.webm video merge failed

[llk2yq]

let _audio = document.querySelector("#my-audio"); // ../assets/audio.mp3
let _video = document.querySelector("#my-video"); // https://my-host.com/video-name.webm
merger.addMediaElement("_audio", _audio, {});
merger.addMediaElement("_video", _video, {
    mute: true,
});
merger.start();
let outputElement = document.querySelector<HTMLVideoElement>("#output");
outputElement.srcObject = merger.result;
outputElement.autoplay = true;

The code above doesnt work, the result video was always loading.

When I changed the video path to https://my-host.com/another.mp4, it merged normally.