diff --git a/record-and-playback/core/lib/recordandplayback/generators/video.rb b/record-and-playback/core/lib/recordandplayback/generators/video.rb
index d5efbd69a3cfa40ce270f654a8044e1631314283..616302b75bb77ec7ae59ae19d8b2a3ff93cb6a06 100755
--- a/record-and-playback/core/lib/recordandplayback/generators/video.rb
+++ b/record-and-playback/core/lib/recordandplayback/generators/video.rb
@@ -163,7 +163,7 @@ module BigBlueButton
   #  video - the video file. Must not contain an audio stream. 
   def self.multiplex_audio_and_video(audio, video, video_out)
     BigBlueButton.logger.info("Task: Multiplexing audio and video")      
-    command = "#{FFMPEG_CMD_BASE} -i #{audio} -i #{video} -map 1:0 -map 0:0 #{video_out}"
+    command = "#{FFMPEG_CMD_BASE} -i #{audio} -i #{video} -map 1:0 -map 0:0 -ar 44100 #{video_out}"
     BigBlueButton.execute(command)
     # TODO: check result, raise an exception when there is an error
   end