OpenAL播放捕获的音频数据c ++

Posted 2023-02-25

【中文标题】OpenAL播放捕获的音频数据c ++

【英文标题】：OpenAL playback captured audio data c++

【发布时间】：2012-03-27 09:24:25

【问题描述】：

我正在尝试使用 OpenAL 创建语音聊天程序。事情的网络方面似乎还可以，但我会就此提出建议=]

我目前遇到的问题是尝试从麦克风播放捕获的音频数据。 我按照找到的代码 here 获取麦克风输入并将其回显到扬声器。

这工作正常，但在捕获完成后我似乎无法播放完全捕获的音频。

当一些声音被捕获时，我将它存储在一个列表中......

for (int i = 0; i < CAP_SIZE; i++)

    playbackBuffer.push_back( buffer[i] );

然后在捕获完成后，我尝试（但失败）使用以下代码播放该音频

ALuint  playbackSource;
alGenSources(1, &playbackSource);
errorCode = alGetError();

ALuint tempPlayback;
alBufferData(tempPlayback, AL_FORMAT_MONO16, &playbackBuffer.front(), playbackBuffer.size()*sizeof(ALuint), FREQ);

// Attach the playback buffer to the new playback source
alSourcei(playbackSource, AL_BUFFER, tempPlayback);
alSourcePlay(playbackSource);

ALint sState = 0;
do

    alGetSourcei(playbackSource, AL_SOURCE_STATE, &sState);

while ((sState == AL_PLAYING));

在调试时，我可以看到playbackBuffer 中有很多数据，并且此时播放了一瞬间的噪音，但与捕获的噪音相去甚远。

编辑：我已添加该行

alGenBuffers(1, &tempPlayback);

在创建 tempPlayback 之后和调用 alBufferData(...) 之前，现在播放正确的时间，但我听到的只是整个过程中的高音。

【参考方案1】：

这是一个非常简单的程序，可以捕获 5 秒的音频， 暂停，然后再捕捉 5 秒的音频，最后全部播放 返回（我用它来调试一次捕获问题）。

它适用于 mint 13 linux 笔记本电脑。 Mint 就像 ubuntu 12.04

#include <stdio.h> 
#include <stdlib.h> 
#include <string.h> 
#include <unistd.h>
#include <AL/al.h> 
#include <AL/alc.h> 
#include <sys/time.h>
#include <ctime> 

int main(void) 
 
const ALCchar *   devices; 
const ALCchar *         ptr; 
ALCdevice *       mainDev; 
ALCcontext *      mainContext; 
ALCdevice *       captureDev; 
ALubyte           captureBuffer[1048576]; 
ALubyte           *captureBufPtr; 
ALint             samplesAvailable; 
ALint             samplesCaptured; 
time_t            currentTime; 
time_t            lastTime; 
ALuint            buffer; 
ALuint            source; 
ALint             playState; 
int               i; 

// Print the list of capture devices 
printf("Available playback devices:\n");

devices = alcGetString(NULL, ALC_DEVICE_SPECIFIER); 
ptr = devices; 
//while (ptr[0] != NULL)
while (*ptr)
 
   printf("   %s\n", ptr); 
   ptr += strlen(ptr) + 1; 
 

// Open a playback device and create a context first 
printf("Opening playback device:\n"); 
mainDev = alcOpenDevice(NULL); 
if (mainDev == NULL) 
 
  printf("Unable to open playback device!\n"); 
  exit(1); 
 
devices = alcGetString(mainDev, ALC_DEVICE_SPECIFIER); 
printf("   opened device '%s'\n", devices); 
mainContext = alcCreateContext(mainDev, NULL); 
if (mainContext == NULL) 
 
  printf("Unable to create playback context!\n"); 
  exit(1); 
 
printf("   created playback context\n"); 

// Make the playback context current 
alcMakeContextCurrent(mainContext); 
alcProcessContext(mainContext); 

// Print the list of capture devices 

printf("Available capture devices:\n"); 
devices = alcGetString(NULL, ALC_CAPTURE_DEVICE_SPECIFIER); 
ptr = devices; 

//while (ptr[0] != NULL)
while (*ptr)
 
   printf("   %s\n", ptr); 
   ptr += strlen(ptr) + 1; 


// Open the default device 
printf("Opening capture device:\n"); 
captureDev = alcCaptureOpenDevice(NULL, 8000, AL_FORMAT_MONO16, 800); 
if (captureDev == NULL) 
  
  printf("   Unable to open device!\n"); 
  exit(1); 
 
devices = alcGetString(captureDev, ALC_CAPTURE_DEVICE_SPECIFIER); 
printf("   opened device %s\n", devices); 

