Yet Another (WA)SAPI New Technology (YASAPI/NT) Output Plugin for Winamp

Yet Another (WA)SAPI New Technology (YASAPI/NT) Output Plugin for Winamp utilizes the Windows Audio Session API (WASAPI). WASAPI's exclusive mode for rendering audio is a native way on Windows to render audio undisturbed, similar to Steinberg's Audio Stream Input/Output (ASIO). YASAPI/NT Output may serve as a replacement for any other Winamp Output.

In order to understand the difference between YASAPI/NT and it's hijacked predecessor YASAPI read this first.

Nanos gigantum humeris insidentes: This project is dedicated to my European heritage. It is strictly to be understood as a statement against the "sweet" liberal lie of "multiculturalism" which is going to destroy Europe as we know it, in particular against the Merkel regime selling out Europe for nothing as we watch. #TeamWhite

PLEASE NOTE THAT THIS PROJECT IS AN EXPERIMENTAL RATHER THEN AN INDUSTRIAL STRENGTH EFFORT. THIS PROJECT IS NOT FOR YOU. IT IS FOR ME IN ORDER TO LEARN SOMETHING. IF THER'S SOMETHING ALONG THE WAY I CAN DO FOR YOU THAT'S GREAT!

Content

1. News
2. Introduction
3. Sequence Diagram
4. Installation
5. Implementation
6. Configuration
7. References
8. A Message Silently Disappearing from the Winamp Forums
9. Some Additional Notes Regarding the Lovely Parasite 

Note: You may toggle the size of most images by clicking on them.

1. News

If you prefer all entries of section News loaded at start-up you should go here.

