AVC_VCR_CMD_RELATIVE_TIME_COUNTER (Windows CE 5.0)
This command permits the caller to either query or set the VCR subunits internal relative time counter. The relative time counter is a time counter of the current position on the inserted media to an arbitrary position on the tape, such as where the tape was wound at the point it was inserted.
Parameters
- Command
This must be set to AVC_VCR_CMD_RELATIVE_TIME_COUNTER. - CommandType
If the caller wants to query the current setting, this field must be set to AVC_VCR_CommandType_Status. If the caller wants to set the VCR subunit to a specific date, this field must be set to AVC_VCR_CommandType_Control. - u.RelativeTimeCounter.Negative
If the caller is attempting to query the current relative time-counter setting, this field need not be initialized. If the caller is attempting to set the current value, this field should be set to the frame number in the relative time-counter value that the caller wants to set or RELATIVE_TIME_COUNTER_Frame_Unused in the event that the frame value is unknown or unused. - u.RelativeTimeCounter.Frame
If querying the current relative time-counter setting, this does not need to be initialized. If setting the current value, this should be set to the frame number in the relative time-counter value that you want to set, or RELATIVE_TIME_COUNTER_Frame_Unused if the frame value is unknown or unused. - u.RelativeTimeCounter.Second
If the caller is attempting to query the current relative time-counter setting, this field need not be initialized. If the caller is attempting to set the current value, this field should be set to the seconds value in the relative time-counter value that the caller wants to set. This field has a range from 0 to 59. - u.RelativeTimeCounter.Minute
If the caller is attempting to query the current relative time-counter setting, this field need not be initialized. If the caller is attempting to set the current value, this field should be set to the minutes value in the relative time-counter value that the caller wants to set. This field has a range from 0 to 59. - u.RelativeTimeCounter.Hour
If the caller is attempting to query the current relative time-counter setting, this field need not be initialized. If the caller is attempting to set the current value, this field should be set to the hours value in the relative time-counter value that the caller wants to set. This field has a range of 0 to 99. Although some VCR types may limit it further.
Return Values
- ResponseCode
The VCR subunit will return a specific value in this field, depending on the requested action and the capabilities of the subunits. A successful query may result in a value of AVC_RESPONSE_STABLE, while a successful control attempt will result in a value of AVC_RESPONSE_ACCEPTED. Other values are possible and are discussed in the description of IOCTL_VCR_AVCCMD. - u.RelativeTimeCounter.Negative
If the caller was attempting to set the current relative time-counter value, this field is indeterminate. If the caller was attempting to query the current relative time-counter setting, this field should contain a Boolean value that indicates whether the relative time-counter code returned was negative or positive. If negative, a TRUE should be returned. If positive, a FALSE should be returned. - u.RelativeTimeCounter.Frame
If the caller was attempting to set the current relative time-counter value, this field is indeterminate. If the caller was attempting to query the current relative time-counter setting, this field should contain the frame number in the current relative time-counter setting, or the value of RELATIVE_TIME_COUNTER_Frame_Unused if the frame value is either unavailable or unused. - u.RelativeTimeCounter.Second
If the caller was attempting to set the current relative time-counter value, this field is indeterminate. If the caller was attempting to query the current relative time-counter setting, this field should contain the second's value in the current relative time-counter setting. - u.RelativeTimeCounter.Minute
If the caller was attempting to set the current relative time-counter value, this field is indeterminate. If the caller was attempting to query the current relative time-counter setting, this field should contain the minute's value in the current relative time-counter setting. - u.RelativeTimeCounter.Hour
If the caller was attempting to set the current relative time-counter value, this field is indeterminate. If the caller was attempting to query the current relative time-counter setting, this field should contain the hour's value in the current relative time-counter setting.
Remarks
Although reviewing the AV/C VCR Subunit Specification is an excellent resource for interpreting some of the finer details of these commands, it is not a conclusive guide. For example, all BCD values in the protocol are automatically translated for the caller by the TVPAK VCR subunit driver, and the caller should never expect nor provide a BCD value for a field.
Requirements
OS Versions: Windows CE .NET 4.0 and later.
Header: Avc_vcr.h.
See Also
Send Feedback on this topic to the authors