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M2Tech HiFace 2? - Page 15

post #211 of 518

EDIT: deleted


Edited by Andrew_WOT - 11/17/12 at 10:17am
post #212 of 518

i am using wasapi.

what makes KS better?

post #213 of 518
Quote:
Originally Posted by oldson View Post

i am using wasapi.

what makes KS better?

 



Even with WASAPI changes to volume in Windows Control Panel affect foobar2000 output, almost like it's still going through kmixer.

KS and WASAPI should be the same, except WASAPI can take higher toll on CPU due to integer to float conversion

 

http://www.m2tech.biz/knowledge.html

Quote:
Windows: WASAPI
WASAPI (Windows Audio Standard API) is a application protocol interface developed for Windows Vista and Seven (it doesn’t exist for Windows XP) which allows for bypassing the kernel mixer without the need for a kernel streaming player or driver. The sound quality that can be obtained using WASAPI is comparable to that obtained in kernel streaming mode. One difference is that WASAPI operates in floating point format, so two conversion are needed (integer-to-floating from the player to WASAPI and floating-to-integer from WASAPI to the driver). This means that WASAPI loads the CPU a little more than plain kernel streaming. On the other hand, WASAPI allows for a wider choice of players. WASAPI is bit-perfect, provided conversion are correctly done.
post #214 of 518

i assume to use KS means insalling a new "plug-in" and disabling the wasapi one??

post #215 of 518

KS should only be used on Windows XP since it doesn't support WASAPI, which is also a bitperfect output method, however it's much more stable and with better compatibility with a wide range of DACs. For Windows Vista/7/8, WASAPI should be used instead.

post #216 of 518
Quote:
Originally Posted by Roller View Post

KS should only be used on Windows XP since it doesn't support WASAPI, which is also a bitperfect output method, however it's much more stable and with better compatibility with a wide range of DACs. For Windows Vista/7/8, WASAPI should be used instead.


Hmm, No.

KS is what recommended by M2Tech regardless of Windows version, of course if the player of choice doesn't support kernel streaming, WASAPI will do just as good. Read the link in my reply.

post #217 of 518

You just install KS component from foobar2000 components page

http://www.foobar2000.org/components

And follow instruction in HiFace manual, all you do is just switching to different output (KS: M2Tech Audio 2.0 Output)

post #218 of 518

Roller is correct.  KS doesn't exist on Windows 7.  Anything resembling functional KS is just a driver catch converting to WASAPI.  Also, Foobar's WASAPI implementation is a whee bit buggy.   JRiver works though, even on Event Style.  KS = XP, WASAPI = W7.  Technically I have the PWD2 and not the HiFace2 but both are XMOS and use the same driver so... ya.


Edited by Solude - 11/18/12 at 4:53pm
post #219 of 518

That's news to me, care to elaborate or point to the source of that discovery. If what you are saying is true, M2Tech has no clue about Windows audio modes as they always recommend KS over anything else and this is how they compare two in their FAQ.

 

 

Quote:
Windows: kernel streaming
Kernel streaming is the most “audiophile” playback mode available in Windows. When a kernel streaming compatible player deals with a kernel streaming compatible device (and driver), data go from the player directly to the driver, by means of a memory buffer which is written by the player and read by the driver. This way, the kernel mixer is totally bypassed and no processing is performed on the data, except that done by the player itself. The kernel streaming mode has another advantage: it requires very few CPU time, so it allows every PC, even the less powerful one, to handle high resolution files without hiccups. Kernel streaming is inherently bit-perfect.
Windows: WASAPI
WASAPI (Windows Audio Standard API) is a application protocol interface developed for Windows Vista and Seven (it doesn’t exist for Windows XP) which allows for bypassing the kernel mixer without the need for a kernel streaming player or driver. The sound quality that can be obtained using WASAPI is comparable to that obtained in kernel streaming mode. One difference is that WASAPI operates in floating point format, so two conversion are needed (integer-to-floating from the player to WASAPI and floating-to-integer from WASAPI to the driver). This means that WASAPI loads the CPU a little more than plain kernel streaming. On the other hand, WASAPI allows for a wider choice of players. WASAPI is bit-perfect, provided conversion are correctly done.
post #220 of 518

They also think SPDIF is 5Vpp so um ya, I'll stop there ;)

post #221 of 518
Quote:
Originally Posted by Solude View Post

They also think SPDIF is 5Vpp so um ya, I'll stop there ;)


But can you please reveal the source of your intel (KS not SPDIF)? :)

 

BTW, this one is from Hiface Two manual.

