Type

Name

Description

ILMADetUserCallback

CallbackObj

(write-only) Set the callback object pointer.

If not NULL, the CallbackProc method of this interface will be called to report audio detection events.

Set to NULL (or to "Nothing" in VB) if you do not wish to receive notifications anymore. (For example, before you delete the callback object interface).

VARIANT_BOOL

Enable

Enable/Disable audio detection. Set to TRUE to enable audio detection and receive event notifications.

long

Threshold

The threshold (in dB) used to detect sound. The allowed range is –40 to 0.

–40 is equivalent to absolute silence and 0 is the loudest possible sound. All sounds below this threshold are considered silence.

You set this depending on your microphone. Usually, a value between–38 and –30 is used.

long

MinSilenceTime

The minimum length of silence periods (in milliseconds). Silences shorter than MinSilenceTime will be considered part of the sound. You want to set this value so short pauses do not trigger false silences. Most conversations contain short silences while the people talking draw their breath or pause while they are thinking.

long

LeftLevel

(read-only) The intensity (power) of the signal in the left channel (in dB).

Note: If the audio stream The portion of the file holding the audio data. The audio data might be compressed to save disk space. The data has to be decompressed using an audio decompressor oftware component which decompresses audio. It must be designed to work with ACM or DirectShow . Note that different compression methods require different decompressors. There is no universal decompressor capable of decoding all compressed streams. before you can play (hear) it. is mono, the values of LeftLevel and RightLevel are the same.

long

RightLevel

(read-only) The intensity (power) of the signal in the right channel (in dB).

Note: If the audio stream is mono, the values of LeftLevel and RightLevel are the same.

long

Interval

The time intervals at which the filter will check the stream for audio data. This value is in milliseconds.

long

Delay

The amount of time the filter waits before it starts checking the stream for sound data (sound detection). This value is in milliseconds.

VARIANT_BOOL

AutoStart

Flag that indicates whether to start sound detection when streaming starts or not. Set this to VARIANT_TRUE to have the filter start sound detection when streaming starts. Set this to VARIANT_FALSE to start sound detection manually. Please note that if the Delay property has been set, sound detection will not begin, regardless of the value of AutoStart, until the delay period has elapsed.

AudDetStateConstants

State

(read only) Indicates the state of audio detection. Possible values are:

AUDDET_STATE_RUNNING:  The filter is processing streaming data and the sound detection process has started.

AUDDET_STATE_STOPPED:  The filter is not processing streaming data and the sound detection process is not running.