Application-Defined Functions(IM: QC)

Inside Macintosh: QuickTime Components /: Chapter 5 - Sequence Grabber Components / Sequence Grabber Components Reference

Application-Defined Functions
This section describes the functions that your application may supply to sequence grabber components.
Your grab function is used by the sequence grabber component to begin the capture of a frame of video data. Your grab-complete function allows the sequence grabber component to determine whether the current frame-capture operation is complete.
Your display function enables the sequence grabber component to move a captured video image in an offscreen buffer into the destination buffer for the video channel.
The sequence grabber component uses your compress function to commence the compression of a captured video image. Your compress-complete function helps the sequence grabber component to find out if the current frame-compression operation is finished.
Your add-frame function lets the sequence grabber component add a frame to a movie.
The sequence grabber component uses your transfer-frame function to move a video frame from the capture buffer into the channel's filter buffer.
You may provide two functions for use with compressed-source devices. Your grab-compress-complete function determines when the current capture and compress operation is complete. Your display-compress function decompresses and displays a frame.
The sequence grabber calls your data function whenever any of the grabber's channels write data to the movie file.
If you call the SGSettingsDialog function, described on page 5-45, you must supply a modal-dialog filter function. The interface that your function must provide is discussed on page 5-117.