Date	Release	Remarks
2020-06-03 pinned		As it seems our days at Sourceforge are counted. At least we’ve received a respective ultimatum: Isn‘t it funny that this is happening at the exact same time as Donald J. Trump is going to crack down all that commie scum? In order to comply with their “policy” we’re not any longer going to let host this page by Sourceforge but have copied it already to http://out-yasapi.sourceforge.net/. Within a few days we’re going to remove it from Sourceforge. 2020-06-06 − Because we’re not willing to follow the orders by Sourceforge this project has to leave. As soon as there’s a domain pbelkner.de available expect a revival of the project. Most likely this page will re-appear at ”http://www.pbelkner.de/software/web/out-yasapi/“, and the project’s releases at ”http://www.pbelkner.de/software/frs/out-yasapi/out_yasapi-2a/“.
2020-05-07		Chris reported that the plug-in seemed not to load on Windows 10. Fortunately, this could be resolved by using the plug-in's gcc version. Hence we changed the default download from msc-bundle to gcc-bundle. Please note that the plug-in is developed on Windows 7.
2019-10-31	2.3.5	Made the plug-in more robust for being run from an unexpected environment. (Many thanks again Ralf!)
2019-10-21	2.3.4	Brought back the dialog for choosing the installation directory of the GTK runtime (cf. below) which for some unknown reason had been vaporized (thanks a lot Ralf.) Corrected counting broken sessions.
2019-06-27		Merkel, it's time to go: Angela Merkel seen shaking uncontrollably for second time in nine days. There are rumors that for years(!) Merkel is plagued by Parkinson's disease and at least never shoud have been candidate for Chancellor in the 2017 elections (watch her 2017 in Mexico.) Update 2019-06-29: Red Ice TV: Merkel Really IS Sick, Shaking Uncontrollably AGAIN. Update 2019-07-10: Angela Merkel shaking for third time in as many weeks.
2019-06-02		In case you try downloading "winamp58_3660_beta_full_en-us.exe" from the source (i.e. from winamp.com) you may experience that it's not possible because their certificate has been expired (already for some time):   It's, of course, possible to download e.g. by means of the wget command: # wget 'https://download.nullsoft.com/winamp/client/winamp58_3660_beta_full_en-us.exe' --no-check-certificate --2019-06-02 07:24:43-- https://download.nullsoft.com/winamp/client/winamp58_3660_beta_full_en-us.exe Resolving download.nullsoft.com (download.nullsoft.com)... 5.39.58.66 Connecting to download.nullsoft.com (download.nullsoft.com)|5.39.58.66|:443... connected. WARNING: cannot verify download.nullsoft.com's certificate, issued by ‘CN=Let's Encrypt Authority X3,O=Let's Encrypt,C=US’: Unable to locally verify the issuer's authority. HTTP request sent, awaiting response... 302 Found Location: https://download.nullsoft.com/winamp/misc/winamp58_3660_beta_full_en-us.exe [following] --2019-06-02 07:24:44-- https://download.nullsoft.com/winamp/misc/winamp58_3660_beta_full_en-us.exe Reusing existing connection to download.nullsoft.com:443. HTTP request sent, awaiting response... 200 OK Length: 8201952 (7.8M) [application/x-msdos-program] Saving to: ‘winamp58_3660_beta_full_en-us.exe’ winamp58_3660_beta_full_en-us 100%[=================================================>] 7.82M 1.68MB/s in 4.8s 2019-06-02 07:24:48 (1.64 MB/s) - ‘winamp58_3660_beta_full_en-us.exe’ saved [8201952/8201952] Update: Seems to be fixed.
2019-05-28	2.3.3	Most likely you've read the following message a few days ago appearing on the Winamp forum: Because of that we ask some of our users we're convinced really exist whether they can confirm because we're on a hopelessly outdated Windows 7 system and hence cannot tell whether it's running on Windows 8.1 or Windows 10 (apart from technical issusses caused by drivers and devices.) As expected, the only thing they confirm is that it's up and running. Many thanks to everyone contributing to the survey! One of the users, Diimaan from India, took the opportunity to report some problems he experienced on his system with exclusive mode where calling the IAudioClient::Initialize method was returning with some error message. Jointly we where able to resolve the issue with exclusive/push (you may have noticed undocumented v2.3.3-β1, v2.3.3-β2, v2.3.3-β3, and v2.3.3-β4 needed for respective communications): The error code returned was AUDCLNT_E_UNSUPPORTED_FORMAT, an error code not documented  for IAudioClient::Initialize, but indeed documented  for IAudioClient::IsFormatSupported. This brouht us to the idea to introduce an additional call to IAudioClient::IsFormatSupported in front of IAudioClient::Initialize and voilà the issue was fixed. (Please note that to our knowledge it is undocumented that calling IAudioClient::IsFormatSupported in front of IAudioClient::Initialize is mandatory.) Unfortunately, it was not possible to resolve the issue with exclusive/pull where on Diimaan's system calling the IAudioClient::Initialize method repeatetdly returns with error AUDCLNT_E_BUFFER_SIZE_NOT_ALIGNED: Error AUDCLNT_E_BUFFER_SIZE_NOT_ALIGNED should be healed by the alignment dance. Unfortunately, this doesn't help here because the alignment dance has alredy taken place (indicated by repeatedly contained in YASAPI/NT's error message.) Anyway, we found a bug in YASAP/NT's implementation of the alignment dance and fixed it. Unfortunately, this doesn't help either (we on our system are not able to test the alignment dance's implemetation because error AUDCLNT_E_BUFFER_SIZE_NOT_ALIGNED is not appearing.) Thanks a lot Diimaan! This release is bundeled with the latest v190528-0620, of the GTK+ runtime.
