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Windows 7's resampling sucks, How can it be improved?
googlebot
post Feb 9 2011, 20:30
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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
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[JAZ]
post Feb 11 2011, 01:05
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Couple of things...

It looks like foobar2000 implementation of WASAPI uses the exclusive mode. (it doesn't allow other apps to make sound when playing)
I've managed to implement the shared mode, and indeed I wasn't right. The documentation doesn't explicitely say that you cannot use another setting than the one returned to you by the call to GetMixFormat() (Ok, it says it in the page you pointed, but that's not explained in the interface definitions). On the other hand, at least the bitdepth is 32bit float.

In this case, you are right that an application using the shared mode would need to have a resampler if it wants to use multiple samplerates.


I also took the time to install rmaa6 and test this laptop's integrated soundcard with a loopback cable. The results I got are like yours, but I still think you exaggerated.
Having 16bit 44Khz in rmaa, 16bit 192Khz in speakers, and 16bit 44Khz in line in gives me the same graphic that you got (the one with smooth rolloff). If I use 16bit 44Khz -> 16bit 96Khz -> 16bit 44Khz, then the rolloff is still stronger, yet not by much more.

Having all three set to 16bit 44Khz in all doesn't give me as good a graphic than you, it is just partially better, and using 16bit 96Khz in all gives me a very nice response.
comparisons
96Khz

