The Oppo 205 has to sabre dacs. Each is dedicated. One of them
is for video playback side of things. The other is for a pure audio channel
for the best possible audio reproduction. Therefore 2 dedicated dacs.
So actually the dacs are not dueling…
Here is a link to the best Oppo 205 discussion forum ever…
The most common reason is that by increasing parallelism you decrease the average error. In practical terms you lower the noise floor by 3dB with each doubling of the number of devices.
The DAC chip you mentioned has eight output channels. If you are creating a stereo DAC you can send the left and right channels each to four outputs and enjoy 6dB lower noise floor than if you used only one output for left and one for right (with six unused).
Building a stereo DAC with two of those eight-channel chips means you can dedicate eight outputs to a single audio channel and get a 9dB improvement in noise floor. It also allows you to design a “dual mono” circuit which reduces electrical cross-talk between left and right channels.
The Oppo player mentioned wanted to be both great at stereo audio but also capable of sending surround sound channels out individual inputs. So I’m guessing one of the chips runs as 4-outputs-per-channel for the front main L/R and the other uses an individual output to each of the additional surround channels.