This sample contains working source code for a kernel-mode software synthesizer that plugs into the Microsoft® DirectMusic® and WDM Audio architectures.
You are encouraged to use this sample code to start building your own software synthesizer. Modify the sample to add your own features.
If you ship your synthesizer to customers, be sure to use the Guidgen program to create a Globally Unique ID (GUID) for your synthesizer so it won't interfere with other synthesizers. Set CLSID_DDKWDMSynth at the top of private.h and ddksynth.inf to be your GUID. You should also set the text in miniport.cpp, ddksynth.rc and ddksynth.inf to describe your synthesizer.
Note: this is a software synthesizer sample, but is also relevant as a hardware driver sample. If you are writing a hardware driver, you should 1) not implement the wave pin, 2) not implement a synthsink nor depend on Render being called from the port (the hardware should notify the miniport if it needs additional work done at buffer render time), and 3) use category RENDER instead of DATATRANSFORM.
Although this sample doesn't show you how to create a user-mode synthesizer, you can start with the user-mode sample to feel out how synthesis and DLS downloads work. We recommend that you try out your ideas and get things working in user-mode before moving to kernel mode. This approach might be easier and save a bit of debugging time.
Open a free or checked DDK build environment, go to the sample directory, and run build. This creates ddksynth.sys in the Objfre or Objchk subdirectories. Before the sample can be used, it must be installed by executing ddksynth.inf.
To test the synthesizer, open DirectMusic Producer and open the Port Configuration window. (You can do this by right-clicking the button showing a 1 or 2 with a sound wave behind it on the Transit Controls toolbar.) The port name dropdown will now contain the option Microsoft DDK Synthesizer (WDM) in addition to the Microsoft Synthesizer (WDM) option. Set one of the configurations to use the Microsoft DDK Synthesizer port.
Then, when you play music through that configuration, it will be played by the synthesizer you built from the DDK sample. The sound and capabilities of the DDK sample -- Microsoft DDK Synthesizer (WDM) -- are virtually identical to the kernel-mode DirectMusic synthesizer -- Microsoft Synthesizer (WDM). One major exception is that the DDK sample synthesizer does not support reverb.
The DDK sample synthesizer has been tested in checked and free builds with Microsoft Visual C++® version 6. It has been tested on Alpha, but not on 64-bit platforms.
Plug and Play as well as Power Management are supported by PortCls on behalf of the synthesizer.
File Descriptionadapter.cpp Implementation of WDM adapter clist.cpp Implements a simple list data structure clist.h Prototypes for clist.cpp common.h Master header file control.cpp CControlLogic implementation csynth.cpp CSynth implementation csynth.h Prototypes for csynth.cpp DDKSynth.rc Resources file containng version information instr.cpp Implements instruments kernhelp.cpp Helper functions to keep code common between user and kernel modes kernhelp.h Prototype file for kernhelp.h makefile Makefile for BUILD environment midi.cpp Implements MIDI events miniport.cpp Implementation of WDM miniport mix.cpp CDigitalAudio mixing functions mmx.cpp MMX-optimized mixing functions muldiv32.h High-resolution multiply-divide operations plclock.cpp Clock implementation plclock.h Prototypes for plclock.cpp private.h Prototypes for adapter.cpp, miniport.cpp, and syslink.cpp sources Sources file for BUILD environment synth.h Prototypes for instr.cpp, midi.cpp, voice.cpp, and control.cpp syslink.cpp Wave interface back into PortCls voice.cpp Voice implementation
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