2019-05-12	2.3.2	A few days after having published the below fix, the issue appeared again on our system. Of course, it is not sufficient to just have the event object in place, we should also fire it when un-pausing! (Viewed this way the additional event object might be completely superfluous - anyway, it doesn't hurt.)
2019-05-12		Ratatosk: German Doomer caught on camera
2019-04-06	2.3.1	load
2019-04-06		Dr. Ludwig: This is Germany (update 2019-09-24: seems to have vaporized, try this link.) Dr. Ludwig: German castles and palaces (update 2019-09-24: seems to have vaporized, try this link.)
2019-03-14		load
2019-02-28	2.3.0	load
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2019-02-02	2.3.0-β13	load
2019-01-14	2.3.0-β12	load
2019-01-10	2.3.0-β11	load
2019-01-06	2.3.0-β10	load
2018-12-31		Lovely Parasite , may we remind you on your promise? Is that all??? Erreicht den Hof mit Mühe und Not; In seinen Armen das Kind war tot. He reaches his courtyard with toil and with dread, – The child in his arms finds he motionless, dead. Johann Wolfgang von Goethe: Erlkönig Not reached yet, surprise, surprise: "the public WACUP preview build is now aimed for the 1st or 2nd" Lovely Parasite  (the future of Winamp ), guess what? We're tired of waiting. Update 19-01-03: The Lovely Parasite  finally has shipped its effort. We've given it a try: First impression: Trying to install in portable mode (on a system partition) crashes. It still comes with a stolen version of this plugin (cf. here and here. BTW: That's the only innovation since ages regarding Winamp's core functionality: audio reproduction.) The plug-in's crash seems to be "fixed" just cosmetically: double buffered mode now simply does not work (without notice.) Summary: This is a "product" nobody needs. Nothing other than GUI gimmicks without any benefit we had to wait for about three years The future of Winamp Because we don't want to further honor the Parasite we've decided to stop commenting on it because we feel that the ones really interested in WASAPI will find their way to this page anyway and will not support the Parasite's effort just because of WASAPI. Thanks again to the talented engineers at Nullsoft who had designed already by the late nineties an API to Winamp still open enough these days for low-latency audio, and the engineers at Microsoft for crafting WASAPI. Update 19-01-05: How does it go that the Parasite's effort (technically nothing other than a wrapper to an outdated Winamp) is hyped by some MSM as soon as it appeares (delayed by half a year according to the Parasite's primary announcement)? Why the Parasite got stuck to an outdated Winamp and does not upgrade to a decent version? Think about it! (Hint to the latter: Even Herrschaftswissen is getting outdated when not getting refreshed ) Update 19-01-19: As of today there's another Lovely Parasite's  victim: Otachan who made the source code of his famous out_asio plug-in publicly available: Update 19-05-23: As an answer to a post hyping the Parasite as the The future of Winamp a message appeared on the WA-forum perfectly nailing down what's going on there: Update 19-05-30: Those SJWs really believe they're the good ones where indeed they're nothing other than crypto-communist parasites, e.g. radio presenter and general purpose nerd: Please note what this particular idiotic SJW is letting us know about his occupation: Evil Genius. MWAHAHAHAhahahahahaaaaaaa. . aaa.aaa.aa...a...a.a *cough cough cough*
2018-12-30	2.3.0-β9	load
2018-12-18	2.3.0-β8	load
2018-12-13	2.3.0-β7	load
2018-12-13	2.3.0-β6	load
2018-12-12	2.3.0-β5	load
2018-12-08	2.3.0-β4	load
2018-12-06	2.3.0-β3	load
2018-12-01	2.3.0-β1	load
2018-11-29		load
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2018-10-20	2.2.0-β5	load
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2018-09-28	2.2.0-β4	load
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2018-09-16	2.2.0-β3	load
2018-09-16	2.2.0-β2	load
2018-09-14		load
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2018-07-15	2.1.0	load
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2018-06-24	2.1.0-β6	load
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2018-06-03	2.1.0-β5	load
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2018-05-27	2.1.0-β4	load
2018-05-20	2.1.0-β3	load
2018-05-18	2.1.0-β2	load
2018-05-13	2.1.0-β1	load
2018-05-09		load
2018-05-06	2.0.0	load
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2018-04-29	2.0.0-β10	load
2018-04-28	2.0.0-β9	load
2018-04-28	2.0.0-β8	load
2018-04-26	2.0.0-β7	load
2018-04-23	2.0.0-β6	load
2018-04-22	2.0.0-β5	load
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2018-04-20	2.0.0-β4	load
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2018-04-11		load