 

 

Quote:
6.2. Configuring a PC with Windows Vista or Windows 7
A PC with Windows Vista or Windows 7 can use hiFace Two in four different ways: Direct
Sound (DS), Kernel Streaming (KS), WASAPI and ASIO. DS is suitable for players which
can’t operate in Kernel Streaming mode nor with WASAPI or for Internet streaming; KS
can be chosen (for better performance) with players which can operate in Kernel
Streaming mode (such as FooBar, Winamp, Monkey Media, JRiver). WASAPI (Windows
Audio Standard API) is a standard interface for audio players which allows to get the same
performance of KS with applications which can’t operate in KS mode, at the cost of higher
CPU load. Much the same can be told about ASIO.

Edited by Andrew_WOT - 11/18/12 at 6:19pm
post #222 of 518

Without boring you with a MSDN article explaining how to code W7 audio...

 

http://en.wikipedia.org/wiki/Windows_legacy_audio_components

 

Also from a player point of view...

 

http://wiki.jrmediacenter.com/index.php/Audio_Output_Modes

post #223 of 518

Both links says nothing about KS being removed, yes WASAPI is preferred programming model that *allows* avoid kernel programming, that's it.

This article on the other hand provides more insight on changes made to Audio architecture in Vista and beyond

http://support.creative.com/kb/ShowArticle.aspx?sid=25937

Click on Details, to open the article up, apparently KS is still there with good ole NT days WDM, and still remains the most direct path to audio driver.

 

Or this article

http://promos.chooch.us/archives/479

 

 

Quote:

WDM KS (Windows Driver Model / Kernel Streaming) has been around since Windows 98. WMD is a universal driver structure and behavior making it possible to use a single binary driver for Windows 98 through Win7. Kernel Streaming is just what it sounds like: audio and video streams directly through the Windows Kernel offering extremely low latency. The kernel, if you’re wondering, is really the heart of an Operating System – being the lowest level software that everything else is built upon.

Since Windows 2000, MME and DirectSound are actually built on top of WDM/KS – so obviously you want to go WDM native to remove the extra layer between your software and equipment.

WASAPI (Windows Audio Session API) was introduced with Windows Vista, but hasn’t seen wide adoption because it doesn’t really provide anything that Kernel Streaming doesn’t and generally doesn’t provide better performance than ASIO.

So, WASAPI is in a weird mid point where it overlaps, but doesn’t bring much new to the table. In addition, it doesn’t provide sample rate conversion, so it requires all audio streams to use the same sample rate as the audio hardware (same as Ardour and JACK under Linux) which can either be a confusing pain the ass, or give a hit in audio quality because an application has poor conversion code.


Edited by Andrew_WOT - 11/18/12 at 8:57pm
post #224 of 518

KS wasn't removed on Windows Vista/7/8, it is simply too buggy to be considered on modern OSes. Unfortunately, there are still many audio hardware manufacturers that have guides on how to set up computers in order to have optimal audio playback, but they haven't been updated since legacy Windows XP.

 

Users that are running modern OSes basically have two options for bitperfect playback, WASAPI or ASIO (yes, even non-ASIO compliant devices work by adding a wrapper).

post #225 of 518
Quote:
Originally Posted by Andrew_WOT View Post

Both links says nothing about KS being removed

 

Oh I don't know, the word obsolete to me tends to indicate that to me.  Or that KS specifies working in XP but not Win7.  Tell you what, you find me the MSDN article that says KS is alive in Windows 7 and that WASAPI didn't replace it as the exclusive mode ;)

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