Got a broken webm file

[wlo1844651]

I add almost 300 frames to make a 21 sec video.
There was no error message, however it return a webm with correct width, height and time length but the scene is whole black, and it can't be played.

The following is where I called whammy:
var whammy = new Whammy.Video();
whammy.add(webpDataURL, time);
var output = whammy.compile();

Is there any suggestion or limit I missed it?

[conundrumer]

here's the fix:

chrahunt/TagProReplays@0468714#diff-e86e17cf209c8a7f8d42905e3990ce2cR157

I'm gonna fork and submit a PR