Sometimes this may happen. You can use the AUDIO SYNC function to delay the audio output to match the video. 1. During the playback, press and hold the AUDIO SYNC button until AUDIO SYNC XXX appears on the display. XXX stands for audio delay time, the unit of the delay time is millisecond. 2. Press the VOL +/- buttons on the remote control to set the delay time for audio output within 5 seconds until you find the video synchronizes with the audio.