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没问题，但我会接受建议=]
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here的代码来获取麦克风输入并将其回显给扬声器。
这样可以正常工作，但在捕获完成后我似乎无法播放完全捕获的音频。
当捕捉到某些声音时，我将其存储在如此列表中......
for (int i = 0; i < CAP_SIZE; i++)
{
playbackBuffer.push_back( buffer[i] );
}
然后在捕获完成后我尝试（并且失败）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));
调试时我可以看到playbackBuffer里面有很多数据，此时播放的噪音有一瞬间，但远不及捕获的噪音。
编辑：我添加了一行
alGenBuffers(1, &tempPlayback);
创建tempPlayback之后和调用alBufferData（...）之前，现在播放的时间正确，但我听到的只是一个高音调的噪音。
答案 0 :(得分：5)
这是一个非常简单的程序，可以捕获5秒的音频， 暂停，然后再捕获5秒钟的音频，最后播放所有音频 回来（我用它来调试捕获一次的问题）。
它适用于薄荷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);
}
编译：
g++ p.cpp -lalut -lopenal -o p
答案 1 :(得分：0)
// 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;
}
答案 2 :(得分：0)
我能用麦克风录制的唯一节目 在网上找到你开始使用的那个和我发给你的那个。 我有点朝着你的方向前进。我发给你的代码就是那个 我想修改。我从stackoverflow开始。 我用扭曲的BASIC编程语言找到了我们想要的代码， 但我不是一个好语言。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