2018-04-08	2.0.0-β1	We're back again: This is a preview of what you might expect to come. It's re-written from scratch with several improvements, hence we called it New Technology (NT). It's our attempt getting rid of annoying nasty Parasites  because we assume that those Parasites  are silly coders just being able to do some silly native win32 GUI coding based on drawn dialogs created with the help of some resource editor and hence we no longer provide a resource file. This NT version is superior to any prior version by any means and does let any prior version look just like a silly prototype: Exclusive pulled (i.e. double bufferered) playback is fully supported. In case of pushed playback a periodic timer may be utilized. This allows for a wonderful symmetric solution compared to pulled playback where no timer is needed at all and playback is triggered in high accuracy by the device itself. Initialization of any resource is deferred until it actually is needed. This way the plug-in's footprint at Winamp start-up time is the lowest possible, i.e. you will not notice whether it is installed. Avoided any instance of busy waiting. In any attempt to fall back on it substituted it by thread synchronization means, i.e. WaitFor[Single/Multiple]Object[s]()/SetEvent() or g_cond_wait()/g_cond_signal() functions, respectively. The GUI (i.e. the Configuration and About dialogs) were made from the great GTK+ toolkit. You might fear that building on Gtk+ might pose some overhead compared to a native Windows implementation: This is, of course, true. But you should note that this is constraint to GUI/configuration and not to playback. As long as you don't make use of the GUI there is no difference to a plain Windows WASAPI implementation. WASAPI is, of course, 100% Windows and nothing else. Loading the GTK+ DLLs in a Winamp session is deferred until the Config or About buttons, respectively, are hit for the first time. To give an impression on the overhead of loading the GTK+ DLLs we display a wait cursor during the time it takes. (Be warned and be patient, especially when GTK+ has to be loaded after re-booting your system!) Once the DLLs required for GTK+ are loaded there is no measurable difference between GTK+ and a native Windows GUI. Last but not least please remember the above note: This was the perfect opportunity for us to dive into the world of GTK+ programming. The result is more than satisfying. This preview has the following limitations: Format conversions (i.e. monto to stereo and bit depth conversions) are not implemented yet. Volume control is not implemented yet. Gapless playback is not implemented yet. The documentation is not fully updated yet. (Updating might continue during the next days.) The documentation of previous versions is available here.
2018-02-16		load
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2016-08-11		Just recently it came to our attention that a creature calling itself "DrO" (update 2018-04-08: according to the silly "one world" ideology ruling the so called "western world" it is just a "human being" without any individual properties discriminating it from others, just like an ant in a bath full of infinite many undistinguishible ants; you shouldn't have any doubt that in a literal sense it is "equal" to you and me by any means, just like in liberté, égalité, fraternité advertises a silly and buggy clone of this plug-in with just a few lines of code errornous changed (out of about 20.000 and his name added to the About box) he advertises under the name of Not So YASAPI Output Plug-in. Be careful and get not mixed up! The original YASAPI plug-in indeed comes from this site and SourceForge (as usual!) Luckily and thanks to the GPL3 the "author" of this silly clone had to leave the original copyright notice and the reference to this site intact! Added the section A Message Silently Disappearing from the Winamp Forums to this documentattion. Added the section Some Additional Notes Regarding the Lovely Parasite  to this documentation.
2016-08-06	1.7.25	load
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2016-07-05	1.7.19	load
2016-07-03	1.7.18	load
2016-07-03	1.7.18	load
2016-07-30	1.7.17	load
2016-07-30	1.7.15	load
2016-06-27	1.7.10	load
2016-06-23	1.7.4	load
2016-06-21	1.7.1	load
2016-06-20	1.7.0	load
2016-06-19	1.6.14	load
2016-06-14	1.6.11	load
2016-06-13	1.6.9	load
2016-06-11	1.6.8	load
2016-06-12	1.6.7	load
2016-06-12	1.6.6	load
2016-06-12	1.6.5	load
2016-05-29	1.6.4	load
2016-05-26	1.6.3	load
2016-05-22	1.6.0	load
2016-05-17	1.5.4	load
2016-05-17	1.5.3	load
2016-05-16	1.5.0	load
2016-04-09	1.0.7	load
2016-01-13	1.0.6	load
2016-01-09	1.0.0	load
2016-01-03	1.16.0	load
2015-12-21	1.16.5	load
2015-12-10	1.14.1	load
2015-12-08	1.14.0	load
2015-12-04	1.11.0	load
2015-11-29	1.10.0	load
2015-11-23	1.9.1	load
2015-11-22	1.9.0	load
2015-11-02		load
2015-10-31	1.8.2	load
2015-10-30	1.8.1	load
2015-10-29	1.8.0	load
2015-10-26	1.7.1	load
2015-10-26	1.7.0	load
2015-10-03	1.6.1	load
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2015-02-14	1.5.0	load
2015-01-30	1.4.0	load
2015-01-25	1.3.0	load
2015-01-24	0.2.1	load
2015-01-24	0.2.0	load
2015-01-23	0.1.0	Initial release.

