xil_cis_get_start_frame(3)

NAME

xil_cis_get_start_frame, xil_cis_get_read_frame, xil_cis_get_write_frame − obtain frame status attributes.

SYNOPSIS

#include <xil/xil.h>

int xil_cis_get_start_frame (XilCis cis);

int xil_cis_get_read_frame (XilCis cis);

int xil_cis_get_write_frame (XilCis cis);

DESCRIPTION

In each of these routines, cis is the input compressed image sequence (CIS). Every frame in a CIS has a frame number associated with it. The beginning of the CIS is frame number zero. A CIS may have one or more frames buffered in memory. The start_frame is the index of the earliest buffered frame that still resides in the CIS. The read_frame is the index of the next frame that will be read by routines such as xil_cis_get_bits_ptr(3) or xil_decompress(3). The write_frame is the next frame that will be written. Routines such as xil_cis_put_bits_ptr(3) or xil_compress(3) add new frames immediately at this frame and increment the write_frame index each time they write a frame.

xil_cis_get_start_frame() returns the index, relative to the beginning of the CIS, of the first compressed image still buffered in the CIS.

xil_cis_get_read_frame() returns the index of the current read frame, i.e. the one that will be decompressed next.

xil_cis_get_write_frame() returns the index of the next frame to be written. Thus, write_frame - 1 is the last complete frame in the CIS. If a partial or an unknown number of frames exist in the CIS because calls to xil_cis_put_bits()
or xil_cis_put_bits_ptr() have not yet been resolved, then the decompressor must parse the data to determine how many frames are in the CIS. This can make xil_cis_get_write_frame() potentially expensive.

ERRORS

For a complete list of XIL error messages by number, consult Appendix B of the XIL Programmer’s Guide.

EXAMPLES

XilCis cis;
printf("Current Read Frame is %d\n",
xil_cis_get_read_frame(cis));

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