What is the gain (advantage) of oversampling and noise shaping in D/A conversion?
If you play 16-bit audio at 48kHz, you need the DAC analog reconstruction filter to pass 20kHz and attenuate 96dB at 24kHz, which is quite steep and requires complex multistage analog filter.
The advantage of using oversampling is moving the sampling rate much higher, for example oversampling by 4x means the DAC runs at 192kHz, and the analog filter only needs to pass 20kHz and block 96dB at 96kHz, which allows for much simpler filter.
The noise shaping is much like dithering after signal processing, but instead of adding white noise uniformly to the whole band, it weights the noise to high frequencies above the audio band, which can then be filtered away by the DAC reconstruction filter, so less noise remains on the audio band, thus increasing the apparent signal-to-noise ratio of the audio band.