Initial commit

.gitattributes

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+BassMidiAudioUnitHost/Soundfonts/Soundfont[[:space:]]-[[:space:]]FluidR3[[:space:]]GM[[:space:]](20011225).sf2 filter=lfs diff=lfs merge=lfs -text

.gitignore

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+# Xcode
+#
+# gitignore contributors: remember to update Global/Xcode.gitignore, Objective-C.gitignore & Swift.gitignore
+
+## User settings
+xcuserdata/
+*.pbxuser
+
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+## compatibility with Xcode 8 and earlier (ignoring not required starting Xcode 9)
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+
+## Obj-C/Swift specific
+*.hmap
+
+## App packaging
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+
+## Playgrounds
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+# Code Injection
+#
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+# https://github.com/johnno1962/injectionforxcode
+
+iOSInjectionProject/

BassMidi/Audio Unit/BassMidiAudioUnit.h

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+//
+// BassMidiAudioUnit.h
+// BassMidi
+//
+// Created by Matthieu bouillaud on 17/03/2022.
+//
+
+#import <AudioToolbox/AudioToolbox.h>
+#import <BassMidiAudioUnitFramework/BassMidiDSPKernelAdapter.h>
+#import <AVFoundation/AVFoundation.h>
+
+@interface BassMidiAudioUnit : AUAudioUnit
+
+@property (nonatomic, readonly) BassMidiDSPKernelAdapter *kernelAdapter;
+- (void)setupAudioBuses;
+- (void)setupParameterTree;
+- (void)setupParameterCallbacks;
++ (BOOL)initBassMidi:(UInt32)sampleRate;
+- (BOOL)loadSoundFont:(NSString*)path;
+
+@property (nonatomic) int32_t instrument;
+@property (nonatomic) int32_t transposition;
+@property (nonatomic) BOOL isMuted;
+
+@end

BassMidi/Audio Unit/BassMidiAudioUnit.m

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+//
+// BassMidiAudioUnit.m
+// BassMidi
+//
+// Created by Matthieu bouillaud on 17/03/2022.
+//
+
+#import "BassMidiAudioUnit.h"
+#include <stdint.h>
+#include "bassmidi.h"
+
+@interface BassMidiAudioUnit () {
+ int32_t _instrument;
+ int32_t _transposition;
+ BOOL _isMuted;
+}
+@property (nonatomic, readwrite) AUParameterTree *parameterTree;
+@property AUAudioUnitBusArray *inputBusArray;
+@property AUAudioUnitBusArray *outputBusArray;
+@end
+
+
+@implementation BassMidiAudioUnit
+@synthesize parameterTree = _parameterTree;
+
+#define kInvalidInstrumentCode -1
+
+- (instancetype)initWithComponentDescription:(AudioComponentDescription)componentDescription options:(AudioComponentInstantiationOptions)options error:(NSError **)outError {
+ self = [super initWithComponentDescription:componentDescription options:options error:outError];
+
+ if (self == nil) { return nil; }
+
+ _kernelAdapter = [[BassMidiDSPKernelAdapter alloc] init];
+ _instrument = kInvalidInstrumentCode;
+ _transposition = 0;
+ _isMuted = NO;
+ [self setupAudioBuses];
+ [self setupParameterTree];
+ [self setupParameterCallbacks];
+ return self;
+}
+
+#pragma mark - AUAudioUnit Setup
+
++ (BOOL)initBassMidi:(UInt32)sampleRate {
+ return BASS_Init(0, sampleRate, 0, NULL, NULL);
+}
+
+- (BOOL)loadSoundFont:(NSString*)filePath {
+ NSLog(@"loadSoundFont = %@", filePath);
+ return [_kernelAdapter prepareWithSoundFont:filePath];
+}
+
+- (int32_t)instrument {
+ return _instrument;
+}
+
+- (void)setInstrument:(int32_t)instrument {
+ _instrument = instrument;
+ [_kernelAdapter setInstrument: instrument];
+}
+
+- (int32_t)transposition {
+ return _transposition;
+}
+
+- (void)setTransposition:(int32_t)transposition {
+ _transposition = transposition;
+ [_kernelAdapter setTransposition:transposition];
+}
+
+- (BOOL)isMuted {
+ return _isMuted;
+}
+
+- (void)setIsMuted:(BOOL)isMuted {
+ _isMuted = isMuted;
+ [_kernelAdapter setIsMuted:isMuted];
+}
+
+- (void)setupAudioBuses {
+ // Create the input and output bus arrays.
+ _inputBusArray = [[AUAudioUnitBusArray alloc] initWithAudioUnit:self
+ busType:AUAudioUnitBusTypeInput
+ busses: @[_kernelAdapter.inputBus]];
+ _outputBusArray = [[AUAudioUnitBusArray alloc] initWithAudioUnit:self
+ busType:AUAudioUnitBusTypeOutput
+ busses: @[_kernelAdapter.outputBus]];
+}
+
+- (void)setupParameterTree {
+ // Create parameter objects.
+}
+
+- (void)setupParameterCallbacks {
+ // Make a local pointer to the kernel to avoid capturing self.
+ __block BassMidiDSPKernelAdapter * kernelAdapter = _kernelAdapter;
+
+ // implementorValueObserver is called when a parameter changes value.
+ _parameterTree.implementorValueObserver = ^(AUParameter *param, AUValue value) {
+ [kernelAdapter setParameter:param value:value];
+ };
+
+ // implementorValueProvider is called when the value needs to be refreshed.
+ _parameterTree.implementorValueProvider = ^(AUParameter *param) {
+ return [kernelAdapter valueForParameter:param];
+ };
+
+ // A function to provide string representations of parameter values.
+ _parameterTree.implementorStringFromValueCallback = ^(AUParameter *param, const AUValue *__nullable valuePtr) {
+ AUValue value = valuePtr == nil ? param.value : *valuePtr;
+
+ return [NSString stringWithFormat:@"%.f", value];
+ };
+}
+
+#pragma mark - AUAudioUnit Overrides
+
+- (AUAudioFrameCount)maximumFramesToRender {
+ return _kernelAdapter.maximumFramesToRender;
+}
+
+- (void)setMaximumFramesToRender:(AUAudioFrameCount)maximumFramesToRender {
+ _kernelAdapter.maximumFramesToRender = maximumFramesToRender;
+}
+
+// If an audio unit has input, an audio unit's audio input connection points.
+// Subclassers must override this property getter and should return the same object every time.
+// See sample code.
+- (AUAudioUnitBusArray *)inputBusses {
+ return _inputBusArray;
+}
+
+// An audio unit's audio output connection points.
+// Subclassers must override this property getter and should return the same object every time.
+// See sample code.
+- (AUAudioUnitBusArray *)outputBusses {
+ return _outputBusArray;
+}
+
+// Allocate resources required to render.
+// Subclassers should call the superclass implementation.
+- (BOOL)allocateRenderResourcesAndReturnError:(NSError **)outError {
+ if (_kernelAdapter.outputBus.format.channelCount != _kernelAdapter.inputBus.format.channelCount) {
+ if (outError) {
+ *outError = [NSError errorWithDomain:NSOSStatusErrorDomain code:kAudioUnitErr_FailedInitialization userInfo:nil];
+ }
+ // Notify superclass that initialization was not successful
+ self.renderResourcesAllocated = NO;
+
+ return NO;
+ }
+
+ [super allocateRenderResourcesAndReturnError:outError];
+ _kernelAdapter.musicalContextBlock = self.musicalContextBlock;
+ _kernelAdapter.MIDIOutBlock = self.MIDIOutputEventBlock;
+ if (_instrument != kInvalidInstrumentCode) {
+ [_kernelAdapter setInstrument:_instrument];
+ }
+ [_kernelAdapter setTransposition:_transposition];
+ [_kernelAdapter setIsMuted:_isMuted];
+ [_kernelAdapter allocateRenderResources];
+ return YES;
+}
+
+// Deallocate resources allocated in allocateRenderResourcesAndReturnError:
+// Subclassers should call the superclass implementation.
+- (void)deallocateRenderResources {
+ [_kernelAdapter deallocateRenderResources];
+
+ // Deallocate your resources.
+ [super deallocateRenderResources];
+}
+
+#pragma mark - AUAudioUnit (AUAudioUnitImplementation)
+
+// Block which subclassers must provide to implement rendering.
+- (AUInternalRenderBlock)internalRenderBlock {
+ return _kernelAdapter.internalRenderBlock;
+}
+
+@end

