[Freeswitch-users] mp4 Conference recording is always unplayable 352 bytes file

I have verto-client connecting to a conference. I have setup auto-record pointing to an mp4 file format for mod_conference. I have installed libavcodec-extra, enabled mod_av. The recording seems to start and stop just fine, except the file is just an unplayable 352 bytes. I must have missed something, just can't to figure out what. Am running FreeSWITCH Version 1.6.7-14-d38d065~64bit (-14-d38d065 64bit) on Debian 8.1 Jesse, x64. Please anyone with pointers help. -- David W