VDGetMaxAuxBuffer(IM: QC)

Inside Macintosh: QuickTime Components /

Chapter 8 - Video Digitizer Components / Video Digitizer Components Reference

Video Digitizer Component Functions / Setting Video Destinations

VDGetMaxAuxBuffer
The VDGetMaxAuxBuffer function allows applications to obtain access to buffers that are located on special hardware. Digitizer components that are constrained to a single output device can provide an auxiliary buffer to support multiple buffering.
pascal VideoDigitizerError VDGetMaxAuxBuffer
                               (VideoDigitizerComponent ci,
                                  PixMapHandle *pm, Rect *r);
ci
Specifies the video digitizer component for the request. Applications obtain this reference from the Component Manager's OpenComponent function.
pm
Contains a pointer to a pixel map handle. The video digitizer component returns a handle to the destination pixel map in the field referred to by this parameter. Do not dispose of this pixel map. If the digitizer component cannot allocate a buffer, this handle is set to nil.
r
Contains a pointer to a rectangle structure. The video digitizer component places the coordinates of the largest output rectangle it can support into the structure referred to by this parameter.

DESCRIPTION
You can use the VDGetMaxAuxBuffer function in your application to determine whether a video digitizer component supports an auxiliary buffer. If the digitizer component provides an auxiliary buffer, it is to your advantage to use it. By using the buffer, you may achieve better performance under some circumstances, such as when the digitizer component does not support DMA.

RESULT CODES