Use the timestamp from the meeting ID to calculate the real start time

With the switch to a different clock source in red5, the timestamps
in the events file are no longer real-time, but are rather in
seconds since computer boot.

The timestamp in the meeting id is still realtime, so use that as
the start time. Calculate the end time by adding the meeting length
to the start time.

record-and-playback/presentation/scripts/publish/presentation.rb

@@ -889,9 +889,21 @@ def processChatMessages
 				BigBlueButton::Events.get_start_and_stop_rec_events("#{$process_dir}/events.xml"))
 
 		recording_time = computeRecordingLength()
+
+		# presentation_url = "/slides/" + $meeting_id + "/presentation"
+		@doc = Nokogiri::XML(File.open("#{$process_dir}/events.xml"))
+
+		$meeting_start = @doc.xpath("//event")[0][:timestamp]
+		$meeting_end = @doc.xpath("//event").last()[:timestamp]
 
 		$version = BigBlueButton::Events.bbb_version("#{$process_dir}/events.xml")
 		BigBlueButton.logger.info("Creating metadata.xml")
+
+                # Get the real-time start and end timestamp
+                match = /.*-(\d+)$/.match($meeting_id)
+                real_start_time = match[1]
+                real_end_time = (real_start_time.to_i + ($meeting_end.to_i - $meeting_start.to_i)).to_s
+
 		# Create metadata.xml
 		b = Builder::XmlMarkup.new(:indent => 2)
 
@@ -900,8 +912,8 @@ def processChatMessages
 			b.state("available")
 			b.published(true)
 			# Date Format for recordings: Thu Mar 04 14:05:56 UTC 2010
-			b.start_time(BigBlueButton::Events.first_event_timestamp("#{$process_dir}/events.xml"))
-			b.end_time(BigBlueButton::Events.last_event_timestamp("#{$process_dir}/events.xml"))
+			b.start_time(real_start_time)
+			b.end_time(real_end_time)
 			b.playback {
 				b.format("presentation")
 				b.link("http://#{playback_host}/playback/presentation/playback.html?meetingId=#{$meeting_id}")
@@ -918,11 +930,6 @@ def processChatMessages
 		BigBlueButton.logger.info("Generating xml for slides and chat")
 
 		#Create slides.xml
-		# presentation_url = "/slides/" + $meeting_id + "/presentation"
-		@doc = Nokogiri::XML(File.open("#{$process_dir}/events.xml"))
-
-		$meeting_start = @doc.xpath("//event[@eventname='ParticipantJoinEvent']")[0][:timestamp]
-		$meeting_end = @doc.xpath("//event[@eventname='EndAndKickAllEvent']").last()[:timestamp]
 
 		# Gathering all the events from the events.xml
 		$slides_events = @doc.xpath("//event[@eventname='GotoSlideEvent' or @eventname='SharePresentationEvent']")
@@ -932,8 +939,8 @@ def processChatMessages
 		$cursor_events = @doc.xpath("//event[@eventname='CursorMoveEvent']")
 		$clear_page_events = @doc.xpath("//event[@eventname='ClearPageEvent']") # for clearing the svg image
 		$undo_events = @doc.xpath("//event[@eventname='UndoShapeEvent']") # for undoing shapes.
-		$join_time = @doc.xpath("//event[@eventname='ParticipantJoinEvent']")[0][:timestamp].to_f
-		$end_time = @doc.xpath("//event[@eventname='EndAndKickAllEvent']")[0][:timestamp].to_f
+		$join_time = $meeting_start.to_f
+		$end_time = $meeting_end.to_f
 
 		calculateRecordEventsOffset()