Hello,

If you're usings Windows , try a very good and very compatible VFW Lossless codec called "Ut Video Codec Suite"

(Click link and scroll down to the bottom for latest version  (v8.5.0) )

 

There are four encoding modes:

RGB  -  for regular Poser output

 RGBA  -  for Poser output plus Alpha,

YUV422  -  suitable for capturing live analogue video

YUV420  -  suitable for DV video and DVD video

 

Ut Video Codec appears to "get-along"  better in more applications than Lagarith Lossless does.

 

So,....  render out an image sequence, load them into your editor and save out an AVI  or save out you animation directly from Poser with Ut Video Codec RGBA and the alpha information should be preserved.

 

Take care