有谁用MS的 ACM（Audio Compression Manager）进行过音频的采集和压缩呀？

[zxyin1]

最近在用VC进行音频压缩，感觉不是很好用，大家一般用什么来进行音频压缩呀？

提供经验者均有分！ ：）

[akiko]

ACM还可以的,这儿有篇详细介绍的:http://tzsvc.xiloo.com/skill/media/01.htm

[honglunxu]

关键找到合适的压缩算法
当然如果要用压缩工具的话，更简单了

[zxyin1]

up

[zxyin1]

ACM中如何获得指定驱动（Microsoft G.723.1 CODEC）的id而返回呢？没有人知道吗？

[akiko]

用find_driver试试

typedef struct {
HACMDRIVERID hadid;
WORD wFormatTag;
} FIND_DRIVER_INFO;

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;
return FALSE; // stop enumerating
}

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;
MMRESULT mmr = acmDriverOpen(&had, hadid, 0);
if (mmr) {

// some error
return FALSE; // stop enumerating

}

// enumerate the formats it supports
DWORD dwSize = 0;
mmr = acmMetrics((HACMOBJ)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
}

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;
}

[zxyin1]

如何获得指定驱动的ID（比方说格式为WORD wFormatTag = WAVE_FORMAT_G723_ADPCM;
的CODEC的id）呢？好像应该在回调函数DriverEnumProc中设定某种条件，然后返回0

[zxyin1]

啊，真是雪中送炭啊，感谢！