Overlaying transparent video

[soapergem]

I am using the latest version of Videopad (13.30) and I am trying to combine two video clips. The first is a standard MP4 video clip, but I have a second WEBM video file, encoded with the VP9 codec, which uses an alpha channel. That second clip is a short stinger that effectively does a stylistic wipe transition, and starts out with a transparent background. However, when I import it into Videopad, that transparent background simply gets rendered as a black background, meaning I can't cleanly overlay it in Video Track 2.

Does Videopad simply not support video codecs that use alpha channels? Or is there something I'm missing?

[borate]

Let's take a look.  Problems can usually be solved if the content is shared.  The process is easy, quick and can be done privately.  Just follow these steps...

•     Back up --- With your project on the timeline, click on MENU at the top-left.  Click FILE|BACK UP PROJECT FILES TO FOLDER.  Choose a folder and SELECT FOLDER.
•     Upload ---  Use a free server - Google Drive, MS OneDrive, etc.* - to upload the saved, numbered FOLDER.    Do NOT upload the individual VPJ or export file. 
•     Get link --- Get a public link.  If using Google Drive, right-click the file and click SHARE. If necessary change "restricted" to "anyone with the link can view" 
•     Share ---     Click COPY LINK | DONE.  Paste that link here, or click the folder at the top-right of this forum to message it privately to me.  It won't be shared.

          *    Before uploading, right-click the folder, click PROPERTIES.  Look at the File Size to confirm that it's not too big for the free space on the server.

[soapergem]

Hi borate, I could send the project file to you if you want it; however in addition to posting here on the forums I also sent a message to the tech support email, and they responded to me with this message earlier today:

Quote

Unfortunately, videos with transparency are not supported.

So it doesn't seem like Videopad will be the right tool to use for this job, at least at this time.

[borate]

Support may not have the full story.  Some video transparency is supported.  Below, a transparent MOV animation overlaid on flames and exported as mp4.

Transparency will be retained in an aPNG export.  And chromakey (green screen) may also be an option on your Webm file, if it has high contrast .

Let's take a look at your project, per the above instructions.