NVIDIA Corporation
Quadro FX 4500/5500 SDI User’s Guide – Version 2.0 67
CHAPTER 5
API Control
•If, rather than using the GLX_NV_video_out extension to display GLX pbuffers on
the GVO output, you wish display the X screen on the GVO output, set
NV_CTRL_GVO_DISPLAY_X_SCREEN to
NV_CTRL_GVO_DISPLAY_X_SCREEN_ENABLE.
• Setting most GVO attributes only causes the value to be cached in the X server.
The values will be flushed to the hardware either when
NV_CTRL_GVO_DISPLAY_X_SCREEN is enabl ed, or w hen a GLX pbuffe r is bou nd to
the GVO output (with glXBindVideoImageNV()).
• GLX_NV_video_out and NV_CTRL_GVO_DISPLAY_X_SCREEN are mutually
exclusive.
If NV_CTRL_GVO_DISPLAY_X_SCREEN is enabled, then glXGetVideoDeviceNV will
fail. Similarly, if a GLX client has locked the GVO output (via glXGetVideoDeviceNV),
then NV_CTRL_GVO_DISPLAY_X_SCREEN will fail. The NV_CTRL_GVO_LOCKED
event will be sent when a GLX client locks the GVO output.
NV_CTRL_GVO Attributes

NV_CTRL_GVO_SUPPORTED

/*
* NV_CTRL_GVO_SUPPORTED - returns whether this X screen supports GVO;
* if this screen does not support GVO output, then all other GVO
* attributes are unavailable.
*/
#define NV_CTRL_GVO_SUPPORTED 67 /* R-- */
#define NV_CTRL_GVO_SUPPORTED_FALSE 0
#define NV_CTRL_GVO_SUPPORTED_TRUE 1

NV_CTRL_GVO_SYNC_MODE

/*
* NV_CTRL_GVO_SYNC_MODE - selects the GVO sync mode; possible values
* are:
*
* FREE_RUNNING - GVO does not sync to any external signal
*
* GENLOCK - the GVO output is genlocked to an incoming sync signal;
* genlocking locks at hsync. This requires that the output video