for those who are able to interpret all the measurements: is there any audible degradation by using directsound vs. wasapi exclusive, all else being equal (same player, no resampling by directsound, etc)?
I believe you are missing a key point here. DirectSound is
perfectly capable of bit perfect playback if
all the following conditions are satisfied –
- That the system sampling rate matches that of the of audio being played. This bypasses the need for Windows to perform any undesirable sampling rate conversion
- That there are no other demands on the Windows audio system. This will cause your audio and the disturber to be mixed together
- That something prevents any further demands on the Windows audio system throughout the time that the system is being used for 'serious' audio.
WASAPI is not, fundamentally, some system that causes Windows audio to sound ‘different’ (it has no way to do so). It is merely a means of ensuring that the above conditions are satisfied on a continuing basis. If affords a relatively simple means for an audio application to specify
- the sampling rate (etc.) it wants
- to lock the audio system out to other users
- to ensure the above at your playback application's pleasure
It's interesting to note that, largely for reasons of flexibility, ASIO does not generally offer the exclusivity that guards the audio system from interference from would-be disturbers. If, for whatever reason, you have to use ASIO, a useful workaround for this limitation is to ensure that your DAC (or whatever) is
not the default audio device. If your DAC (or whatever) is not the default device then it must,
by definition, be exclusive provided no other running app. is attempting to send audio to that device.