Inside Macintosh: QuickTime Components
Video digitizer components report their current status to your application by means of flags. These flags are formatted as part of the digitizer information structure that you obtain by calling the VDGetDigitizerInfo function (described on VDGetDigitizerInfo ). Alternatively, you can obtain these flags by calling the VDGetCurrentFlags function (described on VDGetCurrentFlags ). There are two sets of flags: one set describes the status of the digitizer with respect to its input signal; the other describes its status with respect to its output.
Video digitizer components report their current status by returning a flags field that contains 1 bit for each of the capability flags (discussed in "Capability Flags," ) plus additional flags as appropriate. The digitizer component sets these flags to reflect its current status. When reporting input status, for example, a video digitizer component sets the digiInDoesGenLock flag to 1 whenever the digitizer component is deriving its time signal from the input video. When reporting its input capabilities, the digitizer component sets this flag to 1 to indicate that it can derive its timing from the input video.
Video digitizer components report their current input status by returning a flags field that contains a bit for each of the input capability flags (discussed in "Capability Flags," ) plus one additional flag.
The additional flag is as follows:
Video digitizer components report their current output status by returning a flags field that contains a bit for each of the output capability flags discussed in "Capability Flags," . The digitizer component sets these flags to reflect its current output status.