Sensoray 2255 - Manual (Page 15)

channel number (1-4).
pStatus
a pointer to the current video status value. Bit [0]: a value of 1 indicates video signal
present. Bit [8]: 0 for 60Hz signal (usually NTSC,) 1 for 50Hz signal (usually PAL). If Bit [0]
is 0, then the value of bit [8] should be ignored.
Examples:
*pStatus = 0x0100 - no video signal present;
*pStatus = 0x0001 - 60Hz video signal present;
*pStatus = 0x0101 - 50Hz video signal present.
Returns
0 on success.
S2255_QueryBuf(HDEVICE hdev, int channel, int frmnum);
Queries the status of a given buffer.
Parameters
hdev
a handle to the 2255 device.
channel
channel number (1-4).
frmnum
Index of frame in question (starting from 0). Must be smaller than number of registered
buffers.
Returns
Returns 0 if a frame buffer is unused. Returns 1 if a buffer is currently being filled (do not use
buffer). Returns 2 if a buffer is ready (dequeue buffer after use). Returns -1 or negative value
if failure occurs.
S2255_QueryBufExt(HDEVICE hdev, int channel, int frmnum, unsigned int
*ts);
Queries the status of a given buffer and returns timestamp (in milliseconds) of frame.
Parameters
hdev
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