What is the reason why mp4' s square dance is played on the mobile EvD just like there is no sound?

Hello, dear. I hope I can help. 1 You can play the downloaded MP4 on mobile phones, tablets and computers. Is there a sound? If there is no sound, there is something wrong with the file. If there is sound, you should check whether the audio cable of EVD is plugged in correctly. There will be no sound if the cable is broken or the speaker is broken or the contact is poor. You can try to plug it in again or change the line.