ACMDRVFORMATSUGGEST

This structure contains client-specified input arguments to the AcmFormatSuggest function. The ACM fills in this structure with the client’s input arguments and passes it to an ACM driver with an ACMDM_FORMAT_SUGGEST message.

Syntax

typedef struct {
DWORD cbStruct;
DWORD fdwSuggest;
LPWAVEFORMATEX pwfxSrc;
DWORD cbwfxSrc;
LPWAVEFORMATEX pwfxDst;
DWORD cbwfxDst;
} ACMDRVFORMATSUGGEST;

Members

cbStruct

Specifies the size, in bytes, of the ACMDRVFORMATSUGGEST structure.

fdwSuggest

Contains restriction flags that limit the possible destination formats; any combination of the following flags:

ACM_FORMATSUGGESTF_WFORMATTAG

The wFormatTag member of the WAVEFORMATEX structure pointed to by pwfxDst contains a format tag. The driver can only suggest a destination format associated with the specified format tag; it cannot enforce the suggested format.

ACM_FORMATSUGGESTF_NCHANNELS

The nChannels member of the WAVEFORMATEX structure pointed to by pwfxDst contains a channel value. The driver can only suggest a destination format whose channel value matches the specified value; it cannot enforce the suggested format.

ACM_FORMATSUGGESTF_NSAMPLESPERSEC

The nSamplesPerSec member of the WAVEFORMATEX structure pointed to by pwfxDst contains a sample rate. The driver can only suggest a destination format whose sample rate matches the specified rate; it cannot enforce the suggested format.

ACM_FORMATSUGGESTF_WBITSPERSAMPLE

The nBitsPerSample member of the WAVEFORMATEX structure pointed to by pwfxDst contains a sample size. The driver can only suggest a destination format whose sample size matches the specified size; it cannot enforce the suggested format.

pwfxSrc

Pointer to a WAVEFORMATEX structure describing the source format.

cbwfxSrc

Specifies the size, in bytes, of the WAVEFORMATEX structure pointed to by pwfxSrc.

pwfxDst

Pointer to a WAVEFORMATEX structure to receive the suggested destination format description. If flags in the fdwSuggest member are set, corresponding members of this structure contain client-specified values. The driver should fill in all empty structure members.

cbwfxDst

Specifies the size, in bytes, of the WAVEFORMATEX structure pointed to by pwfxDst. The driver cannot return an extended WAVEFORMATEX structure that is larger than this size.

Remarks

The WAVEFORMATEX structures specified for source or destination formats might be extended structures defined for particular formats. For example, see IMAADPCMWAVEFORMAT in the Mmreg.h header file. Check the structure’s wFormatTag member to determine the format type and, therefore, the specific structure being passed.

This structure is declared in the Msacmdrv.h header file.