jit.vcr, issues with audio recording

I want to record video from 1 source and audio from another. In order to avoid issues with synchronisation, I use jit.vcr. It works well, recording video and audio and putting it into one .mov file. BUT: there's something wrong when recording the audio:

1) There seems to be a slip of around 500 ms og the .mov,where there is no sound

2) I use line for creating an envelope in order to avoid clicks. For some reason the changes in volume are not recorded, - the sound starts with a click.

I have made a patch with a totally comparable situation between jit.vcr and sfrecord. The latter works fine. Envelope is ok, and the file works as usual. The former does the described rarities.

Please check my patch, and tell me what I'm doing wrong: