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      1 /**
      2  *
      3  * File Name:  omxVCM4P2_EncodeVLCZigzag_Inter.c
      4  * OpenMAX DL: v1.0.2
      5  * Revision:   9641
      6  * Date:       Thursday, February 7, 2008
      7  *
      8  * (c) Copyright 2007-2008 ARM Limited. All Rights Reserved.
      9  *
     10  *
     11  *
     12  * Description:
     13  * Contains modules for zigzag scanning and VLC encoding
     14  * for inter block.
     15  *
     16  */
     17 
     18 #include "omxtypes.h"
     19 #include "armOMX.h"
     20 #include "omxVC.h"
     21 
     22 #include "armVC.h"
     23 #include "armCOMM_Bitstream.h"
     24 #include "armCOMM.h"
     25 #include "armVCM4P2_Huff_Tables_VLC.h"
     26 #include "armVCM4P2_ZigZag_Tables.h"
     27 
     28 
     29 
     30 /**
     31  * Function:  omxVCM4P2_EncodeVLCZigzag_Inter   (6.2.4.5.3)
     32  *
     33  * Description:
     34  * Performs classical zigzag scanning and VLC encoding for one inter block.
     35  *
     36  * Input Arguments:
     37  *
     38  *   ppBitStream - pointer to the pointer to the current byte in the bit
     39  *            stream
     40  *   pBitOffset - pointer to the bit position in the byte pointed by
     41  *            *ppBitStream. Valid within 0 to 7
     42  *   pQDctBlkCoef - pointer to the quantized DCT coefficient
     43  *   pattern - block pattern which is used to decide whether this block is
     44  *            encoded
     45  *   shortVideoHeader - binary flag indicating presence of
     46  *            short_video_header; escape modes 0-3 are used if
     47  *            shortVideoHeader==0, and escape mode 4 is used when
     48  *            shortVideoHeader==1.
     49  *
     50  * Output Arguments:
     51  *
     52  *   ppBitStream - *ppBitStream is updated after the block is encoded so that
     53  *            it points to the current byte in the bit stream buffer.
     54  *   pBitOffset - *pBitOffset is updated so that it points to the current bit
     55  *            position in the byte pointed by *ppBitStream.
     56  *
     57  * Return Value:
     58  *
     59  *    OMX_Sts_NoErr - no error
     60  *    OMX_Sts_BadArgErr - Bad arguments
     61  *    -    At least one of the pointers: is NULL: ppBitStream, *ppBitStream,
     62  *              pBitOffset, pQDctBlkCoef
     63  *    -   *pBitOffset < 0, or *pBitOffset >7.
     64  *
     65  */
     66 OMXResult omxVCM4P2_EncodeVLCZigzag_Inter(
     67      OMX_U8 **ppBitStream,
     68      OMX_INT * pBitOffset,
     69      const OMX_S16 *pQDctBlkCoef,
     70      OMX_U8 pattern,
     71 	 OMX_INT shortVideoHeader
     72 )
     73 {
     74     OMX_U8 start = 0;
     75     const OMX_U8  *pZigzagTable = armVCM4P2_aClassicalZigzagScan;
     76 
     77     /* Argument error checks */
     78     armRetArgErrIf(ppBitStream == NULL, OMX_Sts_BadArgErr);
     79     armRetArgErrIf(*ppBitStream == NULL, OMX_Sts_BadArgErr);
     80     armRetArgErrIf(pBitOffset == NULL, OMX_Sts_BadArgErr);
     81     armRetArgErrIf(pQDctBlkCoef == NULL, OMX_Sts_BadArgErr);
     82     armRetArgErrIf((*pBitOffset < 0) || (*pBitOffset >7), OMX_Sts_BadArgErr);
     83 
     84     if (pattern)
     85     {
     86         armVCM4P2_PutVLCBits (
     87               ppBitStream,
     88               pBitOffset,
     89               pQDctBlkCoef,
     90               shortVideoHeader,
     91               start,
     92               26,
     93               40,
     94               10,
     95               1,
     96               armVCM4P2_InterL0RunIdx,
     97               armVCM4P2_InterVlcL0,
     98 			  armVCM4P2_InterL1RunIdx,
     99               armVCM4P2_InterVlcL1,
    100               armVCM4P2_InterL0LMAX,
    101               armVCM4P2_InterL1LMAX,
    102               armVCM4P2_InterL0RMAX,
    103               armVCM4P2_InterL1RMAX,
    104               pZigzagTable
    105         );
    106     } /* Pattern check ends*/
    107 
    108     return OMX_Sts_NoErr;
    109 
    110 }
    111 
    112 /* End of file */
    113