On MAIN page of options select an Interface mode: Advanced (all options are accessible) or Simple (the basic options. If you only began acquaintance with ProgDVB can select this).
When you selecting a stability mode (demands the more resources of the ??) the interface and a process engine more reliably works.
The demultiplexer (wiki) is responsible for convergence of video and audio streams, for their synchronization. At present considered the best is demux from Microsoft.
In the INTERFACE section you can adjust a program general view- to select a skin, to choose interface language (Russian, English, German, French, Hungarian, Italian, Portuguese, Chinese, Spanish, Arabian).
Additional skins you can download from ProgDVB site.
On the same page are choosing the type of remote control and assignment of buttons. In more details about it look here.