2. Introduction

According to Microsoft:

The Core Audio APIs were introduced in Windows Vista. This is a new set of user-mode audio components provides client applications with improved audio capabilities. These capabilities include the following:

• Low-latency, glitch-resilient audio streaming.
• Improved reliability (many audio functions have moved from kernel mode to user mode).
• Improved security (processing of protected audio content takes place in a secure, lower-privilege process).
• Assignment of particular system-wide roles (console, multimedia, and communications) to individual audio devices.
• Software abstraction of the audio endpoint devices (for example, speakers, headphones, and microphones) that the user manipulates directly.

Of special interest is that there is an exclusive mode for rendering audio, i.e. there is a mode where an application has exclusive access to the audio device without being disturbed by third parties.

The aim of the YASAPI plug-in is to make the WASAPI exclusive mode for audio rendering available to the users of Winamp.

The name of the plug-in was choosen because there are already at least two WASAPI output plug-in for Winamp:

• Maiko WASAPI output plug-in (used to be at http://maiko.elementfx.com/ but seems to be vanished - you may try https://web.archive.org/web/20150103003246/http://maiko.elementfx.com:80/ instead), and
• adionSoft Winamp WASAPI Output Plugin.

3. Sequence Diagram

The following sequence diagram taken from the documentation v0.1 (describing to some extend YASAPI/NT v2.2-β₅) was created using the impressive plantuml tool.

4. Installation

Installation is as easy as downloading and running the latest NSIS installer from the project's download page.

Even if the plug-in runs without any further Configuration (not very likely) you may wish to configure it. In order to enable configuration you need some GTK runtime. You have two choices to make the plug-in familiar with a GTK runtime:

1. The easy way:
   • From SourceForge, download and run the NSIS installer we've crafted for this purpose: https://sourceforge.net/projects/out-yasapi/files/out_yasapi-nt/.
2. The expert way:
   • On your system install MSYS2 and from within it the 32 bit GTK runtime following the instructions at https://www.gtk.org/download/windows.php.
   • When starting the plug-in's configuration you'll ask where the runtime is located:
      
   • Choose the mingw32 sub-folder (32 bit!) from within the MSYS2 installation.

5. Implementation

There are two sides the YASAPI plug-in has to take into account:

• the WASAPI side, and
• the Winamp side.

