SampleUSBAudioPlugin.cpp
/* |
* File: SampleUSBAudioPlugin.cpp |
* |
* Contains: com_MySoftwareCompany_driver_SampleUSBAudioPlugin Implementation |
* |
* A simple USB audio plug-in that performs a lowpass filtering operation on audio streamed |
* through the Griffin iMic. The target SampleUSBAudioPlugin.kext must be copied to the |
* /System/Library/Extensions folder of the boot volume by an administrator using a |
* command like (from the project folder): |
* |
* sudo cp -rf ./build/SampleUSBAudioPlugin.kext /System/Library/Extensions |
* |
* Then you must notify the operating system that the contents of the kernel extension directory has |
* changed by "touching the directory": |
* |
* sudo touch /System/Library/Extensions |
* |
* Restart the system. |
* |
* After restarting the system, the plug-in should automatically load when the device |
* specified in the Info.plist is plugged in. Plug-in logging can be observed by viewing |
* the system log using Console in /Applications/Utilities. |
* |
* |
* Version: 1.0 |
* |
* Created: 11-23-2004 |
* |
* © Copyright 2004-2013 Apple Computer, Inc. All rights reserved. |
* |
* Disclaimer: IMPORTANT: This Apple software is supplied to you by Apple Computer, Inc. ("Apple") in |
* consideration of your agreement to the following terms, and your use, installation, modification |
* or redistribution of this Apple software constitutes acceptance of these terms. If you do |
* not agree with these terms, please do not use, install, modify or redistribute this Apple |
* software. |
* |
* In consideration of your agreement to abide by the following terms, and subject to these terms, |
* Apple grants you a personal, non-exclusive license, under Apple's copyrights in this |
* original Apple software (the "Apple Software"), to use, reproduce, modify and redistribute the |
* Apple Software, with or without modifications, in source and/or binary forms; provided that if you |
* redistribute the Apple Software in its entirety and without modifications, you must retain this |
* notice and the following text and disclaimers in all such redistributions of the Apple Software. |
* Neither the name, trademarks, service marks or logos of Apple Computer, Inc. may be used to |
* endorse or promote products derived from the Apple Software without specific prior written |
* permission from Apple. Except as expressly stated in this notice, no other rights or |
* licenses, express or implied, are granted by Apple herein, including but not limited to any |
* patent rights that may be infringed by your derivative works or by other works in which the |
* Apple Software may be incorporated. |
* |
* The Apple Software is provided by Apple on an "AS IS" basis. APPLE MAKES NO WARRANTIES, EXPRESS OR |
* IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY |
* AND FITNESS FOR A PARTICULAR PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND OPERATION ALONE |
* OR IN COMBINATION WITH YOUR PRODUCTS. |
* |
* IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL OR CONSEQUENTIAL |
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS |
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) ARISING IN ANY WAY OUT OF THE USE, |
* REPRODUCTION, MODIFICATION AND/OR DISTRIBUTION OF THE APPLE SOFTWARE, HOWEVER CAUSED AND WHETHER |
* UNDER THEORY OF CONTRACT, TORT (INCLUDING NEGLIGENCE), STRICT LIABILITY OR OTHERWISE, EVEN |
* IF APPLE HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
* |
*/ |
#include <IOKit/IOLib.h> |
#include "SampleUSBAudioPlugin.h" |
#define super AppleUSBAudioPlugin |
OSDefineMetaClassAndStructors (com_MySoftwareCompany_driver_SampleUSBAudioPlugin, AppleUSBAudioPlugin); |
// AppleUSBAudioPlugin methods |
/***************************************************** |
