| Microsoft DirectX 8.0 |
IScanningTuner inherits from ITuner and permits direct control of a tuner that supports searching for valid programming. The client must provide a valid tuning space (via ITuner::put_TuningSpace or ITuner::put_TuneRequest) before calling any of the methods in this interface. This interface is meant to be used in conjunction with the ITunerEvents outbound interface.
MethodName Description ITuner Methods get_TuningSpace Gets the Tuning Space currently in effect for the tuner. put_TuningSpace Sets the Tuning Space currently in effect for the tuner. EnumTuningSpaces Creates an enumerator for the Tuning Spaces preferred by this implementation. get_TuneRequest Gets the Tune Request currently in effect for the tuner. put_TuneRequest Sets the Tune Request currently in effect for the tuner. Validate Returns a value indicating that the Tune Request can be carried out. get_PreferredComponentTypes Gets the collection of ComponentType objects used for default component selection. put_PreferredComponentTypes Sets the collection of ComponentType objects used for default component selection. get_SignalStrength Retrieves the tuner-specific signal strength metric. TriggerSignalEvents Puts the tuner into a mode where ISignalEvents::OnSignal will be repeatedly called. IScanningTuner Methods SeekUp Changes the channel to the next higher channel with valid programming. SeekDown Changes the channel to the next lower channel with valid programming. ScanUp Changes the channel to the next higher channel with valid programming, pauses for the specified number of milliseconds, then repeats until canceled. ScanDown Changes the channel to the next lower channel with valid programming, pauses for the specified number of milliseconds, then repeats… until canceled. AutoProgram Scans for all channels with valid programming.
Changes the channel to the next higher channel with valid programming.
Syntax
HRESULT SeekUp();
Return Value
Returns S_OK if successful. If the method fails, error information can be retrieved using the standard COM IErrorInfo interface.
Remarks
This method returns immediately, and the seek continues in the background. The seek can be canceled by calling any other tuning operation.
Changes the channel to the next lower channel with valid programming.
Syntax
HRESULT SeekDown();
Return Value
Returns S_OK if successful. If the method fails, error information can be retrieved using the standard COM IErrorInfo interface.
Remarks
This method returns immediately, and the seek continues in the background. The seek can be canceled by calling any other tuning operation.
Changes the channel to the next higher channel with valid programming, pauses for the specified number of milliseconds, then repeats until canceled.
Syntax
HRESULT ScanUp(
long MillisecondsPause
);
Parameters
- MillisecondsPause
- [in] Variable of type long that specifies the number of milliseconds to pause.
Return Value
Returns S_OK if successful. If the method fails, error information can be retrieved using the standard COM IErrorInfo interface.
Remarks
The call returns immediately, while the scan continues in the background. The scan can be canceled by calling any other tuning operation.
Changes the channel to the next lower channel with valid programming, pauses for the specified number of milliseconds, then repeats until canceled.
Syntax
HRESULT ScanDown(
long MillisecondsPause
);
Parameters
- MillisecondsPause
- [in] Variable of type long that specifies the number of milliseconds to pause.
Return Value
Returns S_OK if successful. If the method fails, error information can be retrieved using the standard COM IErrorInfo interface.
Remarks
The call returns immediately, while the scan continues in the background. The scan can be canceled by calling any other tuning operation.
Scans for all channels with valid programming.
Syntax
HRESULT AutoProgram();
Return Value
Returns S_OK if successful. If the method fails, error information can be retrieved using the standard COM IErrorInfo interface.
Remarks
This method returns immediately, and the scan continues in the background. If the device allows it, the scan can be canceled by calling any other tuning operation. Otherwise, the scan will complete once all channels have been visited once. Internal devices will likely have a software implementation of this feature, and will collect fine-tuning information resulting from the scan. External devices will likely implement this feature, so this is just a means to trigger the process.