Volume Keyframe Constant type not working properly

[leodf1]

Describe the bug:
The 'Constant' type keyframe for the Volume property does not affect the adjustment instantly, but has a two/four frame tail/fade to the desired level.

Steps to reproduce the behavior:
1.Set a Volume keyframe in the Properties of an audio track, to zero or a lower volume
2. Set the keyframe type to Constant
3. Carefully playback the audio track
4. Notice the audio fades down to the desired level over two frames past the keyframe, instead of setting the level exactly at the keyframe

Expected behavior:
Volume should be set to the desired level exactly at the keyframe point when using the 'Constant' type

System Details:

• OpenShot Version 3.1.1. daily 11751
• Operating System: Windows 10

[leodf1]

Keyframe does not affect the level change instantly at the keyframe point, but instead acts as a short Linear change over two frames past the point. Makes it hard to remove noises etc from the audio track without precise control over the Volume keyframes.

[480P 15FPS PROFILE USED. So might happen across four frames on a 30fps profile, I don't know]

Not sure if this only affects the Volume Property or other Property keyframes too.

Had not noticed this in earlier version, so bug may have been introduced in this version of the software.

tldr: Constant type keyframe acts as a Linear type keyframe