Windows 7's resampling sucks, How can it be improved? Options

[googlebot]

Playback over WASAPI must match the sample rate of the output device. Thus applications must supply their own resampling if the playback rate does not match. Most applications don't do this but just employ MME or DirectSound, which provide transparent resampling for non-matching rates.

Since some of my content is 44.1 kHz and some 48 kHz I used to set the output rate to 192 kHz so that all audio had to be upsampled. With good software resampling and a cheap onboard codec this could, in theory, even improve the overall result. But the opposite was true. Today I couldn't longer ignore the impression that the resampled output sounded somewhat muffled and did some measurements.

You can view the result here. The upsampled output (44.1 -> 192 kHz) suffers from quite a HF roll-off in comparison to pure 44.1 kHz output.

In Windows XP the SRC quality could be adjusted. I can't find anything comparable in Windows 7. Does anyone know more?

This post has been edited by googlebot: Feb 9 2011, 20:33

[[JAZ]]

Are you telling me that when I have set 24bits 96Khz in Sounds, and use Wasapi output in foobar2000 to play a 44Khz file, the wasapi driver in foobar is doing its own resampling to 96Khz without me knowing it?

The post you gave is from 2005, and as it can be read in it, not even beta 2 of Windows Vista was released. Also, it is not explicit if he was talking about Wasapi in general, or specifically about exclusive mode. (Or even if exclusive mode was the only mode that was to be made available at that time)

Oh, and btw, i know what WASAPI exclusive mode is. I'm developing an output driver for my application which uses that.


I still don't understand how did you do that.


Win 192 -> analog(?) -> OSX 96Khz -> something -> RMAA 44Khz
Win 44 -> analog(?) -> OSX 96Khz -> something -> RMAA 44Khz

The difference is at most 2dB, where it matters,

So... where it matters is at 18Khz? If you say so...

This post has been edited by [JAZ]: Feb 9 2011, 23:55

[googlebot]

Are you telling me that when I have set 24bits 96Khz in Sounds, and use Wasapi output in foobar2000 to play a 44Khz file, the wasapi driver in foobar is doing its own resampling to 96Khz without me knowing it?

The post you gave is from 2005, and as it can be read in it, not even beta 2 of Windows Vista was released. Also, it is not explicit if he was talking about Wasapi in general, or specifically about exclusive mode. (Or even if exclusive mode was the only mode that was to be made available at that time)

I posted a link to the current MSDN documentation an it is telling you exactly that.

Oh, and btw, i know what WASAPI exclusive mode is. I'm developing an output driver for my application which uses that.

Then I wonder how you can write sentences like "One has to resample only if it uses exclusive mode", which is simply false according to the past and current developer documentation.

I still don't understand how did you do that.

Win 192 -> analog(?) -> OSX 96Khz -> something -> RMAA 44Khz
Win 44 -> analog(?) -> OSX 96Khz -> something -> RMAA 44Khz

It's really no black magic:

RMAA (44.1 kHz) -> DirectSound -> DA (44.1 kHz) -> Line Out (PC) -> Line In (Mac) -> AD (96 kHz) -> WAV -> RMAA Analyzer
RMAA (44.1 kHz) -> DirectSound -> DA ( 192 kHz) -> Line Out (PC) -> Line In (Mac) -> AD (96 kHz) -> WAV -> RMAA Analyzer

Figuratively speaking, WASAPI is nothing more but a revamped XP Audio Kernel with a few added traits ASIO had established.

How do you base such claims. The audio system has undergone a huge rewrite. ASIO isn't faster than WaveRT and there is a nice, modular architecture for any additionally needed features.

This post has been edited by googlebot: Feb 10 2011, 00:28