一个网络语音发送的问题

你也做局域网的语音通讯吗？用ACM是可以压缩，见下面的代码。但是噪音很大，不知如何消噪？？
include <windows.h>
#include <mmsystem.h>
#include <mmreg.h> // Multimedia registration
#include <msacm.h> // Audio Compression Manager
#include <stdio.h>
#include <math.h>// Locate a driver that supports a given format and return its ID
typedef struct {
HACMDRIVERID hadid;
WORD wFormatTag;
} FIND_DRIVER_INFO;
// callback function for format enumeration
BOOL CALLBACK find_format_enum(HACMDRIVERID hadid, LPACMFORMATDETAILS pafd, DWORD dwInstance, DWORD fdwSupport)
{FIND_DRIVER_INFO* pdi = (FIND_DRIVER_INFO*) dwInstance;
if (pafd->dwFormatTag == (DWORD)pdi->wFormatTag) {
// found it
pdi->hadid = hadid;
printf(" %4.4lXH, %s\n", pafd->dwFormatTag, pafd->szFormat);
return FALSE; // stop enumerating
}
//printf(" FORMAT not MATCH.\n");
return TRUE; // continue enumerating
}// callback function for driver enumeration
BOOL CALLBACK find_driver_enum(HACMDRIVERID hadid, DWORD dwInstance, DWORD fdwSupport)
{FIND_DRIVER_INFO* pdi = (FIND_DRIVER_INFO*) dwInstance;// open the driver
HACMDRIVER had = NULL;
HRESULT mmr = acmDriverOpen(&had, hadid, 0);
if (mmr) {// some error
return FALSE; // stop enumerating}// enumerate the formats it supports
DWORD dwSize = 0;
mmr = acmMetrics(had, ACM_METRIC_MAX_SIZE_FORMAT, &dwSize);
if (dwSize < sizeof(WAVEFORMATEX)) dwSize = sizeof(WAVEFORMATEX); // for MS-PCM
WAVEFORMATEX* pwf = (WAVEFORMATEX*) malloc(dwSize);
memset(pwf, 0, dwSize);
pwf->cbSize = LOWORD(dwSize) - sizeof(WAVEFORMATEX);
pwf->wFormatTag = pdi->wFormatTag;
ACMFORMATDETAILS fd;
memset(&fd, 0, sizeof(fd));
fd.cbStruct = sizeof(fd);
fd.pwfx = pwf;
fd.cbwfx = dwSize;
fd.dwFormatTag = pdi->wFormatTag;
mmr = acmFormatEnum(had, &fd, find_format_enum, (DWORD)(VOID*)pdi, 0);
free(pwf);
acmDriverClose(had, 0);
if (pdi->hadid || mmr) {
// found it or some error
return FALSE; // stop enumerating
}return TRUE; // continue enumeration
}// locate the first driver that supports a given format tag
HACMDRIVERID find_driver(WORD wFormatTag)
{
FIND_DRIVER_INFO fdi;
fdi.hadid = NULL;
fdi.wFormatTag = wFormatTag;
MMRESULT mmr = acmDriverEnum(find_driver_enum, (DWORD)(VOID*)&fdi, 0);
if (mmr) return NULL;
return fdi.hadid;
}// get a description of the first format supported for a given tag
WAVEFORMATEX* get_driver_format(HACMDRIVERID hadid, WORD wFormatTag)
{
// open the driver
HACMDRIVER had = NULL;
MMRESULT mmr = acmDriverOpen(&had, hadid, 0);
if (mmr) {
return NULL;
}// allocate a structure for the info
DWORD dwSize = 0;
mmr = acmMetrics(had, ACM_METRIC_MAX_SIZE_FORMAT, &dwSize);
if (dwSize < sizeof(WAVEFORMATEX)) dwSize = sizeof(WAVEFORMATEX); // for MS-PCM
WAVEFORMATEX* pwf = (WAVEFORMATEX*) malloc(dwSize);
memset(pwf, 0, dwSize);
pwf->cbSize = LOWORD(dwSize) - sizeof(WAVEFORMATEX);
pwf->wFormatTag = wFormatTag;ACMFORMATDETAILS fd;
memset(&fd, 0, sizeof(fd));
fd.cbStruct = sizeof(fd);
fd.pwfx = pwf;
fd.cbwfx = dwSize;
fd.dwFormatTag = wFormatTag;// set up a struct to control the enumeration
FIND_DRIVER_INFO fdi;
fdi.hadid = NULL;
fdi.wFormatTag = wFormatTag;mmr = acmFormatEnum(had, &fd, find_format_enum, (DWORD)(VOID*)&fdi, 0);
acmDriverClose(had, 0);
if ((fdi.hadid == NULL) || mmr) {
free(pwf);
return NULL;
}return pwf;
}
int main(int argc, char* argv[])
{
// First we create a wave that might have been just recorded.
// The format is 11.025 kHz, 8 bit mono PCM which is a recording
// format available on all machines.
// our sample wave will be 1 second long and will be a sine wave
// of 1kHz which is exactly 1,000 cyclesWAVEFORMATEX wfSrc;
memset(&wfSrc, 0, sizeof(wfSrc));
wfSrc.cbSize = 0;
wfSrc.wFormatTag = WAVE_FORMAT_PCM; // pcm
wfSrc.nChannels = 1; // mono
wfSrc.nSamplesPerSec = 8000; // 11.025 kHz
wfSrc.wBitsPerSample = 16;// 8 bit
wfSrc.nBlockAlign = wfSrc.nChannels * wfSrc.wBitsPerSample / 8;
wfSrc.nAvgBytesPerSec = wfSrc.nSamplesPerSec * wfSrc.nBlockAlign;
DWORD dwSrcSamples = wfSrc.nSamplesPerSec;
DWORD dwSrcBytes = wfSrc.nAvgBytesPerSec;
unsigned char pSrcData[22050]; // 1 second durationdouble f = 1000.0;
double pi = 4.0 * atan(1.0);
double w = 2.0 * pi * f;
for (DWORD dw = 0; dw < dwSrcBytes; dw++) {
double t = (double) dw / (double) wfSrc.nSamplesPerSec;
pSrcData[dw] = 128 + (unsigned char)(127.0 * sin(w * t));
}// Select a format to convert to
// WORD wFormatTag = WAVE_FORMAT_ADPCM;
// WORD wFormatTag = WAVE_FORMAT_IMA_ADPCM;
// WORD wFormatTag = WAVE_FORMAT_GSM610;
// WORD wFormatTag = WAVE_FORMAT_ALAW;
// WORD wFormatTag = WAVE_FORMAT_MULAW;
// WORD wFormatTag = 0x32; // MSN
// WORD wFormatTag = WAVE_FORMAT_DSPGROUP_TRUESPEECH;
WORD wFormatTag = 0x42; // G.723.1// Now we locate a CODEC that supports the destination format tag
HACMDRIVERID hadid = find_driver(wFormatTag);
if (hadid == NULL) {
printf("No driver found\n");
exit(1);
}
printf("Driver found (hadid: %4.4lXH)\n", hadid);
// get the details of the format
// Note: this is just the first of one or more possible formats for the given tag
//WAVEFORMATEX* pwfDrv = get_driver_format(hadid, wFormatTag);
WAVEFORMATEX* pwfDrv;
pwfDrv = (WAVEFORMATEX*)new char[28];
pwfDrv->wFormatTag = 66;
pwfDrv->nChannels = 1;
pwfDrv->nSamplesPerSec = 8000;
pwfDrv->nAvgBytesPerSec = 800;
pwfDrv->nBlockAlign = 24;
pwfDrv->wBitsPerSample = 0;
pwfDrv->cbSize = 10;
unsigned char extra[10] ={ 2, 0, 0xce, 0x9a, 0x32, 0xf7, 0xa2, 0xae, 0xde, 0xac };
for(int i=0;i<pwfDrv->cbSize;i++)
*((unsigned char *)pwfDrv+18+i) = extra[i];for(i=0;i<28;i++)
printf("%d,",*((unsigned char *)pwfDrv+i));if (pwfDrv == NULL) {
printf("Error getting format info\n");
exit(1);
}
printf("Driver format: %u bits, %lu samples per second\n", pwfDrv->wBitsPerSample, pwfDrv->nSamplesPerSec);///////////////////////////////////////////////////////////////////////////////////
// convert the intermediate PCM format to the final format// open the driver
HACMDRIVER had = NULL;
MMRESULT mmr;
mmr = acmDriverOpen(&had, hadid, 0);
if (mmr) {
printf("Failed to open driver\n");
exit(1);
}// open the conversion stream
// Note the use of the ACM_STREAMOPENF_NONREALTIME flag. Without this
// some software compressors will report error 512 - not possible
HACMSTREAM hstr1;
HACMSTREAM hstr2;
mmr = acmStreamOpen(&hstr1,
had, // driver handle
&wfSrc, // source format
pwfDrv, // destination format
NULL, // no filter
NULL, // no callback
0, // instance data (not used)
0);//ACM_STREAMOPENF_NONREALTIME); // flags
if (mmr) {
printf("Failed to open a stream to do PCM to driver format conversion\n");
exit(1);
}
mmr = acmStreamOpen(&hstr2,
had, // driver handle
pwfDrv, // source format
&wfSrc,// destination format
NULL, // no filter
NULL, // no callback
0, // instance data (not used)
0);//ACM_STREAMOPENF_NONREALTIME); // flags
if (mmr) {
printf("Failed to open a stream to do PCM to driver format conversion\n");
exit(1);
}// allocate a buffer for the result of the conversion.