* |
* com_MySoftwareCompany_driver_SampleUSBAudioPlugin::pluginInit (IOService * provider, UInt16 vendorID, UInt16 productID) |
* |
* Purpose: |
* |
* Inputs: provider - AppleUSBAudioEngine object associated with device |
* vendorID - idVendor |
* productID - idProduct |
* |
* Returns: IOReturn result - (0 == no error) |
*/ |
IOReturn com_MySoftwareCompany_driver_SampleUSBAudioPlugin::pluginInit (IOService * provider, UInt16 vendorID, UInt16 productID) |
{ |
IOReturn result; |
//IOUSBDevRequest myRequest; |
// Init our superclass first |
result = super::pluginInit (provider, vendorID, productID); |
#warning Change the idVendor & idProduct here (and in Info.plist) to match the audio device you want to use! |
// Double check that we're loaded on the device that we want to be; |
if (vendorID != 0x077D || productID != 0x07AF) |
{ |
//NOTE: Avoid logging this type of information (idVendor, idProduct) in a released product |
//The plug-in should fail silently, if the incorrect (idVendor, idProduct) is given. |
//Only log this type of information during development! |
//IOLog ("vendorID = %u, productID = %u", vendorID, productID); |
return kIOReturnNoDevice; |
} |
if (result == kIOReturnSuccess) |
{ |
// Do our one time initialization |
IOLog ("com_MySoftwareCompany_driver_SampleUSBAudioPlugin initialized successfully\n"); |
/* Just initialize to some random values to verify that pluginSetFormat is working. |
These values should be overwritten by the device's actual format when pluginSetFormat is called. */ |
mSampleRate = 44101; |
mNumChannels = 3; |
setProcessingParameters (&mParamStruct, mSampleRate, mNumChannels); |
} |
return result; |
} |
/***************************************************** |
* |
* com_MySoftwareCompany_driver_SampleUSBAudioPlugin::pluginStart () |
* |
* Purpose: Start processing audio |
* |
* Inputs: (void) |
* |
* Returns: IOReturn result - (0 == no error) |
*/ |
IOReturn com_MySoftwareCompany_driver_SampleUSBAudioPlugin::pluginStart () |
{ |
IOReturn result; |
// Start our superclass first |
result = super::pluginStart (); |
if (result == kIOReturnSuccess) |
{ |
// Do our every time initialization |
resetProcessingState (&mStateStruct); |
IOLog ("com_MySoftwareCompany_driver_SampleUSBAudioPlugin starting.\n"); |
} |
return result; |
} |
/***************************************************** |
* |
* com_MySoftwareCompany_driver_SampleUSBAudioPlugin::pluginReset () |
* |
* Purpose: Reset processing parameters and state. |
* |
* Inputs: (void) |
* |
* Returns: IOReturn result - (0 == no error) |
*/ |
IOReturn com_MySoftwareCompany_driver_SampleUSBAudioPlugin::pluginReset () |
{ |
IOReturn result; |
IOLog ("com_MySoftwareCompany_driver_SampleUSBAudioPlugin resetting...\n"); |
// Reset the plugin's state |
setProcessingParameters (&mParamStruct, mSampleRate, mNumChannels); |
resetProcessingState (&mStateStruct); |
// No need to call super::pluginReset |
result = kIOReturnSuccess; |
return result; |
} |
/***************************************************** |
* |
* com_MySoftwareCompany_driver_SampleUSBAudioPlugin::pluginSetFormat(const IOAudioStreamFormat * const newFormat, const IOAudioSampleRate * const newSampleRate) |
* |
* Purpose: Changes the current audio stream format |
* |
* Inputs: newFormat - new audio stream format |
* newSampleRate- new sample rate |
* |
* Returns: IOReturn result - (0 == no error) |
*/ |
IOReturn com_MySoftwareCompany_driver_SampleUSBAudioPlugin::pluginSetFormat (const IOAudioStreamFormat * const newFormat, const IOAudioSampleRate * const newSampleRate) |
{ |
IOReturn result; |
IOLog ("com_MySoftwareCompany_driver_SampleUSBAudioPlugin changing format\n"); |
// If parameters depend on sample rate or number of channels (or other format info), update them here |
