I ran across a DVD player that has an stereo RCA & an optical out but the box said it outputs 2 channels audio, didn't specify having a pro logic or DD decoder of sorts.
I began to wonder. If this optical were connected to a reciever with IIx EX processor as most have ... wouldn't it sound the same in comparison to another DVD player that does have a decoder built in considering the samling rate is the same and both using an optical output? (isn't it the signal still just re-processed when it goes throught the reciever).
In order to use the built-in decoders on the DVD player, you must use the 5.1 analog connection to connect the player to the receiver. This will bypass the decoders and the bass management of the receiver.
If you want to have Dolby Digital and DTS surrounds, you must use the optical/coaxial digital output or 5.1 analog output. The stereo (left and right) output only gives you Dolby ProLogic surround. The Dolby ProLogic II/IIx decoder on the receiver can be used with Dolby Prologic or stereo sources (tuner, stereo CDs and movies, etc.) to give simulated 5.1/6.1 surround.
Ok. so when it has digital outputs it will output the multi-channel stream... and even if it doesn't specify it has a decoder as long as you connect it to a reciever.. the processing is done there and the difference is nill (eliminate stereo output downmix case please).
OK so if that is the case... lets say that a unit is made that does have a decoder built in.. it sends a decoded signal... but then isn't it "re-processed" or should the reciever be set to "straight" (a setting that is used to turn off processors ) and play the stream the same way that it comes in???? Otherwise I'd imagine the signal gets reprocessed,,, or doesn't it... (i.e. dts output into dts processor vs raw output to dts processor...)
You can't redecode anything. When you switch to 5.1 analog Direct Input (some receivers call it Straight), this will bypass the receiver's decoders and the signal is decoded by the player's DD or DTS decoder. When you switch to regular DVD mode to use optical or coaxial input, the signal is decoded by the receiver's DD or DTS decoder.
Now should we use the receiver's decoders or the player's built-in decoders? It depends on the quality of the decoders on the receiver and the DVD player and also on the crossover settings on these components. The receiver may have better decoders or the player's decoders may be better. Then the crossover setting on the player or receiver may work better for your speaker system and your room. So you need to try both to see which one will work best for you.
One thing I forgot to say to clear the confusion: The digital coaxial or optical output carries the unprocessed signal whereas the analog 5.1 output carries the already decoded signal.