WASAPI and bit depth question

[yamamoto2002]

On WASAPI exclusive playback, device bit depth is not important when source PCM bit depth is 16bit.

 

On WASAPI shared playback, when shared mode device bit depth is set to 16bit, TPDF dither is added somewhere in the Windows audio engine and LSB information is lost. When shared mode device bit depth is set to 24bit or 32bit, the TPDF dither is not added. Therefore if 16bit music is played using WASAPI shared mode, it is better to set shared mode device bit depth to 24bit or 32bit rather than 16bit.

 

[yamamoto2002]

18 hours ago, Miska said:

 

 S/PDIF is always 24-bit (24 bits of audio data and 8 bits of aux data).

 

20bits of audio sample and 4bits of aux sample.

 

S/PDIF sends bit depth (word length) using channel status word. I checked RME Fireface 400 S/PDIF output and found word length == 24 even when playing audio with 16bit WASAPI device bit depth !