A stream is only written to the output container when it has a complete header.
ssc->ssc_hg is only set when a decoded packet contains extradata.
MPEG2VIDEO never contains extradata in the packets so ssc->ssc_hg is never set and mpeg2 video will never report a complete header.

by removing this check transcoding to mpeg2video is working again.
Merge branch 'master' of github.com:1stsetup/tvheadend
Merge branch 'master' into libav-11beta