--- a/scripts/merge-features.py	Wed Jul 06 10:18:35 2016 -0400
+++ b/scripts/merge-features.py	Wed Jul 06 10:58:18 2016 -0400
@@ -8,8 +8,8 @@
 parser = argparse.ArgumentParser(description='The program merges feature trajectories recorded from the same site synchronously between start and end time.')
 parser.add_argument('-i', dest = 'metadataFilename', help = 'name of the metadata file', required = True)
 parser.add_argument('-n', dest = 'siteId', help = 'site id or site name', required = True)
-parser.add_argument('--start', dest = 'startTime', help = 'time to start merging features (format %Y-%m-%d %H:%M:%S, eg 2011-06-22 10:00:39)') # if not provided, take common time interval
-parser.add_argument('--end', dest = 'endTime', help = 'time to stop merging features (format %Y-%m-%d %H:%M:%S, eg 2011-06-22 10:00:39)')
+parser.add_argument('-f', dest = 'startTime', help = 'time to start merging features (format %Y-%m-%d %H:%M:%S, eg 2011-06-22 10:00:39)') # if not provided, take common time interval
+parser.add_argument('-l', dest = 'endTime', help = 'time to stop merging features (format %Y-%m-%d %H:%M:%S, eg 2011-06-22 10:00:39)')
 parser.add_argument('-o', dest = 'outputDBFilename', help = 'name of the output SQLite file', required = True)
 
 args = parser.parse_args()
@@ -75,10 +75,7 @@
         try:
             vsConnection = sqlite3.connect(dirname+os.path.sep+videoSequence.getDatabaseFilename())
             vsCursor = vsConnection.cursor()
-            if commonTimeInterval.first < videoSequence.startTime:
-                firstFrameNum = -(videoSequence.startTime-commonTimeInterval.first).seconds*frameRate
-            else:
-                firstFrameNum = (commonTimeInterval.first-videoSequence.startTime).seconds*frameRate
+            firstFrameNum = utils.deltaFrames(videoSequence.startTime, commonTimeInterval.first, frameRate)
             lastFrameNum = (commonTimeInterval.last-videoSequence.startTime).seconds*frameRate
             # positions table
             vsCursor.execute('SELECT * FROM positions WHERE frame_number BETWEEN {} AND {} ORDER BY trajectory_id'.format(firstFrameNum, lastFrameNum))