Comparison of videos with reference frame not starting from zero

webrtc/tools/compare_videos.py

 #!/usr/bin/env python
 # Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
 #
 # Use of this source code is governed by a BSD-style license
 # that can be found in the LICENSE file in the root of the source
 # tree. An additional intellectual property rights grant can be found
 # in the file PATENTS.  All contributing project authors may
 # be found in the AUTHORS file in the root of the source tree.
 
 import optparse
@@ skipping 30 matching lines @@
                           'will assume we can find it in barcode_tools/'
                           'relative to this directory.'))
   parser.add_option('--ffmpeg_path', type='string',
                     help=('The path to where the ffmpeg executable is located. '
                           'If omitted, it will be assumed to be present in the '
                           'PATH with the name ffmpeg[.exe].'))
   parser.add_option('--zxing_path', type='string',
                     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',
+                    default='stats_deprecated.txt',
+                    help=('DEPRECATED and ignored'))

[kjellander_webrtc, 2017/01/04 14:47:07]

I suggest having --stats_file_test read from this value if it's specified +
print a warning during execution that --stats_file is DEPRECATED but that its
value is being used.

If not specified, --stats_file_test should just use its own value.

If we just ignore its value, the test in Chrome will break when we land this CL
and it gets rolled in. 

[kjellander_webrtc, 2017/01/09 12:12:19]

You raised the point off-review that the test won't fail if the value of the
flag is ignored. You're absolutely right about that, the test don't use the
stats file for anything (but it's contents might be interesting for debugging a
failed test etc, so it's still interesting). As long as the flag exists until
the call to compare_video.py in
https://cs.chromium.org/chromium/src/chrome/browser/media/webrtc/webrtc_video...
is updated, this is fine.

I think we should just remove the passing of the flag entirely in that test,
since it will then just use the default value.

   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 not options.ref_video:
     parser.error('You must provide a path to the reference video!')
   if not os.path.exists(options.ref_video):
     parser.error('Cannot find the reference video at %s' % options.ref_video)
 
   if not options.test_video:
     parser.error('You must provide a path to the test video!')
   if not os.path.exists(options.test_video):
     parser.error('Cannot find the test video at %s' % options.test_video)
 
   if not options.frame_analyzer:
     parser.error('You must provide the path to the frame analyzer executable!')
   if not os.path.exists(options.frame_analyzer):
     parser.error('Cannot find frame analyzer executable at %s!' %
                  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.
 
   A simple invocation is:
   ./webrtc/tools/barcode_tools/compare_videos.py
   --ref_video=<path_and_name_of_reference_video>
   --test_video=<path_and_name_of_test_video>
   --frame_analyzer=<path_and_name_of_the_frame_analyzer_executable>
 
   Notice that the prerequisites for barcode_decoder.py also applies to this
   script. The means the following executables have to be available in the PATH:
   * zxing
   * ffmpeg
   """
   options = _ParseArgs()
 
   if options.barcode_decoder:
     path_to_decoder = options.barcode_decoder
   else:
     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.
   cmd = [
     options.frame_analyzer,
     '--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:
     print 'Failed to run frame analyzer.'
     return 1
 
   return 0
 
 if __name__ == '__main__':
   sys.exit(main())