快速实现一个简单的SuperpoweredAdvancedAudioPlayer

Question

I am trying to implement a simple SuperpoweredAdvancedAudioPlayer in swift. I successfully modified the SuperpoweredCrossExample project so that playerA plays the song on starting the application.

ViewController.mm now looks like this:

#import "ViewController.h"
#import "SuperpoweredAdvancedAudioPlayer.h"
#import "SuperpoweredFilter.h"
#import "SuperpoweredRoll.h"
#import "SuperpoweredFlanger.h"
#import "SuperpoweredIOSAudioIO.h"
#import "SuperpoweredSimple.h"
#import <stdlib.h>

#define HEADROOM_DECIBEL 3.0f
static const float headroom = powf(10.0f, -HEADROOM_DECIBEL * 0.025);

/*
 This is a .mm file, meaning it's Objective-C++.
 You can perfectly mix it with Objective-C or Swift, until you keep the member variables and C++ related includes here.
 Yes, the header file (.h) isn't the only place for member variables.
 */
@implementation ViewController {
    SuperpoweredAdvancedAudioPlayer *playerA;
    SuperpoweredIOSAudioIO *output;

    float *stereoBuffer, volA;
    unsigned int lastSamplerate;
}

void playerEventCallbackA(void *clientData, SuperpoweredAdvancedAudioPlayerEvent event, void *value) {
    if (event == SuperpoweredAdvancedAudioPlayerEvent_LoadSuccess) {
        ViewController *self = (__bridge ViewController *)clientData;
        self->playerA->setBpm(126.0f);
        self->playerA->setFirstBeatMs(353);
        self->playerA->setPosition(self->playerA->firstBeatMs, false, false);
    };
}


// This is where the Superpowered magic happens.
static bool audioProcessing(void *clientdata, float **buffers, unsigned int inputChannels, unsigned int outputChannels, unsigned int numberOfSamples, unsigned int samplerate, uint64_t hostTime) {
    __unsafe_unretained ViewController *self = (__bridge ViewController *)clientdata;
    if (samplerate != self->lastSamplerate) { // Has samplerate changed?
        self->lastSamplerate = samplerate;
        self->playerA->setSamplerate(samplerate);
    };

    bool silence = !self->playerA->process(self->stereoBuffer, false, numberOfSamples, self->volA);


    if (!silence) SuperpoweredDeInterleave(self->stereoBuffer, buffers[0], buffers[1], numberOfSamples); // The stereoBuffer is ready now, let's put the finished audio into the requested buffers.

    return !silence;
}

- (void)viewDidLoad {
    [super viewDidLoad];
    [self f];
}

- (void) f {
    volA = 1.0f * headroom;
    if (posix_memalign((void **)&stereoBuffer, 16, 4096 + 128) != 0) abort(); // Allocating memory, aligned to 16.

    playerA = new SuperpoweredAdvancedAudioPlayer((__bridge void *)self, playerEventCallbackA, 44100, 0);
    playerA->open([[[NSBundle mainBundle] pathForResource:@"lycka" ofType:@"mp3"] fileSystemRepresentation]);

    output = [[SuperpoweredIOSAudioIO alloc] initWithDelegate:(id<SuperpoweredIOSAudioIODelegate>)self preferredBufferSize:12 preferredMinimumSamplerate:44100 audioSessionCategory:AVAudioSessionCategoryPlayback channels:2 audioProcessingCallback:audioProcessing clientdata:(__bridge void *)self];
    [output start];

    playerA->play(false);
}

- (void)dealloc {
    delete playerA;
    free(stereoBuffer);
#if !__has_feature(objc_arc)
    [output release];
    [super dealloc];
#endif
}

- (void)interruptionStarted {}
- (void)recordPermissionRefused {}
- (void)mapChannels:(multiOutputChannelMap *)outputMap inputMap:(multiInputChannelMap *)inputMap externalAudioDeviceName:(NSString *)externalAudioDeviceName outputsAndInputs:(NSString *)outputsAndInputs {}

- (void)interruptionEnded { // If a player plays Apple Lossless audio files, then we need this. Otherwise unnecessary.
    playerA->onMediaserverInterrupt();
}
@end

I am trying to use the same code in swift following the same method used in SuperpoweredFrequencies project to import c++ files in swift.

