Dolby Pro Logic was created as one of the first home theater codecs and a few VHS movies had the codec for very basic surround sound. Pro Logic II was developed to convert two-channel sound to multi-channel sound. It has three modes: Movies, Music, & Games. Dolby Digital was created for Laser Disc & Broadcast TV and later for DVD.
If you have two-channel music or movies, try Dolby Pro Logic II. The results are very pleasing.
Read
A Guide to Home Theater Audio Codecs.