The sound in the video produced by Huishenghuyingx4 and the sound at the end of the imported simple music file gradually become smaller. There are two methods:

1. Select the video or audio on the track Material, the options on the right have fade-in and fade-out icons like mobile phone signals. Click the fade-out icon, and when the music ends, the sound will gradually decrease to nothing.

2. Click the "Mixer" icon above the track, and an audio line will appear in the middle of the track for the video file of the video track or the audio file of the music track. At the appropriate position before the end of the material, click the audio line on the track. The small upward arrow will click a small square on the audio line. Then drag the small square at the end to the bottom, and the sound of the material will gradually decrease to silent. This method can be used to create a gradually lowering sound for any length of time. You can also change the sound level at any time to increase or decrease, just click on the small square on the audio line and adjust it up or down.