Black shark 3 short video is set to lock the screen of the mobile phone without sound?

Black shark 3 short video is set to lock the screen of the mobile phone, and there is no sound. The volume of mobile media is mute. The way to turn on the sound is as follows:

1, open the phone settings.

2. Click the sound option.

3. Select a media volume.

4. Swipe to the right to increase the volume of the media.

5. Click the Save button to exit the phone setup. The media volume is not muted, and a short video of Black Shark 3 will sound when the phone is locked.