"You could upmix the matrixed 2-channel Dolby Surround into a "fake" 5.1 mix. IMHO there isn't really a valid reason to do this, I would leave it as it is and just play the audio through a Dolby Pro-logic decoder when watching the DVD."

When I did this, I ran the stereo feed through a "software" DPLII simulator, because my receiver doesn't have this mode. DPLII is especially suited for stereo recordings, whereas DPL works best with DPL recordings. The DPLII streams were extracted and hard-coded in an AC3 stream. It's essentially the same soundtrack you would get from a DPLII receiver. I made it for myself for these reasons (and no, I still don't have a newer receiver.

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