在Objective-C生成莫尔斯电码的风格色调

Question

我有一个类，将让我使用音频设备播放音，我希望能够做的是有类游戏莫尔斯电码的风格，当我发类短语或字母。

如何，我会去吗？我希望有人能指出我正确的方向。我已经包括音频发生器h和.m文件下面

// 
// Singer.h 
// musiculesdev 
// 
// Created by Dylan on 2/20/09. 
// Copyright 2009 __MyCompanyName__. All rights reserved. 
// 

#import <Foundation/Foundation.h> 
#import <AudioUnit/AudioUnit.h> 



@interface Singer : NSObject { 


    AudioComponentInstance audioUnit; 

} 


-(void)initAudio; // put this in init? 


-(void)start; 
-(void)stop; 
-(IBAction)turnOnSound:(id)sender; 

@end 


// 
// Singer.m 
// musiculesdev 
// 
// Created by Dylan on 2/20/09. 
// Copyright 2009 __MyCompanyName__. All rights reserved. 
// 

#import <AudioUnit/AudioUnit.h> 
#import <math.h> 

#import "Singer.h" 

#define kOutputBus 0 
#define kSampleRate 44100 
//44100.0f 
#define kWaveform (M_PI * 2.0f/kSampleRate) 


@implementation Singer 


OSStatus playbackCallback(void *inRefCon, 
          AudioUnitRenderActionFlags *ioActionFlags, 
          const AudioTimeStamp *inTimeStamp, 
          UInt32 inBusNumber, 
          UInt32 inNumberFrames, 
          AudioBufferList *ioData) {  

    //Singer *me = (Singer *)inRefCon; 

    static int phase = 0; 

    for(UInt32 i = 0; i < ioData->mNumberBuffers; i++) { 

     int samples = ioData->mBuffers[i].mDataByteSize/sizeof(SInt16); 

     SInt16 values[samples]; 

     float waves; 

     for(int j = 0; j < samples; j++) { 


      waves = 0; 


      waves += sin(kWaveform * 261.63f * phase); 
      waves += sin(kWaveform * 120.0f * phase); 
      waves += sin(kWaveform * 1760.3f * phase); 
      waves += sin(kWaveform * 880.0f * phase);    

      waves *= 32500/4; // <--------- make sure to divide by how many waves you're stacking 

      values[j] = (SInt16)waves; 
      values[j] += values[j]<<16; 

      phase++; 

     } 

     memcpy(ioData->mBuffers[i].mData, values, samples * sizeof(SInt16)); 

    } 


    return noErr; 

} 

-(IBAction)turnOnSound:(id)sender { 
    Singer *singer = [[Singer alloc] init]; 

    [singer start]; 
} 


-(id)init { 
    NSLog(@"In the singer init!!"); 
    if(self = [super init]) { 

     [self initAudio]; 

    } 

    return self; 

} 

-(void)initAudio { 

    OSStatus status; 

    AudioComponentDescription desc; 
    desc.componentType = kAudioUnitType_Output; 
    desc.componentSubType = kAudioUnitSubType_RemoteIO; 
    desc.componentFlags = 0; 
    desc.componentFlagsMask = 0; 
    desc.componentManufacturer = kAudioUnitManufacturer_Apple; 

    AudioComponent outputComponent = AudioComponentFindNext(NULL, &desc); 

    status = AudioComponentInstanceNew(outputComponent, &audioUnit); 

    UInt32 flag = 1; 
    status = AudioUnitSetProperty(audioUnit, kAudioOutputUnitProperty_EnableIO, kAudioUnitScope_Output, kOutputBus, &flag, sizeof(flag)); 

    AudioStreamBasicDescription audioFormat; 
    audioFormat.mSampleRate = kSampleRate; 
    audioFormat.mFormatID = kAudioFormatLinearPCM; 
    audioFormat.mFormatFlags = kAudioFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked; 
    audioFormat.mFramesPerPacket = 1; 
    audioFormat.mChannelsPerFrame = 1; 
    audioFormat.mBitsPerChannel = 16; 
    audioFormat.mBytesPerPacket = 2; 
    audioFormat.mBytesPerFrame = 2; 

    status = AudioUnitSetProperty(audioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Input, kOutputBus, &audioFormat, sizeof(audioFormat)); 

    AURenderCallbackStruct callbackStruct; 
    callbackStruct.inputProc = playbackCallback; 
    callbackStruct.inputProcRefCon = self; 

    status = AudioUnitSetProperty(audioUnit, kAudioUnitProperty_SetRenderCallback, kAudioUnitScope_Global, kOutputBus, &callbackStruct, sizeof(callbackStruct)); 

    status = AudioUnitInitialize(audioUnit); 

} 

-(void)start { 

    OSStatus status; 

    status = AudioOutputUnitStart(audioUnit); 

} 

-(void)stop { 

    OSStatus status; 

    status = AudioOutputUnitStop(audioUnit); 

} 

-(void)dealloc { 

    AudioUnitUninitialize(audioUnit); 

    [super dealloc]; 

} 

@end 

Answer 1

你需要能够生成特定时间的色调，通过特定时间的沉默分开。只要你有这两个积木，你可以发送莫尔斯电码：

dot = 1 unit 
dash = 3 units 
space between dots/dashes within a letter = 1 unit 
space between letters = 3 units 
space between words = 5 units 

的unit的长度决定了莫尔斯电码的整体速度。从例如50毫秒。

音调应该只是在适当的频率，例如纯正弦波400赫兹。沉默可以是一个包含所有零的备用缓冲区。这样，你可以“玩”无论是色调，并使用相同的API沉默，而不用担心定时/同步等