img_mpeg2_vld_inter.h

TMS320C64x Image／Video Processing Library (V1.04)

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/*  TEXAS INSTRUMENTS, INC.                                                 */
/*                                                                          */
/*  IMGLIB  DSP Image/Video Processing Library                              */
/*                                                                          */
/*      Release:        Revision 1.04b                                      */
/*      CVS Revision:   1.11    Sun Sep 29 03:32:26 2002 (UTC)              */
/*      Snapshot date:  23-Oct-2003                                         */
/*                                                                          */
/*  This library contains proprietary intellectual property of Texas        */
/*  Instruments, Inc.  The library and its source code are protected by     */
/*  various copyrights, and portions may also be protected by patents or    */
/*  other legal protections.                                                */
/*                                                                          */
/*  This software is licensed for use with Texas Instruments TMS320         */
/*  family DSPs.  This license was provided to you prior to installing      */
/*  the software.  You may review this license by consulting the file       */
/*  TI_license.PDF which accompanies the files in this library.             */
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/*          Copyright (C) 2003 Texas Instruments, Incorporated.             */
/*                          All Rights Reserved.                            */
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/*  Assembler compatibility shim for assembling 4.30 and later code on      */
/*  tools prior to 4.30.                                                    */
/* ======================================================================== */
/* ======================================================================== */
/*  End of assembler compatibility shim.                                    */
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/*  TEXAS INSTRUMENTS, INC.                                                 */
/*                                                                          */
/*  NAME                                                                    */
/*      IMG_mpeg2_vld_inter                                                 */
/*                                                                          */
/*  PLATFORM                                                                */
/*      C6400                                                               */
/*                                                                          */
/*  REVISION DATE                                                           */
/*      23-May-2002                                                         */
/*                                                                          */
/*  DESCRIPTION                                                             */
/*      This routine takes a bitstream of an MPEG-2 non-intra coded         */
/*      macroblock and returns the decoded IDCT coefficients. The routine   */
/*      is implemented as specified in the MPEG-2 standard text (ISO/IEC    */
/*      13818-2). The routine checks the coded block pattern (cbp),         */
/*      performs coefficient decoding inlcuding, variable length decode,    */
/*      run-length expansion, inverse zigzag, dequantization, saturation    */
/*      and mismatch control.                                               */
/*                                                                          */
/*  USAGE                                                                   */
/*      This routine is C callable, and has the following C prototype:      */
/*                                                                          */
/*      void IMG_mpeg2_vld_inter                                            */
/*      (                                                                   */
/*          const short    *restrict Wptr,                                  */
/*          short          *restrict outi,                                  */
/*          IMG_mpeg2_vld  *restrict Mpeg2v,                                */
/*          int            mode_12Q4,                                       */
/*          int            num_blocks,                                      */
/*          int            bsbuf_words                                      */
/*      );                                                                  */
/*                                                                          */
/*        Wptr:   Pointer to array that contains quantization matrix. The   */
/*                elements of the quantization matrix in *Wptr must be      */
/*                ordered according to the scan pattern used (zigzag or     */
/*                alternate scan). Video format 4:2:0 requires one          */
/*                quantization matrix (64 array elements).  For formats     */
/*                4:2:2 and 4:4:4 two quantization matrices (one for luma   */
/*                and one for chroma) must specified in the array (128      */
/*                array elements).                                          */
/*                                                                          */
/*        outi:   Pointer to the IDCT coefficients output array             */
/*                (6*64 elements), elements must be set to zero prior to    */
/*                function call.                                            */
/*                                                                          */
/*        Mpeg2v: Pointer to the context object containing the coding       */
/*                parameters of the MB to be decoded and the current state  */
/*                of the bitstream buffer. The structure is described       */
/*                below.                                                    */
/*                                                                          */
/*     mode_12Q4: 0: Coefficients are returned in normal 16-bit integer     */
/*                format.                                                   */
/*                Otherwise: Coefficients are returned in 12Q4 format       */
/*                (normal 16-bit integer format left shifted by 4). This    */
/*                mode is useful for directly passing the coefficients      */
/*                into the IMG_idct_8x8 routine.                            */
/*                                                                          */
/*    num_blocks: Number of blocks that the MB contains. Valid values are   */
/*                6 for 4:2:0, 8 for 4:2:2 and 12 for 4:4:4 format.         */
/*                                                                          */
/*   bsbuf_words: Size of bitstream buffer in words. Must be a power of 2.  */
/*                Bitstream buffer must be aligned at an address boundary   */
/*                equal to its size in bytes (bitstream buffer is           */
/*                addressed circularly by this routine.)                    */
/*                                                                          */
/*      The structure Mpeg2v is defined as follows:                         */
/*                                                                          */
/*          #ifndef IMG_MPEG2_VLD_STRUCT_                                   */
/*          #define IMG_MPEG2_VLD_STRUCT_ 1                                 */
/*                                                                          */
/*          typedef struct {                                                */
/*            unsigned int  *bsbuf;      // pointer to bitstream buffer     */
/*            unsigned int  next_wptr;   // next word to read from buffer   */
/*            unsigned int  bptr;        // bit position within word        */
/*            unsigned int  word1;       // word aligned buffer             */
/*            unsigned int  word2;       // word aligned buffer             */
/*            unsigned int  top0;        // top 32 bits of bitstream        */
/*            unsigned int  top1;        // next 32 bits of bitstream       */
/*            const unsigned char *scan; // inverse zigzag scan matrix      */
/*            unsigned int  intravlc;    // intra_vlc_format                */
/*            unsigned int  quant_scale; // quant_scale                     */
/*            unsigned int  dc_prec;     // intra_dc_precision              */
/*            unsigned int  cbp;         // coded_block_pattern             */
/*            unsigned int  fault;       // fault condition (returned)      */
/*            unsigned int  reserved;    // reserved                        */
/*          } IMG_mpeg2_vld;                                                */
/*                                                                          */
/*          #endif                                                          */
/*                                                                          */
/*      The Mpeg2v variables should  have a fixed layout since they are     */
/*      accessed by this routine. If the layout is changed, the             */
/*      corresponding changes have to be made in the assembly code too.     */
/*                                                                          */
/*      The routine sets the fault flag Mpeg2v.fault to 1 if an invalid     */
/*      VLC code was encountered or the total run went beyond 63. In        */
/*      theses cases the decoder has to resynchronize.                      */
/*                                                                          */
/*      The required lookup tables for this routine are provided in         */
/*      IMGLIB and are linked in automatically when linking against         */
/*      IMGLIB.                                                             */
/*                                                                          */
/*      Before calling the routine the bitstream varaibles in Mpeg2v        */
/*      have to be initialized. If bsbuf is a circular buffer and bsptr     */
/*      contains the number of bits in the buffer that already have         */
/*      been consumed, then next_wptr, bptr, word1, word2, top0 and         */
/*      top1 are initialized as follows:                                    */