The SetPhoneLineVuMeterCallback procedure allows application software to receive full duplex digitally mixed audio sample block data from a phone line. This sample block data can be used for the purposes of driving VU meter display GUI elements in the VOIP application.
Note:
VU meter functionality shares the phone line's digital mixer that is used during phone call recording. You must configure the media engine to enable call recording if you want VU meter sample data. This does not mean that call recording has to be active during any call in order to get VU meter sampled data. It simply means the media engine's phone line record digital mixers must be created to support VU meter callback functionality.

Namespace:  LanScape
Assembly:  LMEVoipManaged (in LMEVoipManaged.dll) Version: 6.0.5226.26700

Syntax

C#
public VoipMediaEngine..::.TELEPHONY_RETURN_VALUE SetPhoneLineVuMeterCallback(
	VoipMediaEngine MediaEngine,
	int PhoneLine,
	VoipMediaEngine..::.PHONE_LINE_VU_METER_CALLBACK_PROC PhoneLineVuMeterCallback,
	Object UserData
)
Visual Basic (Declaration)
Public Function SetPhoneLineVuMeterCallback ( _
	MediaEngine As VoipMediaEngine, _
	PhoneLine As Integer, _
	PhoneLineVuMeterCallback As VoipMediaEngine..::.PHONE_LINE_VU_METER_CALLBACK_PROC, _
	UserData As Object _
) As VoipMediaEngine..::.TELEPHONY_RETURN_VALUE
Visual C++
public:
VoipMediaEngine..::.TELEPHONY_RETURN_VALUE SetPhoneLineVuMeterCallback(
	VoipMediaEngine^ MediaEngine, 
	int PhoneLine, 
	VoipMediaEngine..::.PHONE_LINE_VU_METER_CALLBACK_PROC^ PhoneLineVuMeterCallback, 
	Object^ UserData
)
J#
public VoipMediaEngine..::.TELEPHONY_RETURN_VALUE SetPhoneLineVuMeterCallback(
	VoipMediaEngine MediaEngine,
	int PhoneLine,
	VoipMediaEngine..::.PHONE_LINE_VU_METER_CALLBACK_PROC PhoneLineVuMeterCallback,
	Object UserData
)

Parameters

MediaEngine
Type: LanScape..::.VoipMediaEngine
An instance of the media engine.
PhoneLine
Type: System..::.Int32
The zero based phone line that will have call VU metering enabled.
PhoneLineVuMeterCallback
Type: LanScape..::.VoipMediaEngine..::.PHONE_LINE_VU_METER_CALLBACK_PROC
This callback procedure will be called whenever the media engine has a new recorded phone line sample block buffer. To disable VU meter callback capability, set this value to NULL when calling the SetPhoneLineVuMeterCallback API procedure.
UserData
Type: System..::.Object
A user supplied data value. This data value is passed to the PhoneLineVuMeterCallback procedure via the VoipMediaEngine..::.PHONE_LINE_VU_METER_DATA class.

Return Value

If the function succeeds, the return value will be SipSuccess.

If the function fails, the return value will be one of the following values as specified by the VoipMediaEngine..::.TELEPHONY_RETURN_VALUE data type.

Return ValueDescription
SipCallFailure
This value is returned by telephony API procedures to indicate general API failure. This error value is used as a "catch all error". If you receive this error, check to make sure that all parameters specified in the API procedure call are correct. Particularly, verify that pointers to memory regions are valid. This error return value is only used if a mapping to another specific error value does not exist.

(API return value)

SipInvalidHandle
Application software specified an invalid telephony handle in one of the API procedures. This usually indicates memory corruption on the part of application software.

(API return value)

SipBadPhoneLine
Application software called a telephony API procedure and specified an invalid phone line. Phone lines are numbered starting from zero. This error is most commonly returned when attempting to access phone lines in excess of the max number of lines supported by the telephony engine.

(API return value)

SipCallRecordNotEnabled
The media engine must be instantiated with call recording enabled before application software can call any of the phone line record API procedures. See the EnablePhoneLineRecording value of the VoipMediaEngine..::.START_SIP_TELEPHONY_PARAMS structure.

(API return value)

Remarks

None.

See Also