Inside Macintosh: QuickTime Components /

Chapter 6 - Sequence Grabber Channel Components / Sequence Grabber Channel Components Reference

Functions / Controlling Sequence Grabber Channel Components

SGPrepare

The SGPrepare function instructs your component to get ready to begin a preview or record operation (or both)--the sequence grabber component specifies the operations.

pascal ComponentResult SGPrepare (SeqGrabComponent s, 
                                  Boolean prepareForPreview,
                                  Boolean prepareForRecord);

s

Identifies the sequence grabber component that has connected to your channel component.

prepareForPreview

Instructs your component to prepare for a preview operation. The sequence grabber component sets this parameter to true to prepare for a preview operation. The sequence grabber component may set both the prepareForPreview and prepareForRecord parameters to true.

prepareForRecord

Instructs your component to prepare for a record operation. The sequence grabber component sets this parameter to true to prepare for a record operation. The sequence grabber component may set both the prepareForPreview and prepareForRecord parameters to true.

DESCRIPTION

Your component should do whatever is necessary to get ready to start the operation. The goal is to reduce the delay between the time when the sequence grabber calls your SGStartPreview function (described on page 6-38) or SGStartRecord function (described on page 6-39) and the time when the operation actually begins. This may involve allocating memory or readying special hardware.

SPECIAL CONSIDERATIONS

If the sequence grabber calls SGPrepare without subsequently starting a record or preview operation, it calls the SGRelease function (described in the next section) later. This allows your component to release any system resources it allocated during the SGPrepare function.

RESULT CODES

paramErr	-50	Invalid parameter specified
notEnoughDiskSpaceToGrab	-9404	Insufficient disk space for record operation
deviceCantMeetRequest	-9408	Device cannot support grabber

File Manager errors
Memory Manager errors

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