IAMTimecodeReader::GetTimecode
| Microsoft DirectShow 9.0 |
IAMTimecodeReader::GetTimecode
The GetTimecode method retrieves the most recent timecode, userbit, and flag values available in the stream.
Syntax
HRESULT GetTimecode( TIMECODE_SAMPLE *pTimecodeSample );
Parameters
pTimecodeSample
[out] Pointer to a TIMECODE_SAMPLE structure.
Return Values
Returns an HRESULT value that depends on the implementation of the interface.
Remarks
Use this method to monitor the timecode and to parse duplicates and discontinuities.
The timecode contains undefined bits, called userbits. Applications can use these bits to store synchronization information or other custom information.
DV and MPEG Camcorder Implementation
The MSDV driver supports reading SMPTE timecode or absolute track numbers (ATN). The MSTape driver supports reading the relative time counter (RTC). To read time information on these devices, do the following:
Set the dwFlags member of the TIMECODE_SAMPLE structure to one of the following values.
| Constant | Description |
| ED_DEVCAP_TIMECODE_READ | Timecode (DV) |
| ED_DEVCAP_ATN_READ | Absolute track number (DV) |
| ED_DEVCAP_RTC_READ | Relative time counter (MPEG tape) |
The timecode member of the TIMECODE_SAMPLE structure is a TIMECODE structure. Initialize that structure's dwFrames member to zero.
All other structure members are ignored.
When the method returns, the dwFrames member contains the time information, in the following format.
| Time Information | Format |
| Timecode | Hours, minutes, seconds, and frames, as a binary coded decimal (BCD) value: 0xhhmmssff. |
| ATN | Track number. |
| RTC | Hours, minutes, seconds, and frames, as a BCD value: 0xhhmmssff. The most significant bit of the frames byte is a sign bit. If the frame count is not available, the remaining frame bits are set to 0x7F. |
Also, the dwUser member receives the blank flag bit from the device, which has one of the following values.
| Value | Description |
| 0x00 | Not a discontinuity. |
| 0x01 | Discontinuity. |
Requirements
Header: Declared in Strmif.h; include Dshow.h.
Library: Use Strmiids.lib.
See Also