The implementation on the WASAPI side follows along the lines of an example provided by Microsoft. The startegy shown in this example is not only applicable for shared mode streams but also for exclusive mode ones, i.e. not the share mode should be emphasized but what is known as the push model. There is also an example demonstrating the pull model in conjunction with the exclusive mode. In that sence there are four strategies:

• push exclusive,
• push shared,
• plull exclusive, and
• plull shared.

The YASAPI plug-in implements the first two strategies, i.e. the ones based on the push model.

The push model, in principle, works as follows:

1. Query the size of the buffer shared with the audio device.
2. Fill in completety the buffer shared with the audio device.
3. Start playing.
4. Loop until the track is played:
   1. Sleep half of the time corresponding to the size of the buffer shared with the audio device.
   2. Into the buffer shared with the audio device, fill in the gap which was growing free by playing during sleep.
5. Sleep until the possibly remaining filled rest of the buffer shared with the audio device was played.
6. Stop playing.

But the YASAPI plug-in not only has to take into account the WASAPI side (the loop consisting of sleeping and writing to the audio device) but also the Winamp side because Winamp provides the audio samples which should be played in an completely unpredictable way.

The YASAPI plug-in decouples the two sides by means of a ring or circular buffer. That way,

• Winamp can luckily write to the ring buffer whenever it likes without caring about WASAPI, and
• WASAPI can luckily read from the ring buffer and write to the audio device whenever it likes without caring about Winamp.

According to step 2 of the push model sketched above, it shoud become clear that the ring buffer should be at least as large (or larger) as the buffer the plug-in's WASAPI component shares with the audio device.

6. Configuration

The YASAPI/NT plug-in comes with a configuration dialog which described in the following. The configuration dialog's top region presents the most important parameters:

• Combo box Device lets you chose the WASAPI enabled device installed on your system the plug-in should use,
• Combo box Mode lets you chose whether the choosen device should be operated in WASAPI mode Shared or Exclusive,
• Combo box Strategy lets you chose whether the choosen device should be operated with WASAPI strategy Push or Pull.
• You should note that Mode Exclusive combined with Strategy Pull is exceptional in that it is Double Buffered whereas the other combinations of Mode and Strategy are not.

Below the top region you find a notebook control consisting of five pages:

• Page Common  is for setting common (i.e. non device specific) parameters,
• Page WASAPI  is for setting device specific parameters w.r.t. Microsoft WASAPI,
• Page YASAPI/NT  is for setting device specific parameters w.r.t. YASAPI/NT,
• Page Monitor  is for monitoring YASAPI/NT, and
• Page Explore  is for exploring capabilities of Microsoft WASAPI.

The notebook control's first page labelled Common looks as follows:

