acmFormatTagEnumCallback
The acmFormatTagEnumCallback
function specifies a callback function used with the acmFormatTagEnum function. The acmFormatTagEnumCallback
name is a placeholder for an application-defined function name.
BOOL ACMFORMATTAGENUMCB acmFormatTagEnumCallback(
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HACMDRIVERID hadid, |
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LPACMFORMATTAGDETAILS paftd, |
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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.
paftd
Address of an
ACMFORMATTAGDETAILS
structure that contains the enumerated format tag details.
dwInstance
Application-defined
value specified in the acmFormatTagEnum function.
fdwSupport
Driver-support
flags specific to the format tag. These flags are identical to the fdwSupport
flags of the ACMDRIVERDETAILS
structure. This parameter can be a combination of the following values and
indicates which operations the driver supports with the format tag:
ACMDRIVERDETAILS_SUPPORTF_ASYNC
Driver
supports asynchronous conversions with the specified filter tag.
ACMDRIVERDETAILS_SUPPORTF_CODEC
Driver
supports conversion between two different format tags where one of the tags is
the specified format tag. For example, if a driver supports compression from
WAVE_FORMAT_PCM to WAVE_FORMAT_ADPCM, this flag is set.
ACMDRIVERDETAILS_SUPPORTF_CONVERTER
Driver
supports conversion between two different formats of the specified format tag.
For example, if a driver supports resampling of WAVE_FORMAT_PCM, 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 the
specified format tag, this flag is set.
ACMDRIVERDETAILS_SUPPORTF_HARDWARE
Driver
supports hardware input, output, or both of the specified format tag through a
waveform-audio device. An application should use acmMetrics 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.
Return Values
The callback
function must return TRUE to continue enumeration or FALSE to stop enumeration.
Remarks
The acmFormatTagEnum
function will return MMSYSERR_NOERROR (zero) if no format tags 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