: