omxacaac_decodedatstrelt.c

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

/**
 * 
 * File Name:  omxACAAC_DecodeDatStrElt.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 DSE information from AAC bitstream
 *
 */

#include "omxtypes.h" 
#include "armOMX.h"
#include "omxAC.h"

#include "armCOMM.h"
#include "armCOMM_Bitstream.h"
 
/**
 * Function:  omxACAAC_DecodeDatStrElt   (3.2.3.1.5)
 *
 * Description:
 * Gets data_stream_element from the input bit stream. 
 *
 * Reference: [ISO14496-3], Table 4.10 
 *
 * Input Arguments:
 *   
 *   ppBitStream - double 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 - double pointer to the current byte after the decode data 
 *            stream 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. 
 *   pDataTag - pointer to element_instance_tag. 
 *   pDataCnt - pointer to the value of length of total data in bytes 
 *   pDstDataElt - pointer to the data stream buffer that contains the data 
 *            stream extracted from the input bit stream.  There are 512 
 *            elements in the buffer pointed by pDstDataElt. 
 *
 * Return Value:
 *    
 *    OMX_Sts_NoErr - no error 
 *    OMX_Sts_BadArgErr - bad arguments 
 *    -    At least one of the following pointers is NULL: 
 *           - ppBitStream,
 *           - pOffset, 
 *           - *ppBitStream, 
 *           - pDataTag, 
 *           - pDataCntor 
 *           - pDstDataElt. 
 *    -  *pOffset exceeds [0, 7] 
 *
 */
  
OMXResult omxACAAC_DecodeDatStrElt(
     const OMX_U8 **ppBitStream,
     OMX_INT *pOffset,
     OMX_INT *pDataTag,
     OMX_INT *pDataCnt,
     OMX_U8 *pDstDataElt
 )
{
    OMX_INT  nextData,count;
    OMX_INT  i;
    
    /* Argument Check */        
    armRetArgErrIf( ppBitStream  == NULL , OMX_Sts_BadArgErr);
    armRetArgErrIf(*ppBitStream  == NULL , OMX_Sts_BadArgErr);
    armRetArgErrIf( pOffset      == NULL , OMX_Sts_BadArgErr);
    armRetArgErrIf( pDataTag     == NULL , OMX_Sts_BadArgErr);
    armRetArgErrIf( pDataCnt     == NULL , OMX_Sts_BadArgErr);
    armRetArgErrIf( pDstDataElt  == NULL , OMX_Sts_BadArgErr);

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

    /* Processing */
    *pDataTag   = (OMX_INT)armGetBits(ppBitStream,pOffset,4);/*element_instance_tag*/
    nextData    = (OMX_INT)armGetBits(ppBitStream,pOffset,1);/*data_byte_align_flag*/
    count       = (OMX_INT)armGetBits(ppBitStream,pOffset,8);/*cnt*/
    
    if(count == 255)
    {
        count  += (OMX_INT)armGetBits(ppBitStream,pOffset,8);/*esc_count*/
    }
    *pDataCnt = count;
    
    if(nextData == 1)
    {
        /*data_byte_align_flag*/
        armByteAlign(ppBitStream,pOffset);
    }
    
    for(i = 0; i < count ; i++)
    {
        pDstDataElt[i]   = (OMX_INT)armGetBits(ppBitStream,pOffset,8);/*data_stream_byte*/
    }
    
    return OMX_Sts_NoErr;
}

 /* End of File */