TUNER_ANALOG_CAPS_S structure (ksmedia.h)
The TUNER_ANALOG_CAPS_S structure describes the hardware scanning capabilities of a tuning device that supports an analog broadcast network.
Syntax
typedef struct {
ULONG Mode;
ULONG StandardsSupported;
ULONG MinFrequency;
ULONG MaxFrequency;
ULONG TuningGranularity;
ULONG SettlingTime;
ULONG ScanSensingRange;
ULONG FineTuneSensingRange;
} TUNER_ANALOG_CAPS_S, *PTUNER_ANALOG_CAPS_S;
Members
Mode
The current tuner mode, which can be represented by one of the following tuner mode flags from the KSPROPERTY_TUNER_MODES enumeration that is defined in Ksmedia.h.
| Flag | Meaning |
|---|---|
| KSPROPERTY_TUNER_MODE_TV | The tuner is currently tuning broadcast or cable television channels. |
| KSPROPERTY_TUNER_MODE_FM_RADIO | The tuner is currently tuning FM radio channels. |
| KSPROPERTY_TUNER_MODE_AM_RADIO | The tuner is currently tuning AM radio channels. |
| KSPROPERTY_TUNER_MODE_DSS | The tuner is currently tuning DSS channels. |
| KSPROPERTY_TUNER_MODE_ATSC | The tuner is capable of tuning Advanced Television Systems Committee broadcasts (Digital TV for the United States). This setting can also be used by DVB-T and DVB-C systems. |
StandardsSupported
If the Mode member is set to KSPROPERTY_TUNER_MODE_TV or KSPROPERTY_TUNER_MODE_DSS, a bitwise OR of values from the KS_AnalogVideoStandard enumeration that indicates the analog video standards that the tuner supports. Otherwise, this member is ignored.
MinFrequency
The lowest frequency, in Hz, that the tuner supports.
MaxFrequency
The highest frequency, in Hz, that the tuner supports.
TuningGranularity
The smallest possible step size, in Hz, between two settings of the tuning frequency.
SettlingTime
The time, in milliseconds, for a new frequency setting to become stable.
KsTvTune.ax uses the value in SettlingTime to evaluate the total time its scanning algorithm might take so that it can determine wait time. The value in SettlingTime along with the number of stepping increments in the entire frequency range that is based on the sensing range should provide an estimate of the total time that is required for the scanning algorithm.
ScanSensingRange
The range that the tuning device provides and that the tuner filter uses to determine the presence of a signal. This range represents the larger step sizes that a signal search algorithm can use to advance through the range of frequencies to search. The driver can report the actual lock frequency of a signal and the lock status on the signal through a call to the driver's KSPROPERTY_TUNER_SCAN_STATUS property. If the driver reports the lock status as Tuner_LockType_Within_Scan_Sensing_Range in the LockStatus member of the KSPROPERTY_TUNER_SCAN_STATUS_S structure, the increment step size changes to the smaller value in FineTuneSensingRange until the actual lock frequency is determined.
FineTuneSensingRange
The range that the tuning device provides and that the tuner filter uses to determine the actual frequency of a signal. The tuner filter uses this fine-tune-sensing range only when the underlying tuner hardware cannot support hardware-assisted scanning. The driver indicates such support by setting the fSupportsHardwareAssistedScanning member of the KSPROPERTY_TUNER_SCAN_CAPS_S structure to TRUE in a call to its KSPROPERTY_TUNER_SCAN_CAPS property. When the tuner filter starts a scan, it initially probes the driver in increments within the range that the ScanSensingRange member specifies until the driver returns Tuner_LockType_Within_Scan_Sensing_Range. The tuner filter then switches into steps of FineTuneSensingRange until the driver reports a complete lock.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Available in Windows Vista and later versions of the operating system. |
| Header | ksmedia.h (include Ksmedia.h) |