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
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frameOffset
-
Specifies the offset to the sample. Note that this is a 64-bit value.
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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.
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frameChannel
-
Identifies the current connection to the channel component.
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frameRefCon
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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.
