LINEMEDIACONTROLTONE

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.

typedef struct linemediacontroltone_tag {

DWORD dwAppSpecific;

DWORD dwDuration;

DWORD dwFrequency1;

DWORD dwFrequency2;

DWORD dwFrequency3;

DWORD dwMediaControl;

} LINEMEDIACONTROLTONE, FAR *LPLINEMEDIACONTROLTONE;

Members
dwAppSpecific

This field is used by the application for tagging the tone. When this tone is detected, the value of the dwAppSpecific field is passed back to the application.

dwDuration

The duration in milliseconds during which the tone should be present before a detection is made.

dwFrequency1

dwFrequency2

dwFrequency3

The frequency in Hertz of a component of the tone. If fewer than three frequencies are needed in the tone, a value of zero 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

The media-control action. This field uses the following LINEMEDIACONTROL_ constants:

LINEMEDIACONTROL_NONE

No change is to be made to the media stream.

LINEMEDIACONTROL_RESET

Reset the media stream. Equivalent to an end-of-input. All buffers are released.

LINEMEDIACONTROL_PAUSE

Temporarily pause the media stream.

LINEMEDIACONTROL_RESUME

Start or resume a paused media stream.

LINEMEDIACONTROL_RATEUP

The speed of the media stream is increased by some stream-defined quantity.

LINEMEDIACONTROL_RATEDOWN

The speed of the media stream is decreased by some stream-defined quantity.

LINEMEDIACONTROL_RATENORMAL

The speed of the media stream is returned to normal.

LINEMEDIACONTROL_VOLUMEUP

The amplitude of the media stream is increased by some stream-defined quantity.

LINEMEDIACONTROL_VOLUMEDOWN

The amplitude of the media stream is decreased by some stream-defined quantity.

LINEMEDIACONTROL_VOLUMENORMAL

The amplitude of the media stream is returned to normal.

Remarks
No extensions.

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-mode changes for a given call. When a change to a listed media mode 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.