BassMidi/Audio Unit/BassMidiAudioUnit.swift

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+import AVFoundation
+
+public struct BassMidiAudioUnitContainer {
+ public let avAudioUnit: AVAudioUnit
+ public let audioUnit: BassMidiAudioUnit
+}
+
+extension BassMidiAudioUnit {
+
+ enum BassMidiAudioUnitError: Error {
+ case unknown
+ case soundFontLoading
+ }
+
+ private static let subtype: FourCharCode = "bass"
+ private static let manufacturer: FourCharCode = "nwzk"
+ private static let componentName = "nwzk: BassMidi"
+ private static let version: UInt32 = UInt32.max
+ private static var registered = false
+
+ private static let componentDescription: AudioComponentDescription = {
+ // Ensure that AudioUnit type, subtype, and manufacturer match the extension's Info.plist values.
+ var componentDescription = AudioComponentDescription()
+ componentDescription.componentType = kAudioUnitType_MusicDevice
+ componentDescription.componentSubType = subtype
+ componentDescription.componentManufacturer = manufacturer
+ componentDescription.componentFlags = 0
+ componentDescription.componentFlagsMask = 0
+ return componentDescription
+ }()
+
+ private static func register() {
+ guard !registered else { return }
+ AUAudioUnit.registerSubclass(BassMidiAudioUnit.self,
+ as: componentDescription,
+ name: componentName,
+ version: version)
+ registered = true
+ }
+
+ public static func setup(sampleRate: UInt32) {
+ initBassMidi(sampleRate)
+ }
+
+ public static func instantiate(soundFontPath: String, _ completion: @escaping (Result<BassMidiAudioUnitContainer, Error>) -> Void) {
+ BassMidiAudioUnit.register()
+ AVAudioUnit.instantiate(with: componentDescription, options: []) { unit, error in
+ if let unit = unit, let bassMidiAudioUnit = unit.auAudioUnit as? BassMidiAudioUnit {
+ let container = BassMidiAudioUnitContainer(avAudioUnit: unit, audioUnit: bassMidiAudioUnit)
+ guard bassMidiAudioUnit.loadSoundFont(soundFontPath) else {
+ completion(.failure(BassMidiAudioUnitError.soundFontLoading))
+ return
+ }
+ completion(.success(container))
+ } else if let error = error {
+ completion(.failure(error))
+ } else {
+ completion(.failure(BassMidiAudioUnitError.unknown))
+ }
+ }
+ }
+}
+

BassMidi/Audio Unit/BassMidiParameters.swift

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+import Foundation
+import AVFoundation
+
+extension BassMidiAudioUnit {
+
+ private func paramValue(address: AUParameterAddress) -> AUValue? {
+ parameterTree?.parameter(withAddress: address)?.value
+ }
+
+ private func setParam(value: AUValue, address: AUParameterAddress) {
+ parameterTree?.parameter(withAddress: address)?.value = value
+ }
+
+}