acmFilterEnumCallback
The acmFilterEnumCallback
function specifies a callback function used with the acmFilterEnum function. The
acmFilterEnumCallback name is a placeholder for an application-defined
function name.
BOOL ACMFILTERENUMCB acmFilterEnumCallback(
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HACMDRIVERID
hadid, |
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LPACMFILTERDETAILS pafd, |
|
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DWORD dwInstance, |
|
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DWORD fdwSupport |
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); |
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Parameters
hadid
Handle of the
ACM driver identifier.
pafd
Address of an
ACMFILTERDETAILS
structure that contains the enumerated filter details for a filter tag.
dwInstance
Application-defined
value specified in acmFilterEnum.
fdwSupport
Driver-support
flags specific to the driver identified by hadid for the specified
filter. These flags are identical to the fdwSupport flags of the ACMDRIVERDETAILS structure, but they are
specific to the filter that is being enumerated. This parameter can be a
combination of the following values and identifies which operations the driver
supports for the filter tag:
ACMDRIVERDETAILS_SUPPORTF_ASYNC
Driver
supports asynchronous conversions with the specified filter tag.
ACMDRIVERDETAILS_SUPPORTF_CODEC
Driver
supports conversion between two different format tags while using the specified
filter. For example, if a driver supports compression from WAVE_FORMAT_PCM to
WAVE_FORMAT_ADPCM with the specified filter, this flag is set.
ACMDRIVERDETAILS_SUPPORTF_CONVERTER
Driver
supports conversion between two different formats of the same format tag while
using the specified filter. For example, if a driver supports resampling of
WAVE_FORMAT_PCM with the specified filter, 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 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
indices to get the waveform-audio device identifiers associated with the
supporting ACM driver.
Return Values
The callback
function must return TRUE to continue enumeration or FALSE to stop enumeration.
Remarks
The acmFilterEnum
function will return MMSYSERR_NOERROR (zero) if no filters are to be
enumerated. Moreover, the callback function will not be called.
The following
functions should not be called from within the callback function: acmDriverAdd,
acmDriverRemove, and acmDriverPriority.
See Also