Audio Fade In

Applies a fade-in effect to the audio track at the start of the video.

video-audio-fade-in accepts a float value in seconds between 0.0 and 1000.0. The audio starts silent and gradually rises to full volume over the specified duration.

For example, video-audio-fade-in=3 fades the audio in over the first 3 seconds of the video.

Use video-audio-fade-out to apply a corresponding fade-out at the end of the video.