This filter has not got any attention at all and it simply looks like enabling/disabling audio/video ended unfinished. So I will finish it properly for the next release.
Thanks for reporting!
The output video has wrong length with the fade effect applied.
With my tests, the file, that was processed with fade and then converted to the DVCPRO, produces output file 2 frames longer. Same workflow with the fade bypassed produces correct length.