Stereo rca, yes? Then that means the digital tracks are being converted to analogue inside the player, so you're not getting the actual pcm content. To do that you need a player with S/PDIF output. With analogue the sound quality will depend on how good the DACs are, and how well the circuitry is shielded against electrical interference.
You can get DTS audio over digital connection, but to capture AC3 you need an external RF demodulator.