xil_cis_seek(3)

NAME

xil_cis_seek − find a particular frame of compressed data in a compressed image sequence

SYNOPSIS

#include <xil/xil.h>

void xil_cis_seek ( XilCis cis,

int framenumber,
int relative_to);

DESCRIPTION

This function sets the read frame of the compressed image sequence (CIS) to a user-specified value.

cis is the input compressed image sequence (CIS) to which the seek applies.

framenumber is the frame offset of the frame, as interpreted by the relative_to argument.

relative_to takes values 0, 1 or 2 depending on whether the offset mentioned above is relative to frame zero of the CIS (0), the current frame (1), or the end of the CIS (2).

Every frame in a CIS has a frame number associated with it; these frame numbers start at zero. Seeking from the beginning of the CIS implies that you are seeking relative to frame number zero and not necessarily the start_frame (the earliest buffered frame that still resides in the CIS). For more information see xil_cis_get_start_frame(3).

If the CIS you are looking in cannot be accessed randomly (see xil_cis_get_random_access(3) ) and you are seeking a frame previous to the current read_frame, an error is generated.

ERRORS

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

EXAMPLES

Go to the 12th frame (from the beginning) of a compressed image sequence:

XilCis cis;
xil_cis_seek( cis, 12, 0 );

NOTES

The framenumber you are seeking must be within the CIS. Use the functions xil_cis_get_start_frame(3) and xil_cis_get_write_frame(3) to determine the legal range of frame numbers.

You cannot use this function to perform random insertions of frames into a CIS. Frames can only be inserted at the end of the CIS, i.e at the write frame.

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