if (NULL != newSampleRate) |
{ |
mSampleRate = newSampleRate->whole; |
} |
if (NULL != newFormat) |
{ |
mNumChannels = newFormat->fNumChannels; |
} |
setProcessingParameters (&mParamStruct, mSampleRate, mNumChannels); |
IOLog ("mSampleRate = %u, mNumChannels = %u\n", (unsigned int)mSampleRate, (unsigned int)mNumChannels); |
// No need to call super::pluginProcess |
result = kIOReturnSuccess; |
return result; |
} |
/***************************************************** |
* |
* com_MySoftwareCompany_driver_SampleUSBAudioPlugin::pluginProcess (float * mixBuf, UInt32 numSampleFrames, UInt32 numChannels) |
* |
* Purpose: Calls processSamples() (low pass filter) to process audio data |
* |
* Inputs: mixBuf - pointer to the mixed buffer samples |
* numSampleFrames - number of sample frames in mixed buffer |
* numChannels - number of channels that are interleaved in the mixed buffer |
* |
* Returns: IOReturn result - (kIOReturnSuccess == no error) |
*/ |
IOReturn com_MySoftwareCompany_driver_SampleUSBAudioPlugin::pluginProcess (float * mixBuf, UInt32 numSampleFrames, UInt32 numChannels) |
{ |
IOReturn result; |
// Do our data processing methods |
if ( (mSampleRate == 44100) |
&& (mNumChannels <= 2)) |
{ |
processSamples (mixBuf, numSampleFrames, numChannels, &mParamStruct, &mStateStruct); |
} |
// No need to call super::pluginProcess |
result = kIOReturnSuccess; |
return result; |
} |
/***************************************************** |
* |
* com_MySoftwareCompany_driver_SampleUSBAudioPlugin::pluginStop () |
* |
* Purpose: Start processing audio |
* |
* Inputs: (void) |
* |
* Returns: IOReturn result - (0 == no error) |
*/ |
IOReturn com_MySoftwareCompany_driver_SampleUSBAudioPlugin::pluginStop () |
{ |
IOReturn result; |
// Do our stop work first, then call super |
IOLog ("com_MySoftwareCompany_driver_SampleUSBAudioPlugin stopping.\n"); |
pluginReset (); |
result = super::pluginStop (); |
return result; |
} |
/***************************************************** |
* |
* com_MySoftwareCompany_driver_SampleUSBAudioPlugin::pluginProcessInput (float * destBuf, UInt32 numSampleFrames, UInt32 numChannels) |
* |
* Purpose: Calls processSamples() (low pass filter) to process audio data |
* |
* Inputs: destBuf - pointer to the input & destination buffer samples |
* numSampleFrames - number of sample frames in mixed buffer |
* numChannels - number of channels that are interleaved in the mixed buffer |
* |
* Returns: IOReturn result - (kIOReturnSuccess == no error) |
*/ |
IOReturn com_MySoftwareCompany_driver_SampleUSBAudioPlugin::pluginProcessInput (float * destBuf, UInt32 numSampleFrames, UInt32 numChannels) |
{ |
// Do our data processing methods |
if ( (mSampleRate == 44100) |
&& (mNumChannels <= 2)) |
{ |
processSamples (destBuf, numSampleFrames, numChannels, &mParamStruct, &mStateStruct); |
} |
return kIOReturnSuccess; |
} |
/***************************************************** |
* |
* com_MySoftwareCompany_driver_SampleUSBAudioPlugin::pluginSetDirection (IOAudioStreamDirection direction) |
* |
* Purpose: Process audio data |
* |
* Inputs: direction - Direction of audio stream, either input or output. |
* numSampleFrames - number of sample frames in mixed buffer |
* numChannels - number of channels that are interleaved in the mixed buffer |
* |
* Returns: IOReturn result - (kIOReturnSuccess == no error) |
*/ |
IOReturn com_MySoftwareCompany_driver_SampleUSBAudioPlugin::pluginSetDirection (IOAudioStreamDirection direction) |
{ |
IOLog ("com_MySoftwareCompany_driver_SampleUSBAudioPlugin set direction - %u\n", (unsigned int)direction); |
mDirection = direction; |
return kIOReturnSuccess; |
} |
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