This post has been edited by [JAZ]: Feb 11 2011, 01:11
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Posts in this topic
- googlebot   Windows 7's resampling sucks   Feb 9 2011, 20:30
- - [JAZ]   A) WASAPI doesn't force any player to resampl...   Feb 9 2011, 20:41
|- - googlebot   QUOTE ([JAZ] @ Feb 9 2011, 20:41)...   Feb 9 2011, 21:14
- - saratoga   QUOTE (googlebot @ Feb 9 2011, 14:30) Sin...   Feb 9 2011, 21:56
|- - googlebot   It's hard to ABX the different paths directly ...   Feb 9 2011, 22:11
- - Roseval   WASAPI in exclusive mode send the output straight ...   Feb 9 2011, 23:04
|- - googlebot   QUOTE (Roseval @ Feb 9 2011, 23:04) WASAP...   Feb 9 2011, 23:11
- - Cavaille   QUOTE ([JAZ] @ Feb 9 2011, 20:41)...   Feb 9 2011, 23:43
|- - dv1989   QUOTE (Cavaille @ Feb 9 2011, 22:43) QUOT...   Feb 10 2011, 00:10
- - [JAZ]   Are you telling me that when I have set 24bits 96K...   Feb 9 2011, 23:49
|- - googlebot   QUOTE ([JAZ] @ Feb 9 2011, 23:49)...   Feb 10 2011, 00:07
- - C.R.Helmrich   http://www.hydrogenaudio.org/forums/index....st...   Feb 9 2011, 23:50
- - SCOTU   Is there any reason the OS' resampling even ma...   Feb 9 2011, 23:51
- - soulsearchingsun   Did you take the effects of different recontructio...   Feb 9 2011, 23:56
- - googlebot   I'll be away until tomorrow night. If you guys...   Feb 10 2011, 00:25
- - GeSomeone   @googlebot , I do not fully understand why you...   Feb 10 2011, 00:42
|- - googlebot   QUOTE (GeSomeone @ Feb 10 2011, 00:42) I ...   Feb 11 2011, 00:00
- - Cavaille   QUOTE (googlebot @ Feb 10 2011, 00:07) Ho...   Feb 10 2011, 00:47
- - googlebot   @GeSomeone That's possible. It didn't test...   Feb 10 2011, 00:50
- - SebastianG   I also don't think -1 dB at 17 kHz and -3 dB a...   Feb 10 2011, 11:28
|- - Notat   QUOTE (SebastianG @ Feb 10 2011, 03:28) I...   Feb 10 2011, 16:43
|- - googlebot   I am well familiar with the technical details of r...   Feb 10 2011, 20:46
|- - Woodinville   QUOTE (Notat @ Feb 10 2011, 08:43) Have y...   Nov 5 2011, 08:32
- - soulsearchingsun   QUOTE (soulsearchingsun @ Feb 9 2011, 23...   Feb 10 2011, 11:45
- - lvqcl   http://blogs.msdn.com/b/matthew_van_eerde/...-pull...   Feb 10 2011, 22:17
|- - Greg   QUOTE (lvqcl @ Feb 10 2011, 13:17) http:/...   Apr 17 2011, 08:51
|- - lvqcl   QUOTE (Greg @ Apr 17 2011, 11:51) How exa...   Apr 17 2011, 12:34
|- - Greg   QUOTE (lvqcl @ Apr 17 2011, 03:34) QUOTE ...   Apr 17 2011, 19:30
- - googlebot   Interesting. Looks like it should, just not like w...   Feb 10 2011, 23:32
- - [JAZ]   Couple of things... It looks like foobar2000 impl...   Feb 11 2011, 01:05
- - googlebot   Thank you for the update [JAZ] and my apologies fo...   Feb 11 2011, 01:53
- - googlebot   The problem is mostly solved. It seems to be a rea...   Feb 11 2011, 03:20
|- - soulsearchingsun   QUOTE (googlebot @ Feb 11 2011, 03:20) Th...   Feb 11 2011, 13:05
|- - googlebot   QUOTE (soulsearchingsun @ Feb 11 2011, 13...   Feb 11 2011, 13:09
- - googlebot   Maybe we can get an additional confirmation? Perso...   Feb 11 2011, 13:13
|- - soulsearchingsun   QUOTE (googlebot @ Feb 11 2011, 13:13) Ma...   Feb 11 2011, 13:20
- - googlebot   Full stop. It was just RMAA that fucked up. And wi...   Feb 11 2011, 14:19
- - Cavaille   QUOTE (googlebot @ Feb 11 2011, 14:19) Fu...   Feb 11 2011, 15:15
- - greynol   What about your initial suspicion about muffled so...   Feb 11 2011, 19:51
|- - googlebot   QUOTE (greynol @ Feb 11 2011, 19:51) What...   Feb 11 2011, 20:27
- - hellokeith   Googlebot, This thread was actually helpful, in t...   Feb 13 2011, 04:06
- - jaro1   This area has also my interest, however the proble...   Apr 17 2011, 11:20
- - lvqcl   I don't have it, but it was like the attached ...   Apr 17 2011, 19:57
- - whitejason   QUOTE (googlebot @ Feb 9 2011, 20:30) Pla...   Jun 27 2011, 18:41
- - meeky   Not sure if this is related, but Microsoft have co...   Nov 5 2011, 07:05
- - lvqcl   from the abovementioned thread: QUOTE Media Founda...   Nov 5 2011, 07:36
|- - hellokeith   QUOTE (lvqcl @ Nov 5 2011, 00:36) Media F...   Nov 5 2011, 10:01
|- - benski   QUOTE (lvqcl @ Nov 5 2011, 02:36) from th...   Nov 6 2011, 18:24
- - lvqcl   http://blog.szynalski.com/2009/11/17/an-au...-7/#c...   Nov 5 2011, 10:47
- - C.R.Helmrich   I just checked the optional updates available for ...   Nov 5 2011, 11:28
|- - Batman321   QUOTE (C.R.Helmrich @ Nov 5 2011, 05:28) ...   Nov 5 2011, 19:01
- - Roseval   I'm afraid audio has priority zero at Microsof...   Nov 5 2011, 13:33
|- - googlebot   QUOTE (Roseval @ Nov 5 2011, 14:33) I...   Nov 5 2011, 21:09
- - Roseval   There are a couple of media players for OSX doing...   Nov 6 2011, 10:59
|- - Juha   So, you need dedicated playback software for to do...   Nov 6 2011, 11:52
||- - bennetng   I have to agree that win7's resampling has som...   Nov 6 2011, 13:11
|- - googlebot   QUOTE (Roseval @ Nov 6 2011, 11:59) There...   Nov 6 2011, 15:19
- - Roseval   Correct. iTunes doesn't support automatic samp...   Nov 6 2011, 13:03
- - LordWarlock   For whoever it may interest, there is now a hotfix...   Mar 9 2012, 19:49
|- - C.R.Helmrich   Thanks a million, Lord! Trying it right now. E...   Mar 9 2012, 21:21
|- - extrabigmehdi   QUOTE (LordWarlock @ Mar 9 2012, 18:49) F...   Mar 10 2012, 00:07
||- - andy o   QUOTE (extrabigmehdi @ Mar 9 2012, 16:07)...   Jun 20 2012, 00:34
|- - Woodinville   QUOTE (LordWarlock @ Mar 9 2012, 10:49) F...   Mar 10 2012, 01:51
|- - markanini   QUOTE (Woodinville @ Mar 10 2012, 02:51) ...   Jun 20 2012, 06:41
- - hellokeith   Why a hotfix and not an update?   Mar 10 2012, 10:17
- - db1989   Cross-linking for future reference: “Windows 7/200...   Aug 29 2012, 18:22


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