mediaLib Library Functions   mlibVideoIDCT8x8S16S16B12(3MLIB)



NAME
     mlibVideoIDCT8x8S16S16B12,  mlibVideoIDCT8x8S16S16  -
     inverse Discrete Cosine Transform

SYNOPSIS
     cc [ flag... ] file... -lmlib [ library... ]
     #include 

     mlibstatus mlibVideoIDCT8x8S16S16B12(
          mlibs16 block[64], const mlibs16 coeffs[64]);


     mlibstatus mlibVideoIDCT8x8S16S16(
          mlibs16 block[64], const mlibs16 coeffs[64]);


DESCRIPTION
     The mlibVideoIDCT8x8S16S16B12()  function  computes  the
     inverse  DCT (called IDCT) for the output IDCT block of data
     type mlibs16  and  input  DCT  coefficients  of  data  type
     mlibs16.  This  function is not guaranteed to be IE-1180-
     compliant. The output of the IDCT routine should  be  within
     the  range  of  [-2048, 2047] if coeffs is obtained from the
     corresponding         forward          DCT          function
     mlibVideoDCT8x8S16S16B12().


     The source and destination buffer addresses must  be  8-byte
     aligned.


     This function can be used in JPEG with 12-bit precision.


     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.


     Since mediaLib  2.5,  mlibVideoIDCT8x8S16S16()  has  been
     renamed      to     mlibVideoIDCT8x8S16S16B12().     Now
     mlibVideoIDCT8x8S16S16()     is     an      alias      of
     mlibVideoIDCT8x8S16S16B12().

PARAMETERS
     The function takes the following arguments:

     block     Pointer to an 8x8 block in the  current  frame  or
               motion-compensated  reference block. block must be
               8-byte aligned.



SunOS 5.11           Last change: 2 Mar 2007                    1






mediaLib Library Functions   mlibVideoIDCT8x8S16S16B12(3MLIB)



     coeffs    Pointer to the  source  DCT  coefficients.  coeffs
               must be 8-byte aligned.


RETURN VALUES
     The function returns MLIBSUCES if  successful.  Otherwise
     it returns MLIBFAILURE.

ATRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:



     
           ATRIBUTE TYPE               ATRIBUTE VALUE       
    
     Interface Stability          Committed                   
    
     MT-Level                     MT-Safe                     
    


SEE ALSO
     mlibVideoIDCTIES16S16(3MLIB),
     mlibVideoIDCT8x8S16S16B12NA(3MLIB),
     mlibVideoIDCT8x8S16S16DC(3MLIB),
     mlibVideoIDCT8x8S16S16Q1(3MLIB),
     mlibVideoIDCT8x8S16S16Q1Mismatch(3MLIB),
     mlibVideoIDCT8x8U8S16(3MLIB),
     mlibVideoIDCT8x8U8S16DC(3MLIB),
     mlibVideoIDCT8x8U8S16NA(3MLIB),
     mlibVideoIDCT8x8U8S16Q1(3MLIB), attributes(5)






















SunOS 5.11           Last change: 2 Mar 2007                    2