// Wait for three seconds to prompt the user 
for (i = 3; i > 0; i--) 
 
  printf("Starting capture in %d...\r", i); 
  fflush(stdout); 
  lastTime = time(NULL); 
  currentTime = lastTime; 
  while (currentTime == lastTime) 
   
     currentTime = time(NULL); 
     usleep(100000); 
   
 

printf("Starting capture NOW!\n"); 
fflush(stdout); 
lastTime = currentTime; 

// Capture (roughly) five seconds of audio 
alcCaptureStart(captureDev); 
samplesCaptured = 0; 
captureBufPtr = captureBuffer; 
while (currentTime < (lastTime + 5)) 
 
  // Get the number of samples available 
  alcGetIntegerv(captureDev, ALC_CAPTURE_SAMPLES, 1, &samplesAvailable); 

  // Copy the samples to our capture buffer 
  if (samplesAvailable > 0) 
   
     alcCaptureSamples(captureDev, captureBufPtr, samplesAvailable); 
     samplesCaptured += samplesAvailable; 
     printf("Captured %d samples (adding %d)\r", samplesCaptured, 
        samplesAvailable); 
     fflush(stdout); 

     // Advance the buffer (two bytes per sample * number of samples) 
     captureBufPtr += samplesAvailable * 2; 
   

  // Wait for a bit 
  usleep(10000); 

  // Update the clock 
  currentTime = time(NULL); 
 
printf("\nPausing capture.\n"); 
alcCaptureStop(captureDev); 

// Wait for three seconds to prompt the user 
for (i = 3; i > 0; i--) 
 
  printf("Resuming capture in %d...\r", i); 
  fflush(stdout); 
  lastTime = time(NULL); 
  currentTime = lastTime; 
  while (currentTime == lastTime) 
   
     currentTime = time(NULL); 
     usleep(100000); 
   
 

printf("Resuming capture NOW!\n"); 
fflush(stdout); 
lastTime = currentTime; 

// Capture (roughly) five seconds of audio 
alcCaptureStart(captureDev); 
while (currentTime < (lastTime + 5)) 
 
  // Get the number of samples available 
  alcGetIntegerv(captureDev, ALC_CAPTURE_SAMPLES, 1, &samplesAvailable); 

  // Copy the samples to our capture buffer 
  if (samplesAvailable > 0) 
   
     alcCaptureSamples(captureDev, captureBufPtr, samplesAvailable); 
     samplesCaptured += samplesAvailable; 
     printf("Captured %d samples (adding %d)\r", samplesCaptured, 
        samplesAvailable); 
     fflush(stdout); 

     // Advance the buffer (two bytes per sample * number of samples) 
     captureBufPtr += samplesAvailable * 2; 
   

  // Wait for a bit 
  usleep(10000); 

  // Update the clock 
  currentTime = time(NULL); 
 

printf("\nDone capturing.\n"); 
alcCaptureStop(captureDev); 

// Play back the captured data 
printf("Starting playback...\n"); 
fflush(stdout); 

// Generate an OpenAL buffer for the captured data 
alGenBuffers(1, &buffer); 
alGenSources(1, &source); 
alBufferData(buffer, AL_FORMAT_MONO16, captureBuffer,samplesCaptured*2, 8000); 
alSourcei(source, AL_BUFFER, buffer); 
alSourcePlay(source); 

// Wait for the source to stop playing 
playState = AL_PLAYING; 
while (playState == AL_PLAYING) 
 
  printf("  source %d is playing...\r", source); 
  fflush(stdout); 
  alGetSourcei(source, AL_SOURCE_STATE, &playState); 
  usleep(100000); 
 
printf("\nDone with playback.\n"); 
fflush(stdout); 

// Shut down OpenAL 
alDeleteSources(1, &source); 
alDeleteBuffers(1, &buffer); 
alcMakeContextCurrent(NULL); 
alcCloseDevice(mainDev); 
alcCaptureCloseDevice(captureDev); 

用这个编译：

g++ p.cpp -lalut -lopenal -o p

【参考方案2】：

// Compile as: g++ p.cpp -lalut -lopenal -o p
//runs on ubuntu linux for around 2 seconds
#include <AL/al.h>    // OpenAL header files
#include <AL/alc.h>

//#include "stdafx.h"
#include <iostream>
#include <stdio.h>
//#include <windows.h>
//#include <al.h>
//#include <alc.h>


using namespace std;
int main()