• Checkbox Report Latency Instead of Time  lets you configure some subtle optimization: if enabled, all WASAPI calls are eliminated from GetOutputTime() and GetWrittenTime() and the functions return zero and the latency resuting from the plug-in's buffer, respectively. This should work for almost all input plug-ins because of an example regarding the implementation of getouputime() Nullsoft is given for input plug-ins in their Winamp SDK and which maintains it's own absolute time decode_pos_ms and subtracts away the output plug-in's absolute time and what remains is the difference mod.outMod->GetWrittenTime()-mod.outMod->GetOutputTime() (mod.outMod is the output plug-in, i.e.that's us) what is our undestanding of latency.
• Combo box Play Mono as Stereo  lets you chose whether mono should be treated as stereo (i.e. the one mono channel should be duplicated) the following way:
  • whether the convertion is switched off (i.e. no duplication),
  • whether the the mono channel is plain duplicated,
  • whether the the mono channel multiplicated by the factor ½ (just right shifted by one bit without any fancy dithering) is duplicated, or
  • whether the the mono channel multiplicated by the factor 1/√2 (just rounded without any fancy dithering) is duplicated.
• Checkbox Volume Control  lets you chose whether Winamp's volume control should be enabled (not implemented yet),
• Checkbox Surround  is needed to fill in a a missing peace of information not provided by the Winamp architecture (cf. field dwChannelMask of the WAVEFORMATEXTENSIBLE structure), i.e. lets you chose how 4, 6, and 8 channels shoud be interpreted: as surround, 5.1 surround, and 7.1 surround (enabled), or as quadrophonic, 5.1, and 7.1 (disabled), respectively.
• Checkbox Disconnect when Pause  lets you choose betwen the more expensive mode of throwing away the plug-in's instance of IAudioClient during Pause and creating and initializing a new one when done (enabled) and the less epensive one of avoiding these operations (disabled). (In almost all cases you might prefer the more expensive one.)
• Checkbox Gapless Playbeck  does just that, enables gapless playback (not implemented yet).
• Combo box Configuration Dialog Position  lets you define where the Configuration dialog should be positionend in Z-order, i.e.
  • whether it is free floating,
  • whether it is on top of the Preferences dialog, or
  • whether it always on top.
  If the Configuration dialog is visible in order to let the option take effect you should do the following:
  • Hit Commit.
  • Open Winamp → Preferences and hit again the Configure button.
  • Close Winamp → Preferences.
• Combo box About Dialog Position  lets you define where the About dialog should be positionend in Z-order, i.e.
  • whether it is free floating,
  • whether it is on top of the Preferences dialog, or
  • whether it always on top.
  If the About dialog is visible in order to let the option take effect you should do the following:
  • Hit Commit.
  • Open Winamp → Preferences and hit again the About button.
  • Close Winamp → Preferences.

On the next page labeled WASAPI there are the following per device options:

• Label Mode  repeats what is choosen on top of the dialog by means of combo box Mode and lets you further refine in case it's Shared:
  • Checkbox Autoconvert PCM  should always be checked because otherwise any format different from what is configured by means of Control Panel → Sound → Properties → Advanced
    
    will result in an error. (BTW: In case you're also interested in Exclusive Mode playback you should ensure that both checkboxes labeled Exclusive Mode are checked which they are by default.)
  • Checkbox SRC Default Quality   s enabled in case checkbox Autoconvert PCM is checked and it lets you chose whether (according to Microsoft's documentation regarding AUDCLNT_STREAMFLAGS_SRC_DEFAULT_QUALITY) "a sample rate converter with better quality than the default conversion but with a higher performance cost is used. This should be used if the audio is ultimately intended to be heard by humans as opposed to other scenarios such as pumping silence or populating a meter."
• Label Device Period  is associated with what is choosen on top of the dialog by means of Combobox Mode. According to Microsoft's documentation regarding the IAudioClient::GetDevicePeriod method "[Default] specifies the [...] period for a shared-mode stream. [Minimum] specifies the [...] period for an exclusive-mode stream."
• Label Strategy  repeats what is choosen on top of the dialog by means of combo box Strategy and lets you further refine in case it's Push:
  • Checkbox Periodic Timer  lets you define whether the waitable timer object YASAPI/NT uses in order to implement strategy Push is set-up either periodically with a frequency matching a playback cycle or whether it is re-started again with each playback cycle.
• Checkbox Associate with "Pro Audio" Task:  If you're looking at the example Microsoft is given on how playback for Shared Mode streams should be implemented and compare it with the example on how it shoud be done with Exclusive Mode streams one obvious difference is that the latter calls AvSetMmThreadCharacteristics and AvRevertMmThreadCharacteristics wheras the former not. It's these calls you swich on or off with this checkbox. Hence this checkbox should at least be checked with sharing Exclusive and strategy Pull.
• Checkbox Alignment Dance  lets you configuere whether YASAPI/NT should do the "alignment dance" when error AUDCLNT_E_BUFFER_SIZE_NOT_ALIGNED occurs with IAudioClient::Initialize.

