ability to increase/decrease volume mid-timeline

[jaco777thomas]

fade in and fade out of the audio (even in the middle of the video)
#meshach

[beniza]

User Story

Description
Audio volume is fixed for an entire clip, with no way to fade or adjust it at specific points in the timeline.

As a video editor, I want to fade audio in or out — including at mid-timeline points — so that I can create smooth and dynamic audio transitions throughout my videos.

Acceptance Criteria

• Users can add volume keyframes at any point on an audio or video track
• Fade-in and fade-out effects can be applied at the start, end, or middle of a clip
• Volume changes are reflected in the preview playback
• The volume envelope is rendered correctly in the exported video