Transparent background turns black in webm video

[KarapetyannLilit]

Describe the bug
Animated svg transparentbackground turns black with webm format of video
To Reproduce
Please List:
url: url,
viewport: {
width: 1080,
height: 1080,
},
transparentBackground: true,
selector: "svg",
left: 0,
top: 0,
right: 0,
bottom: 0,
fps: 30,
duration: 5,
launchArguments: ["--no-sandbox"],
pixFmt: "yuv420p",
output: ${output}.webm,
quiet: true,

Expected behavior
no error

Desktop (please complete the following information):

• OS: [e.g. Ubuntu LTS 20.04]
• Node Version [e.g. v14.0]
• Timecut Version [e.g. v0.1.4]