On the next page labeled YASAPI/NT there are the following per device options:

• Combo box Bit Depth  is intended to extend the bit depth from 16 to 24 by padding one zero byte. Even if it works for the inverse it's not a good idea to make use of it because the superfluous bits are just thrown away.
• Slider Max. Latency  is needed because any output plug-in needs to report the maximum latency as a result of the open() function: returns max latency. Unfortunately we don't have enough information when open() is called. This might be the case later in time when write() is called. Instead of inventing an complicated algorithm which is wrong in almost all cases we had a better idea: we put the burden on you, the end user!. You might have an eye on the Monitor page and after having tried all your input and dsp plug-ins you might easily adjust this slider accordingly.

The next page labeled Monitor looks the following:

The final page labeled Explore looks the following:

From the above sketch of the push model it shold be clear that the following relation holds (which is enforced by the configuration dialog):

minimum size of the buffer shared with the device (provided by WASAPI) <= size of buffer shared with the device <= number of samples in the ring buffer before start playing <= size of ring buffer

Please note that no option takes effect before hitting the OK button.

7. References

Just to name a few we'd like to thank (in no particular order)

• the engineers at Nullsoft who once created
  • the Winamp media player,
  • the Milkdrop music vizualizer, and
  • the Nullsoft Scriptable Install System (NSIS),
• the engineers at Microsoft
  • for crafting WASAPI, and
  • for providing community editions of their compiler and tools,
• the GTK+ team
  • for creating this great GUI toolkit,
  • especially for providing a GTK+ port to Windows,
• the MinGW project for providing the GNU C compiler and tools on Windows,
• Alexey Pavlov for providing the MSYS2 environment,
• Bram Moolenaar for crafting the gvim editor,
• Arnaud Roques for creating the impressive plantuml tool,
• Richard Stallman for crafting the GPL, and
• SourceForge for providing this great platform for publishing open source software.

8. A Message Silently Disappearing from the Winamp Forums

The following message posted by me to the top-level (sticky) thread Winamp News in forum the Winamp Discussion forum silently disappeared without any comment:

Dear DJ Egg,

I'm not certain whether you are the right person to address my reqest.. I'm not even certain about who rules this forum. My impression is that you are the only one "official" left (i.e. one with a contract to the owners of Winamp). All the rest including this forum's moderators seem to be volunteers.

As you may have noticed, since some time I have a conflict with some of the former contractors of Winamp, "DrO", regarding the question of intellectual property. As it turns out, this former contractor, "DrO", disrespects intellectual property. He advertises a product he calls "Not So YASAPI Output Plug-in v1.0 Beta" which is a close to 100% clone of YASAPI (cf. here for details).

As it turns out that at the blog of "DrO" some of his fanboys comment we know by their nicknames are frequent posters of this forum, among them some Pawel:

Could you please investigate whether this Pawel is identical to this forum's moderator with the same nickname and in case it turns out to be true fire him from his job as a moderator?

Thank you in advance and best regards,

Peter

9. Some Additional Notes Regarding the Lovely Parasite 

On his blog the Lovely Parasite  claims:

That's of course true. And I'm the last one to have ever told something different. But if doing so, changing just a few lines of code out of about 20.000 just in order to rectify putting his name on the product I consider a clear case of plagiarism:

For further details refer to the Winamp forum.

The Lovely Parasite's  further explanations are simply laughable:

Darren, it's not your WASAPI plug-in, it's mine. Even with that little changes you've made you've perfectly demonstrated that you don't have the slightest idea on how this (my) plug-in is supposed to work and you've managed introducing a major bug into the configuration.

Update 2018-02-16:

Meanwhile the Lovely Parasite  on his web site confirms that his buggy GPL clone is just a fake and that he's distributing (by violating YASAPI's license) a non GPL version to registered so called "beta testers":

As it seems, this way he (the "Hero Member" , what kind of people are attracted by such a spast?) likes to trick users into registering.