// compute the output buffer size based on the average byte rate
// and add a bit for randomness
// the IMA_ADPCM driver fails the conversion without this extra space
DWORD dwDstBytes = pwfDrv->nAvgBytesPerSec * dwSrcSamples / wfSrc.nSamplesPerSec;
dwDstBytes = dwDstBytes ; // add a little room
unsigned char pDstData[800];//#ifdef _DEBUG
// fill the dest buffer with zeroes just so we can see if anything got
// converted in the debugger
memset(pDstData, 0, dwDstBytes);
//#endif// fill in the conversion info
ACMSTREAMHEADER strhdr1;
ACMSTREAMHEADER strhdr2;
memset(&strhdr1, 0, sizeof(strhdr1));
strhdr1.cbStruct = sizeof(strhdr1);
strhdr1.pbSrc = pSrcData; // the source data to convert
strhdr1.cbSrcLength = dwSrcBytes;
strhdr1.pbDst = pDstData;
strhdr1.cbDstLength = dwDstBytes;// prep the header
mmr = acmStreamPrepareHeader(hstr1, &strhdr1, 0); // convert the data
mmr = acmStreamConvert(hstr1, &strhdr1, 0);
if (mmr) {
printf("Failed to do PCM to driver format conversion\n");
exit(1);
}printf("Converted OK\n");printf("Source wave had %lu bytes\n", dwSrcBytes);
printf("Converted wave has %lu bytes\n", strhdr1.cbDstLengthUsed);
printf("Compression ratio is %f\n", (double) dwSrcBytes / (double) strhdr1.cbDstLengthUsed);
memset(&strhdr2, 0, sizeof(strhdr2));
strhdr2.cbStruct = sizeof(strhdr2);
strhdr2.pbSrc = pDstData; // the source data to convert
strhdr2.cbSrcLength = dwDstBytes;
strhdr2.pbDst = pSrcData;
strhdr2.cbDstLength = dwSrcBytes;// prep the header
mmr = acmStreamPrepareHeader(hstr2, &strhdr2, 0); // convert the data
mmr = acmStreamConvert(hstr2, &strhdr2, 0);
if (mmr) {
printf("Failed to do driver to PCM format conversion\n");
exit(1);
}
printf("Converted 2 OK\n");
mmr = acmStreamUnprepareHeader(hstr1, &strhdr1, 0);
// mmr = acmStreamUnprepareHeader(hstr2, &strhdr2, 0);
// close the stream and driver
mmr = acmStreamClose(hstr1, 0);
mmr = acmStreamClose(hstr2, 0);
mmr = acmDriverClose(had, 0);// show the conversion stats
printf("Source wave had %lu bytes\n", dwDstBytes);
printf("Converted wave has %lu bytes\n", strhdr2.cbDstLengthUsed);
printf("Compression ratio is %f\n", (double) dwDstBytes / (double) strhdr2.cbDstLengthUsed); getchar();return 0;
}
我觉得局域网中如果传输8KH,单声道，8位的声音数据不用压缩也可以，一秒钟总共才传输8k的数据。

调试易

一个网络语音发送的问题

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