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More => Old Versions => JRiver Media Center 21 for Windows => Topic started by: DocLotus on August 14, 2015, 04:09:35 pm

Title: WASAPI Exclusive Access... On vs. Off Audio Quality
Post by: DocLotus on August 14, 2015, 04:09:35 pm
Have read all that I can find on WASAPI in the WIKI & on the Web.

There is one little thing that I can find very little about...
Exclusive Access... On vs. Off Audio Quality

Have found only two mentions of the difference between On vs. Off Audio Quality & neither had any real solid evidence of the differences in sound quality.  One simply quoted the fact that On makes a direct connection so it is better. The other said that to their ears the difference was minor.

I can't make that judgement as when I switch from Off to On I have to close out MC, reload MC, listen very carefully & try to remember how the previous sounded all the while the volume is loader with On.

The point being that our audio memory is very short term & not to be trusted.

What I'm wondering is...
Has anyone done an actual instantaneous A-B comparison (at the same sound levels & same sound sources) to see just how much of a difference there is.

If so, how was the test done?
What were your findings?
Title: Re: WASAPI Exclusive Access... On vs. Off Audio Quality
Post by: glynor on August 14, 2015, 05:50:00 pm
Did you read the Exclusive Access article, because all of the details and reasons are pretty much covered there.
http://wiki.jriver.com/index.php/Exclusive_Access
Title: Re: WASAPI Exclusive Access... On vs. Off Audio Quality
Post by: glynor on August 14, 2015, 05:58:18 pm
I can't make that judgement as when I switch from Off to On I have to close out MC, reload MC

Also, this is not true. It can be changed without restarting MC.

You can even make two Zones, one with it enabled and one without (I have this on my setup for the exact reasons detailed in the Wiki article).
Title: Re: WASAPI Exclusive Access... On vs. Off Audio Quality
Post by: DocLotus on August 14, 2015, 06:07:22 pm
Quote
Did you read the Exclusive Access article, because all of the details and reasons are pretty much covered there.

Of course, several times. It address the technical aspect but does not address my main question on this thread which is... what is the real difference in the quality of the sound coming out of the speakers based on real A-B comparisons. It sounds good to me but I really can't tell the difference between Exclusive Excess Off vs. On mainly because the volume is loader with it On.
Title: Re: WASAPI Exclusive Access... On vs. Off Audio Quality
Post by: DocLotus on August 14, 2015, 06:08:37 pm
Quote
I can't make that judgement as when I switch from Off to On I have to close out MC, reload MC

Also, this is not true. It can be changed without restarting MC.

Thanks; I was wondering about that.
Title: Re: WASAPI Exclusive Access... On vs. Off Audio Quality
Post by: glynor on August 14, 2015, 06:10:00 pm
There is no difference if:
* Windows is not playing any other sounds simultaneously.
* You only play files where the sample rate matches the currently selected Windows Default Format

In that case, it is played using the same API and it is still a single-stream to the sound device.

If you play any other file formats, then MC will have to resample them if Exclusive Access is turned off. And, of course, if Windows mixes in other sounds, then other sounds will be mixed in.

Exclusive Access can also make it much more convenient to use Internal Volume because you can enable the Maximize Device Volume (http://wiki.jriver.com/index.php/Maximize_device_volume) setting, and therefore you can easily bypass the system volume mixer.
Title: Re: WASAPI Exclusive Access... On vs. Off Audio Quality
Post by: DocLotus on August 14, 2015, 06:12:07 pm
Quote
You can even make two Zones, one with it enabled and one without (I have this on my setup for the exact reasons detailed in the Wiki article).

Sounds interesting; I've not tried Zones yet.  Can Zones be quickly changed while MC is playing for an A-B comparison?  That would be awesome.
Title: Re: WASAPI Exclusive Access... On vs. Off Audio Quality
Post by: DocLotus on August 14, 2015, 06:20:57 pm
Quote
There is no difference if:
* Windows is not playing any other sounds simultaneously.
* You only play files where the sample rate matches the currently selected Windows Default Format

In that case, it is played using the same API and it is still a single-stream to the sound device.

If you play any other file formats, then MC will have to resample them if Exclusive Access is turned off. And, of course, if Windows mixes in other sounds, then other sounds will be mixed in.

Now we're getting somewhere; MOST interesting.

From what I have read elsewhere on the Web the one or two other folks that brought this up eluded to the same conclusions but they were rather vague about the details.

I really appreciate your input, it is very helpful.

Title: Re: WASAPI Exclusive Access... On vs. Off Audio Quality
Post by: chunky70 on August 16, 2015, 08:03:33 am
Can i just clarify that if i have exclusive mode in windows enabled and play 24/192 flac with direct sound in j river that windows will leave it untouched? With wasapi i'm getting pops and crackles via hdmi (wdm driver).
I have shared mode set at 16/44.1.
I have system sounds turned off.
Windows volume up full.
Title: Re: WASAPI Exclusive Access... On vs. Off Audio Quality
Post by: mwillems on August 16, 2015, 10:15:26 am
Can i just clarify that if i have exclusive mode in windows enabled and play 24/192 flac with direct sound in j river that windows will leave it untouched? With wasapi i'm getting pops and crackles via hdmi (wdm driver).
I have shared mode set at 16/44.1.
I have system sounds turned off.
Windows volume up full.

I'm confused about your setup (you mention the WDM driver but it's unclear what your source is?)

If you're using direct sound 192/24 will be resampled to 16/44.1.  You have to use WASAPI or ASIO to avoid resampling.
Title: Re: WASAPI Exclusive Access... On vs. Off Audio Quality
Post by: chunky70 on August 16, 2015, 10:47:46 am
Sorry i should have made myself clearer.
My source is a small fanless pc, this one here:
http://www.amazon.co.uk/gp/product/B00ZFQQIK0?psc=1&redirect=true&ref_=oh_aui_detailpage_o02_s00
It has both hdmi and analogue out but analogue sounds awful!
Using MC 21 the wdm driver is listed for wasapi and direct sound.
I'm outputting to a hdmi audio extractor then via optical to my dac.
I only have old school stereo amp with analogue inputs.
With direct sound no playback probs.
With wasapi i get pops, crackles and high pitched static noise.
I tried loading ASIO4ALL which was recognised by MC 21 but coudn't get any sound