Superpowered.h :

#import <UIKit/UIKit.h>

@interface Superpowered: NSObject
-(void) f;
@end

Superpowered.mm :

#import "Superpowered.h"

#import "Superpowered/Headers/SuperpoweredAdvancedAudioPlayer.h"
#import "Superpowered/Headers/SuperpoweredFilter.h"
#import "Superpowered/Headers/SuperpoweredRoll.h"
#import "Superpowered/Headers/SuperpoweredFlanger.h"
#import "Superpowered/SuperpoweredIOSAudioIO.h"
#import "Superpowered/Headers/SuperpoweredSimple.h"
#import <stdlib.h>


#define HEADROOM_DECIBEL 3.0f
static const float headroom = powf(10.0f, -HEADROOM_DECIBEL * 0.025);

/*
 This is a .mm file, meaning it's Objective-C++.
 You can perfectly mix it with Objective-C or Swift, until you keep the member variables and C++ related includes here.
 Yes, the header file (.h) isn't the only place for member variables.
 */
@implementation Superpowered {
    SuperpoweredAdvancedAudioPlayer *playerA;
    SuperpoweredIOSAudioIO *output;

    float *stereoBuffer, volA;
    unsigned int lastSamplerate;
}

void playerEventCallbackA(void *clientData, SuperpoweredAdvancedAudioPlayerEvent event, void *value) {
    if (event == SuperpoweredAdvancedAudioPlayerEvent_LoadSuccess) {
        Superpowered *self = (__bridge Superpowered *)clientData;
        self->playerA->setBpm(126.0f);
        self->playerA->setFirstBeatMs(353);
        self->playerA->setPosition(self->playerA->firstBeatMs, false, false);
    };
}


// This is where the Superpowered magic happens.
static bool audioProcessing(void *clientdata, float **buffers, unsigned int inputChannels, unsigned int outputChannels, unsigned int numberOfSamples, unsigned int samplerate, uint64_t hostTime) {
    __unsafe_unretained Superpowered *self = (__bridge Superpowered *)clientdata;
    if (samplerate != self->lastSamplerate) { // Has samplerate changed?
        self->lastSamplerate = samplerate;
        self->playerA->setSamplerate(samplerate);
    };

    bool silence = !self->playerA->process(self->stereoBuffer, false, numberOfSamples, self->volA);


    if (!silence) SuperpoweredDeInterleave(self->stereoBuffer, buffers[0], buffers[1], numberOfSamples); // The stereoBuffer is ready now, let's put the finished audio into the requested buffers.

    return !silence;
}

- (void)f {

    volA = 1.0f * headroom;
    if (posix_memalign((void **)&stereoBuffer, 16, 4096 + 128) != 0) abort(); // Allocating memory, aligned to 16.

    playerA = new SuperpoweredAdvancedAudioPlayer((__bridge void *)self, playerEventCallbackA, 44100, 0);
    playerA->open([[[NSBundle mainBundle] pathForResource:@"lycka" ofType:@"mp3"] fileSystemRepresentation]);

    output = [[SuperpoweredIOSAudioIO alloc] initWithDelegate:(id<SuperpoweredIOSAudioIODelegate>)self preferredBufferSize:12 preferredMinimumSamplerate:44100 audioSessionCategory:AVAudioSessionCategoryPlayback channels:2 audioProcessingCallback:audioProcessing clientdata:(__bridge void *)self];
    [output start];

    playerA->play(false);
}

- (void)dealloc {
    delete playerA;
    free(stereoBuffer);
#if !__has_feature(objc_arc)
    [output release];
    [super dealloc];
#endif
}

- (void)interruptionStarted {}
- (void)recordPermissionRefused {}
- (void)mapChannels:(multiOutputChannelMap *)outputMap inputMap:(multiInputChannelMap *)inputMap externalAudioDeviceName:(NSString *)externalAudioDeviceName outputsAndInputs:(NSString *)outputsAndInputs {}

- (void)interruptionEnded { // If a player plays Apple Lossless audio files, then we need this. Otherwise unnecessary.
    playerA->onMediaserverInterrupt();
}


@end

Project-Bridging-Header.h :

#import "Superpowered.h"

Controller.swift :

 override func viewDidLoad() {
    super.viewDidLoad()
    let s = Superpowered();
    s.f();
 }

When running the app it crashes and gives the following error:

Answer 1

let s = Superpowered(); should be declared outside viewDidLoad() . Declaring it as an instance variable solved the problem.