Current File : //usr/man/man3mlib/mlib_VideoIDCT8x8_S16_S16_B12.3mlib

'\" te
.\" Copyright (c) 2007, Sun Microsystems, Inc.  All Rights Reserved 
.TH mlib_VideoIDCT8x8_S16_S16_B12 3MLIB "2 Mar 2007" "SunOS 5.11" "mediaLib Library Functions"
.SH NAME
mlib_VideoIDCT8x8_S16_S16_B12, mlib_VideoIDCT8x8_S16_S16 \- inverse Discrete Cosine Transform
.SH SYNOPSIS
.LP
.nf
cc [ \fIflag\fR... ] \fIfile\fR... \fB-lmlib\fR [ \fIlibrary\fR... ]
#include <mlib.h>

\fBmlib_status\fR \fBmlib_VideoIDCT8x8_S16_S16_B12\fR(
     \fBmlib_s16\fR \fIblock[64]\fR, \fBconst mlib_s16\fR \fIcoeffs[64]\fR);
.fi

.LP
.nf
\fBmlib_status\fR \fBmlib_VideoIDCT8x8_S16_S16\fR(
     \fBmlib_s16\fR \fIblock[64]\fR, \fBconst mlib_s16\fR \fIcoeffs[64]\fR);
.fi

.SH DESCRIPTION
.sp
.LP
The \fBmlib_VideoIDCT8x8_S16_S16_B12()\fR function computes the inverse DCT (called IDCT) for the output IDCT block of data type mlib_s16 and input DCT coefficients of data type mlib_s16. This function is not guaranteed to be IEEE-1180-compliant. The output of the IDCT routine should be within the range of [-2048, 2047] if \fBcoeffs\fR is obtained from the corresponding forward DCT function \fBmlib_VideoDCT8x8_S16_S16_B12()\fR.
.sp
.LP
The source and destination buffer addresses must be 8-byte aligned.
.sp
.LP
This function can be used in JPEG with 12-bit precision.
.sp
.LP
For MPEG, the output, which is really the difference between the current block and the reference block, can occupy nine bits and is represented as a 16-bit datum. The output must be added to the motion-compensated reference block in order to reconstruct the current block.
.sp
.LP
Since mediaLib 2.5, \fBmlib_VideoIDCT8x8_S16_S16()\fR has been renamed to \fBmlib_VideoIDCT8x8_S16_S16_B12()\fR. Now \fBmlib_VideoIDCT8x8_S16_S16()\fR is an alias of \fBmlib_VideoIDCT8x8_S16_S16_B12()\fR.
.SH PARAMETERS
.sp
.LP
The function takes the following arguments:
.sp
.ne 2
.mk
.na
\fB\fIblock\fR\fR
.ad
.RS 10n
.rt  
Pointer to an 8x8 block in the current frame or motion-compensated reference block. \fBblock\fR must be 8-byte aligned.
.RE

.sp
.ne 2
.mk
.na
\fB\fIcoeffs\fR\fR
.ad
.RS 10n
.rt  
Pointer to the source DCT coefficients. \fBcoeffs\fR must be 8-byte aligned.
.RE

.SH RETURN VALUES
.sp
.LP
The function returns \fBMLIB_SUCCESS\fR if successful. Otherwise it returns \fBMLIB_FAILURE\fR.
.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(5) for descriptions of the following attributes:
.sp

.sp
.TS
tab() box;
cw(2.75i) |cw(2.75i) 
lw(2.75i) |lw(2.75i) 
.
ATTRIBUTE TYPEATTRIBUTE VALUE
_
Interface StabilityCommitted
_
MT-LevelMT-Safe
.TE

.SH SEE ALSO
.sp
.LP
\fBmlib_VideoIDCT_IEEE_S16_S16\fR(3MLIB), \fBmlib_VideoIDCT8x8_S16_S16_B12_NA\fR(3MLIB), \fBmlib_VideoIDCT8x8_S16_S16_DC\fR(3MLIB), \fBmlib_VideoIDCT8x8_S16_S16_Q1\fR(3MLIB), \fBmlib_VideoIDCT8x8_S16_S16_Q1_Mismatch\fR(3MLIB), \fBmlib_VideoIDCT8x8_U8_S16\fR(3MLIB), \fBmlib_VideoIDCT8x8_U8_S16_DC\fR(3MLIB), \fBmlib_VideoIDCT8x8_U8_S16_NA\fR(3MLIB), \fBmlib_VideoIDCT8x8_U8_S16_Q1\fR(3MLIB), \fBattributes\fR(5)