omxacaac_decodefillelt.c

The OpenMAX DL (Development Layer) APIs contain a comprehensive set of audio, video, signal processi

/**
 * 
 * File Name:  omxACAAC_DecodeFillElt.c
 * OpenMAX DL: v1.0.2
 * Revision:   10586
 * Date:       Wednesday, March 5, 2008
 * 
 * (c) Copyright 2007-2008 ARM Limited. All Rights Reserved.
 * 
 * 
 *
 * Description:
 * This file contains module for parsing FILL Element information from AAC bitstream
 *
 */
 
#include "omxtypes.h"
#include "omxAC.h"
#include "armOMX.h"

#include "armCOMM.h"
#include "armCOMM_Bitstream.h"

/**
 * Function:  omxACAAC_DecodeFillElt   (3.2.3.1.6)
 *
 * Description:
 * Gets the fill element from the input bit stream. 
 *
 * Reference: [ISO14496-3], Table 4.11 
 *
 * Input Arguments:
 *   
 *   ppBitStream - pointer to the pointer to the current byte 
 *   pOffset - pointer to the bit position in the byte pointed by 
 *            *ppBitStream. Valid within 0 to 7. 0: MSB of the byte, 7: LSB of 
 *            the byte 
 *
 * Output Arguments:
 *   
 *   ppBitStream - pointer to the pointer to the current byte after the 
 *            decode fill element 
 *   pOffset - pointer to the bit position in the byte pointed by 
 *            *ppBitStream. Valid within 0 to 7. 0: MSB of the byte, 7: LSB of 
 *            the byte. 
 *   pFillCnt - pointer to the value of the length of total fill data in 
 *            bytes 
 *   pDstFillElt- pointer to the fill data buffer of length 270 
 *
 * Return Value:
 *    
 *    OMX_Sts_NoErr - no error 
 *    OMX_Sts_BadArgErr - bad arguments 
 *    -    At least one of the following pointers is NULL:  
 *           - ppBitStream, 
 *           - pOffset, 
 *           - *ppBitStream, 
 *           - pFillCnt,
 *           - pDstFillElt.
 *    -   *pOffset exceeds [0, 7] 
 *
 */

OMXResult omxACAAC_DecodeFillElt(
     const OMX_U8 **ppBitStream,
     OMX_INT *pOffset,
     OMX_INT *pFillCnt,
     OMX_U8 *pDstFillElt
 )
{
    OMX_INT FillCnt,extType;
    OMX_INT nDyn,nExc,drcNumBands;
    OMX_INT TempVar,i;
    
    /* Argument Check */        
    armRetArgErrIf( ppBitStream  == NULL , OMX_Sts_BadArgErr);
    armRetArgErrIf(*ppBitStream  == NULL , OMX_Sts_BadArgErr);
    armRetArgErrIf( pOffset      == NULL , OMX_Sts_BadArgErr);
    armRetArgErrIf( pFillCnt     == NULL , OMX_Sts_BadArgErr);
    armRetArgErrIf( pDstFillElt  == NULL , OMX_Sts_BadArgErr);

    armRetArgErrIf( (*pOffset > 7) || (*pOffset < 0) , OMX_Sts_BadArgErr);

    FillCnt = (OMX_INT)armGetBits(ppBitStream,pOffset,4);
    
    if(FillCnt == 15)
    {
        FillCnt += ( (OMX_INT)armGetBits(ppBitStream,pOffset,8) - 1 );
    }
    
    *pFillCnt = FillCnt;
    
    while(FillCnt > 0)
    {
        /*Extension Payload */
         extType = (OMX_INT)armGetBits(ppBitStream,pOffset,4);
         
         switch(extType)
         {
            
            case 11: /* 0b1011 */
                /* EXT_DYNAMIC_RANGE */
            
                /* Dynamic Range info */
                nDyn = 1;
                drcNumBands = 1;
                
                TempVar = (OMX_INT)armGetBits(ppBitStream,pOffset,1);/*pce_tag_present*/
                
                if(TempVar == 1)
                {
                    armSkipBits(ppBitStream,pOffset,8);
                    nDyn++;
                }
                
                TempVar = (OMX_INT)armGetBits(ppBitStream,pOffset,1);/*excluded_chns_present*/
                
                if (TempVar == 1)
                {
                    
                    /* Excluded_channels */
                    
                    nExc = 1;
                    armSkipBits(ppBitStream,pOffset,7);/*exclude_mask*/
                    
                    TempVar = (OMX_INT)armGetBits(ppBitStream,pOffset,1);/* additional_excluded_chns */
                    
                    while(TempVar == 1)
                    {
                        armSkipBits(ppBitStream,pOffset,7);/*exclude_mask*/
                        
                        nExc++;
                        
                        TempVar = (OMX_INT)armGetBits(ppBitStream,pOffset,1);/* additional_excluded_chns */
                    }
                    
                    nDyn = nDyn + nExc;
                }
                
                TempVar = (OMX_INT)armGetBits(ppBitStream,pOffset,1);/* drc_bands_present */
                
                if(TempVar == 1)
                {
                    TempVar = (OMX_INT)armGetBits(ppBitStream,pOffset,4);/* drc_band_incr */                

                    armSkipBits(ppBitStream,pOffset,4);/*drc_bands_reserved_bits*/

                    drcNumBands += TempVar;
                    nDyn        += drcNumBands + 1;

                    TempVar = ( drcNumBands << 3);
                    armSkipBits(ppBitStream,pOffset,TempVar);
                    
                }
                
                TempVar = (OMX_INT)armGetBits(ppBitStream,pOffset,1);/* prog_ref_level_present */
                
                if(TempVar == 1)
                {
                    armSkipBits(ppBitStream,pOffset,8);
                    nDyn++;
                }
                
                TempVar = (drcNumBands << 3);
                armSkipBits(ppBitStream,pOffset,TempVar);
                
                nDyn += drcNumBands;
                
                FillCnt -= nDyn;
                break;

            case 1: /* 0b0001: */
                /* EXT_FILL_DATA */
                
                TempVar = (OMX_INT)armGetBits(ppBitStream,pOffset,4);/*fill_nibble*/
                
                TempVar = ( (extType << 4) | TempVar );
                pDstFillElt[0] = TempVar ;
                
                for (i = 0 ; i < (FillCnt - 1) ; i++)
                {
                    pDstFillElt[i+1] = (OMX_U8)armGetBits(ppBitStream,pOffset,8);
                }
                
                FillCnt -= FillCnt;
                break;
                
            default:
                
                TempVar = (OMX_INT)armGetBits(ppBitStream,pOffset,4);
                
                TempVar = (extType << 4) | TempVar;
                pDstFillElt[0] = TempVar ;
                
                for (i = 0 ; i < (FillCnt - 1) ; i++)
                {
                    pDstFillElt[i+1] = (OMX_U8)armGetBits(ppBitStream,pOffset,8);
                }
                
                FillCnt -= FillCnt;
                
                break;

         } /*End switch - case*/
    
    }/*End while()*/
    
    return OMX_Sts_NoErr;
}
/* End of File */