ACMFILTERTAGDETAILS structure

The ACMFILTERTAGDETAILS structure details a waveform-audio filter tag for an ACM filter driver.

Syntax

typedef struct tACMFILTERTAGDETAILS {
  DWORD cbStruct;
  DWORD dwFilterTagIndex;
  DWORD dwFilterTag;
  DWORD cbFilterSize;
  DWORD fdwSupport;
  DWORD cStandardFilters;
  char  szFilterTag[ACMFILTERTAGDETAILS_FILTERTAG_CHARS];
} ACMFILTERTAGDETAILS, *PACMFILTERTAGDETAILS, *LPACMFILTERTAGDETAILS;

Members

cbStruct

Size, in bytes, of the ACMFILTERTAGDETAILS structure. This member must be initialized before an application calls the acmFilterTagDetails or acmFilterTagEnum function. The size specified in this member must be large enough to contain the base ACMFILTERTAGDETAILS structure. When the acmFilterTagDetails function returns, this member contains the actual size of the information returned. The returned information will never exceed the requested size.

dwFilterTagIndex

Index of the filter tag to retrieve details for. The index ranges from zero to one less than the number of filter tags supported by an ACM driver. The number of filter tags supported by a driver is contained in the cFilterTags member of the ACMDRIVERDETAILS structure. The dwFilterTagIndex member is used only when querying filter tag details about a driver by index; otherwise, this member should be zero.

dwFilterTag

Waveform-audio filter tag that the ACMFILTERTAGDETAILS structure describes. This member is used as an input for the ACM_FILTERTAGDETAILSF_FILTERTAG and ACM_FILTERTAGDETAILSF_LARGESTSIZE query flags. This member is always returned if the acmFilterTagDetails function is successful. This member should be set to WAVE_FILTER_UNKNOWN for all other query flags.

cbFilterSize

Largest total size, in bytes, of a waveform-audio filter of the dwFilterTag type. For example, this member will be 40 for WAVE_FILTER_ECHO and 36 for WAVE_FILTER_VOLUME.

fdwSupport

Driver-support flags specific to the filter tag. These flags are identical to the fdwSupport flags of the ACMDRIVERDETAILS structure. This member can be a combination of the following values and identifies which operations the driver supports with the filter tag:

Name Description
ACMDRIVERDETAILS_SUPPORTF_ASYNC
Driver supports asynchronous conversions.
ACMDRIVERDETAILS_SUPPORTF_CODEC
Driver supports conversion between two different format tags while using the specified filter tag. For example, if a driver supports compression from WAVE_FORMAT_PCM to WAVE_FORMAT_ADPCM with the specified filter tag, this flag is set.
ACMDRIVERDETAILS_SUPPORTF_CONVERTER
Driver supports conversion between two different formats of the same format tag while using the specified filter tag. For example, if a driver supports resampling of WAVE_FORMAT_PCM with the specified filter tag, this flag is set.
ACMDRIVERDETAILS_SUPPORTF_FILTER
Driver supports a filter (modification of the data without changing any of the format attributes). For example, if a driver supports volume or echo operations on WAVE_FORMAT_PCM, this flag is set.
ACMDRIVERDETAILS_SUPPORTF_HARDWARE
Driver supports hardware input, output, or both with the specified filter tag through a waveform-audio device. An application should use the acmMetrics function with the ACM_METRIC_HARDWARE_WAVE_INPUT and ACM_METRIC_HARDWARE_WAVE_OUTPUT metric indexes to get the waveform-audio device identifiers associated with the supporting ACM driver.

cStandardFilters

Number of standard filters of the dwFilterTag type (that is, the combination of all filter characteristics). This value cannot specify all filters supported by the driver.

szFilterTag

String that describes the dwFilterTag type. This string is always returned if the acmFilterTagDetails function is successful.

Requirements

   
Minimum supported client Windows 2000 Professional [desktop apps only]
Minimum supported server Windows 2000 Server [desktop apps only]
Header msacm.h

See Also

ACMDRIVERDETAILS

Audio Compression Manager

Audio Compression Structures

acmFilterTagDetails

acmFilterTagEnum