使用 DTMF 生成音调并使用 AVAudioPlayer 播放

发布于 2024-09-14 12:17:51 字数 1644 浏览 5 评论 0原文

我想生成自定义 DTMF 音并在 iPhone 上播放。为此，我创建并分配了一个带有自定义音调 (ptr) 的内存缓冲区。现在我想创建一个 NSData 对象，使用内存缓冲区进行初始化，并使用 initWithData:error: 实例方法将其传递给 AVAudioPlayer。

我编写了以下代码，但是当我按下“播放”按钮时，它崩溃了。

#import "AudioPlayerViewController.h"
#include <stdlib.h>
#include <math.h>
#define SIZE 10
#define LENGTH 65535
const int PLAYBACKFREQ = 44100;
const float PI2 = 3.14159265359f * 2;
const int freq1 = 697;
const int freq2 = 1209;



@implementation AudioPlayerViewController

@synthesize playButton, stopButton;

- (void)viewDidLoad {
    [super viewDidLoad];
 // Allocate space for an array with ten elements of type int.
int *ptr = malloc(SIZE * sizeof(int));
if (ptr == NULL) NSLog(@"Error: Memory buffer could not be allocated.");
else NSLog(@"Allocation succeeded.");

 // The formula for the tone, the content of the buffer.
for(int i=0; i<SIZE; i++) ptr[i] = (sin(i*(PI2*(PLAYBACKFREQ/freq1))) + sin(i*    (PI2*(PLAYBACKFREQ/freq2)))) * 16383;
NSData *myData = [[NSData alloc] initWithBytesNoCopy:ptr length:SIZE];
free(ptr);
ptr = NULL;
audioPlayer = [[AVAudioPlayer alloc] initWithData:myData error:&error];
audioPlayer.numberOfLoops = -1;
}
-(IBAction) playAudio: (id) sender {
    if (audioPlayer == nil) NSLog([error description]);             
    else [audioPlayer play];
}
-(IBAction) stopAudio: (id) sender { [audioPlayer stop]; }

- (void)dealloc {
    [audioPlayer release];
    [myData release];
    [super dealloc];
}

@end

在文档中，方法 initWithBytesNoCopy 的描述如下：

包含新对象数据的缓冲区。 bytes 必须指向用 malloc 分配的内存块。

所以我已经这样做了，但它不起作用。

任何形式的帮助将不胜感激！

原文

I want to generate a custom DTMF tone and play it on the iPhone.
In order to do so, I have created and allocated a memory buffer with a custom tone (ptr).
Now I want to create a NSData object, initialized with the memory buffer, and pass it to AVAudioPlayer using initWithData:error: instance method.

I wrote the following code, but when I press the button "Play", it crashes.

#import "AudioPlayerViewController.h"
#include <stdlib.h>
#include <math.h>
#define SIZE 10
#define LENGTH 65535
const int PLAYBACKFREQ = 44100;
const float PI2 = 3.14159265359f * 2;
const int freq1 = 697;
const int freq2 = 1209;



@implementation AudioPlayerViewController

@synthesize playButton, stopButton;

- (void)viewDidLoad {
    [super viewDidLoad];
 // Allocate space for an array with ten elements of type int.
int *ptr = malloc(SIZE * sizeof(int));
if (ptr == NULL) NSLog(@"Error: Memory buffer could not be allocated.");
else NSLog(@"Allocation succeeded.");

 // The formula for the tone, the content of the buffer.
for(int i=0; i<SIZE; i++) ptr[i] = (sin(i*(PI2*(PLAYBACKFREQ/freq1))) + sin(i*    (PI2*(PLAYBACKFREQ/freq2)))) * 16383;
NSData *myData = [[NSData alloc] initWithBytesNoCopy:ptr length:SIZE];
free(ptr);
ptr = NULL;
audioPlayer = [[AVAudioPlayer alloc] initWithData:myData error:&error];
audioPlayer.numberOfLoops = -1;
}
-(IBAction) playAudio: (id) sender {
    if (audioPlayer == nil) NSLog([error description]);             
    else [audioPlayer play];
}
-(IBAction) stopAudio: (id) sender { [audioPlayer stop]; }

- (void)dealloc {
    [audioPlayer release];
    [myData release];
    [super dealloc];
}

@end

In the documentation, the description of method initWithBytesNoCopy reads: