Data Types7

Frame Information Structure

The frame information structure defines a frame for a sequence grabber component and its sequence grabber channel components. The SeqGrabExtendedFrameInfo data type defines the format of a frame information structure. SeqGrabExtendedFrameInfo is an extension of SeqGrabFrameInfo, described in Inside Macintosh: QuickTime Components .



 
struct SeqGrabExtendedFrameInfo {

    wide            frameOffset;

    long            frameTime;

    long            frameSize;

    SGChannel       frameChannel;

    long            frameRefCon;

    SGOutput        frameOutput;

};

typedef struct SeqGrabExtendedFrameInfo SeqGrabExtendedFrameInfo;

typedef SeqGrabExtendedFrameInfo *SeqGrabExtendedFrameInfoPtr;

Field Descriptions

frameOffset: Specifies the offset to the sample. Note that this is a 64-bit value.
frameTime: Specifies the time at which the frame was captured by a sequence grabber channel component. The time value is relative to the data sequence. The channel component must choose a time scale and use it consistently for all sample references.
frameSize: Specifies the number of bytes in the current sample.
frameChannel: Identifies the current connection to the channel component.
frameRefCon: Contains a reference constant for use by the channel component. The channel component uses this constant in any appropriate way--for example, to store a reference to frame differencing information for a time-compressed sequence.
frameOutput: Identifies the sequence grabber output used to store captured data referenced by the current record.

DISCUSSION

SeqGrabExtendedFrameInfo differs from SeqGrabFrameInfo in two respects: frameOffset is a 64-bit value, and frameOutput does not exist in SeqGrabFrameInfo .