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Diffstat (limited to 'portaudio/src/hostapi/wdmks/readme.txt')
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diff --git a/portaudio/src/hostapi/wdmks/readme.txt b/portaudio/src/hostapi/wdmks/readme.txt deleted file mode 100644 index 611acc7..0000000 --- a/portaudio/src/hostapi/wdmks/readme.txt +++ /dev/null @@ -1,85 +0,0 @@ -Notes about WDM-KS host API ---------------------------- - -Status history --------------- -16th January 2011: -Added support for WaveRT device API (Vista and later) for even lesser -latency support. - -10th November 2005: -Made following changes: - * OpenStream: Try all PaSampleFormats internally if the the chosen - format is not supported natively. This fixed several problems - with soundcards that did not take kindly to using 24-bit 3-byte formats. - * OpenStream: Make the minimum framesPerHostIBuffer (and framesPerHostOBuffer) - the default frameSize for the playback/recording pin. - * ProcessingThread: Added a switch to only call PaUtil_EndBufferProcessing - if the total input frames equals the total output frames - -5th September 2004: -This is the first public version of the code. It should be considered -an alpha release with zero guarantee not to crash on any particular -system. So far it has only been tested in the author's development -environment, which means a Win2k/SP2 PIII laptop with integrated -SoundMAX driver and USB Tascam US-428 compiled with both MinGW -(GCC 3.3) and MSVC++6 using the MS DirectX 9 SDK. -It has been most widely tested with the MinGW build, with most of the -test programs (particularly paqa_devs and paqa_errs) passing. -There are some notable failures: patest_out_underflow and both of the -blocking I/O tests (as blocking I/O is not implemented). -At this point the code needs to be tested with a much wider variety -of configurations and feedback provided from testers regarding -both working and failing cases. - -What is the WDM-KS host API? ----------------------------- -PortAudio for Windows currently has 3 functional host implementations. -MME uses the oldest Windows audio API which does not offer good -play/record latency. -DirectX improves this, but still imposes a penalty -of 10s of milliseconds due to the system mixing of streams from -multiple applications. -ASIO offers very good latency, but requires special drivers which are -not always available for cheaper audio hardware. Also, when ASIO -drivers are available, they are not always so robust because they -bypass all of the standardised Windows device driver architecture -and hit the hardware their own way. -Alternatively there are a couple of free (but closed source) ASIO -implementations which connect to the lower level Windows -"Kernel Streaming" API, but again these require special installation -by the user, and can be limited in functionality or difficult to use. - -This is where the PortAudio "WDM-KS" host implementation comes in. -It directly connects PortAudio to the same Kernel Streaming API which -those ASIO bridges use. This avoids the mixing penalty of DirectX, -giving at least as good latency as any ASIO driver, but it has the -advantage of working with ANY Windows audio hardware which is available -through the normal MME/DirectX routes without the user requiring -any additional device drivers to be installed, and allowing all -device selection to be done through the normal PortAudio API. - -Note that in general you should only be using this host API if your -application has a real requirement for very low latency audio (<20ms), -either because you are generating sounds in real-time based upon -user input, or you a processing recorded audio in real time. - -The only thing to be aware of is that using the KS interface will -block that device from being used by the rest of system through -the higher level APIs, or conversely, if the system is using -a device, the KS API will not be able to use it. MS recommend that -you should keep the device open only when your application has focus. -In PortAudio terms, this means having a stream Open on a WDMKS device. - -Usage ------ -To add the WDMKS backend to your program which is already using -PortAudio, you must define PA_USE_WDMKS=1 in your build file, -and include the pa_win_wdmks\pa_win_wdmks.c into your build. -The file should compile in both C and C++. -You will need a DirectX SDK installed on your system for the -ks.h and ksmedia.h header files. -You will need to link to the system "setupapi" library. -Note that if you use MinGW, you will get more warnings from -the DX header files when using GCC(C), and still a few warnings -with G++(CPP). |