The Well-Tempered Computer

An introduction to computer audio

Windows 10

Win10 support FLAC, ALAC and MKV.
A welcome addition.


According to PCAudioLabs latency has improved.

In Windows 7, the lowest latency numbers achieved were at a buffer size of 220 samples for a latency of 5ms.

In Windows 8, the lowest latency numbers achieved were at a buffer size of 179 samples for a latency of 4ms.

In Windows 10, the lowest latency numbers were at a buffer of 132 samples for a latency of 3ms.

Source: PCAudioLabs

According to SonciState:

Audio Core Optimisation - it will now be possible to define and isolate all the core audio processing to a single core, meaning no other processes will be able to interrupt the stream.

Source: SonicState

 

Windows 10 Creators Update (April 2017) added a native USB Audio Class 2 Driver.

Archimago measured its performance and didn’t find any anomalies.

The UAC2 standard was finalized in 2009.

A pity it took MS 8 years to implement it.

It is playback only. The recording part of UAC2 is not implemented.

 

Windows 10 Audio Stack Diagram

Note that WASAPI is the only protocol shown in this diagram.

Indeed one is supposed to use it for audio in either exclusive or shared mode.

These older APIs are deprecated:

Direct Sound

It will do sample rate conversion requiring few resources but it measures poorly.

 

MEASUREMENTS: Windows 10 "Audio Stack" / DirectSound Upsampling - Archimago's Musings

 

The culprit is not the re-sampler but the limiter (CAudioLimiter).

Limiter

Linearity of Windows volume APIs – IAudioMeterInformation and full-scale signals

 

The trick is to lower the output of the media player with 0.2 dB to avoid the limiter to kick in.

More on Direct Sound and how to improve on it can be found here.

 

References

© Vincent Kars July 13, 2021