ALCdevice *dev[2];
ALCcontext *ctx;
ALuint source, buffers[3];
char data[5000];
ALuint buf;
ALint val;

    float ttotal;
    unsigned int ccount;
    long int c1ount;
    c1ount =0;

dev[0] = alcOpenDevice(NULL);
ctx = alcCreateContext(dev[0], NULL);
alcMakeContextCurrent(ctx);

alGenSources(1, &source);
alGenBuffers(3, buffers);

/* Setup some initial silent data to play out of the source */
alBufferData(buffers[0], AL_FORMAT_MONO16, data, sizeof(data), 22050);
alBufferData(buffers[1], AL_FORMAT_MONO16, data, sizeof(data), 22050);
alBufferData(buffers[2], AL_FORMAT_MONO16, data, sizeof(data), 22050);
alSourceQueueBuffers(source, 3, buffers);

/* If you don't need 3D spatialization, this should help processing time */
alDistanceModel(AL_NONE); 

dev[1] = alcCaptureOpenDevice(NULL, 22050, AL_FORMAT_MONO16, sizeof(data)/2); //22050 mean 22.050 samples per     second. or 44100 for 44.1 per second.

/* Start playback and capture, and enter the audio loop */
alSourcePlay(source);
alcCaptureStart(dev[1]);    //starts ring buffer

while(1) 

    /* Check if any queued buffers are finished */
    alGetSourcei(source, AL_BUFFERS_PROCESSED, &val);
    if(val <= 0)
        continue;

    /* Check how much audio data has been captured (note that 'val' is the
    * number of frames, not bytes) */
    alcGetIntegerv(dev[1], ALC_CAPTURE_SAMPLES, 1, &val);

    /* Read the captured audio */
    alcCaptureSamples(dev[1], data, val);


        //***** Process/filter captured data here *****//


c1ount = c1ount +1;
if(c1ount >= 33)
          break;
         


        //for (int ii=0;ii<val;++ii) 
        //  data[ii]*=0.1; // Make it quieter
        //
    //***** end Process/filter captured data here *****//

    /* Pop the oldest finished buffer, fill it with the new capture data,
    then re-queue it to play on the source */
    alSourceUnqueueBuffers(source, 1, &buf);
    alBufferData(buf, AL_FORMAT_MONO16, data, val*2 /* bytes here, not
    frames */, 22050);
    alSourceQueueBuffers(source, 1, &buf);

    /* Make sure the source is still playing */
    alGetSourcei(source, AL_SOURCE_STATE, &val);

    if(val != AL_PLAYING)
    

        alSourcePlay(source);
    


cout<< "fgggggggg\n";


/* Shutdown and cleanup */
alcCaptureStop(dev[1]);
alcCaptureCloseDevice(dev[1]);

alSourceStop(source);
alDeleteSources(1, &source);
alDeleteBuffers(3, buffers);
alDeleteBuffers(1, &buf);

alcMakeContextCurrent(NULL);
alcDestroyContext(ctx);
alcCloseDevice(dev[0]); 

return 0;

【讨论】：

感谢您的回复，但我觉得我可能没有正确解释自己。我在发布的链接中获得了代码，它在录制的同时播放声音，我需要存储录制的声音，然后在录制完成后播放。如前所述，这个项目的最终结果将是一个语音聊天风格的程序，所以我计划录制一段音频，通过网络发送该段，同时录制下一段，然后该段将在另一端播放。再次感谢您的帮助。

【参考方案3】：

我可以通过麦克风录制的唯一程序 在网上找到的是您开始使用的和我发送给您的。 我有点像你一样的方向。我发给你的代码就是那个 我正在尝试修改。我从***中得到它。 我用一种扭曲的 BASIC 编程语言找到了我们想要的代码， 但我的语言不好。链接是：

 http://www.blitzbasic.com/Community/posts.php?topic=90830

If you can get it to work that would be great. And even better, if it
could be change over to c/c++.

I have been looking for microphone capture programs for around two
years. Waiting for some thing simple to come along.
So now I am focusing on the these programs to figure how they work
with debugger and test subroutines figure out the dynamics of freealut.
because I do not see any thing simple comming along any time soon.
OpenAL is the only software I cold get to work.  the documentation
provided by Creative web site is good referance for some one who is
already an expert with the software.
I could not get FBOD, alas, SDL,  Allegro4, or OSS to work because
of a lack of working examples, or no good information.

Good luck.

   keghn

【讨论】：

没有设法让其中任何一个像我想要的那样工作 =\ 从好的方面来说，我已经设法使用 TeamSpeak 3 sdk link 得到一些工作，它处理捕获/网络/playback 非常好，文档也很有帮助。业余爱好者可以免费使用（不确定这是否涵盖您自己），但需要获得商业使用许可。