Online transcoding problem

Hi, Serviio team,
When transcode online source(local streaming from ProgDVB/DVB-C/) always 4-5 seconds after start, freeze for 1 second and after video and sound is not synchronized.
Without transcoding I don't have any problem with synchronisation.
CPU load for transcoding: from 30% to 50% maximum
I set keepStreamOpen="false"
OS: Windows 7 SP1(updated)
Serviio 1.5.1
Please, help me!
P.S.: Sorry for my bad english!
When transcode online source(local streaming from ProgDVB/DVB-C/) always 4-5 seconds after start, freeze for 1 second and after video and sound is not synchronized.
Without transcoding I don't have any problem with synchronisation.
CPU load for transcoding: from 30% to 50% maximum
I set keepStreamOpen="false"
OS: Windows 7 SP1(updated)
Serviio 1.5.1
Please, help me!
P.S.: Sorry for my bad english!