[This is
preliminary documentation and subject to change.]
This sample driver demonstrates
the basics of writing an audio GFX filter. On Microsoft Windows XP, only autoload GFXes are allowed. That
means that a GFX can only be applied to specific PnP IDs of USB audio devices.
The sample GFX is therefore tied to the Microsoft DSS 80 USB speakers. You can
modify the INF file and replace the PnP ID with the PnP ID of your USB audio
device to load the GFX on your device.
To build this sample,
enter the free or checked Windows XP build environment and run build
from the parent directory, rather than this subdirectory. This will also
compile the GFX property DLL which allows the user to change the properties of
your GFX.
The INF file named ‘gfxswap.inf’ included in the parent directory can be used
to install the sample driver together with the GFX property DLL after it has
been built. Simply copy the INF and this binary and the GFX property sample
binary to a floppy disk and right click the INF file and choose ‘Install’ on
your test machine. Please also refer to the ‘readme.htm’ file in the parent
directory.
Once the driver has been
installed with the INF, the driver may be updated by copying the binary into
%SystemRoot%\System32\Drivers on the target machine and rebooting to test the
new driver, provided that there are no INF changes.
File Description common.h Header file which includes all necessary header files.
debug.h Defines debug output macros.
device.cpp Device entry point.
filter.cpp Defines the filter and implements all filter properties.
filter.h Defines the filter object and the filter property handlers.
gfx.rc Recourse file to build the filter.
Makefile Makefile …
pin.cpp Implements the pin dispatch handlers and properties.
pin.h Defines the pin object and pin property handlers.
readme.htm This file.
Sources Needed for building the project.