LINEMEDIACONTROLTONE structure (tapi.h)

The LINEMEDIACONTROLTONE structure describes a media action to be executed when a tone has been detected. It is used as an entry in an array. The lineSetMediaControl and TSPI_lineSetMediaControl functions use this structure.

Syntax

typedef struct linemediacontroltone_tag {
  DWORD dwAppSpecific;
  DWORD dwDuration;
  DWORD dwFrequency1;
  DWORD dwFrequency2;
  DWORD dwFrequency3;
  DWORD dwMediaControl;
} LINEMEDIACONTROLTONE, *LPLINEMEDIACONTROLTONE;

Members

dwAppSpecific

Used by the application for tagging the tone. When this tone is detected, the value of the dwAppSpecific member is passed back to the application.

dwDuration

Duration of time during which the tone should be present before a detection is made, in milliseconds.

dwFrequency1

First frequency of the tone, in hertz.

dwFrequency2

Second frequency of the tone, in hertz.

dwFrequency3

Third frequency of the tone, in hertz. If fewer than three frequencies are needed in the tone, a value of 0 should be used for the unused frequencies. A tone with all three frequencies set to zero is interpreted as silence and can be use for silence detection.

dwMediaControl

Media control action. This member uses one of the LINEMEDIACONTROL_ Constants.

Remarks

This structure may not be extended.

The LINEMEDIACONTROLTONE structure defines a tuple <tone, media-control action>. An array of these tuples is passed to the lineSetMediaControl function to set media control actions triggered by media type changes for a given call. When a change to a listed media type is detected, the corresponding action on the media stream is invoked.

A tone with all frequencies set to zero corresponds to silence. An application can thus monitor the call's information stream for silence.

Requirements

See also

TSPI_lineSetMediaControl

lineSetMediaControl