swdec_shortvideo.c

freescale i.mx31 BSP CE5.0全部源码

/*------------------------------------------------------------------------------
--                                                                            --
--       This software is confidential and proprietary and may be used        --
--        only as expressly authorized by a licensing agreement from          --
--                                                                            --
--                            Hantro Products Oy.                             --
--                                                                            --
--      In the event of publication, the following notice is applicable:      --
--                                                                            --
--                   (C) COPYRIGHT 2004 HANTRO PRODUCTS OY                    --
--                            ALL RIGHTS RESERVED                             --
--                                                                            --
--         The entire notice above must be reproduced on all copies.          --
--                                                                            --
--------------------------------------------------------------------------------
--
--  Abstract : Short video (h263) decoding functionality 
--
-------------------------------------------------------------------------------*/



/*------------------------------------------------------------------------------

    Table of contents
   
     1. Include headers
     2. External identifiers
     3. Module defines
     4. Module identifiers
     5. Fuctions
        5.1     SwDec_DecodeGobLayer
        5.2     SwDec_DecodeShortVideo
        5.3     SwDec_DecodeShortVideoHeader
        5.4     SwDec_CheckNextGobNumber
        5.5     SwDec_DecodeGobHeader
        5.6     SwDec_InitShortVideo

------------------------------------------------------------------------------*/



/*------------------------------------------------------------------------------
    1. Include headers
------------------------------------------------------------------------------*/

#include "SwDec_ShortVideo.h"
#include "SwDec_Utils.h"
#include "SwDec_MotionTexture.h"

/*------------------------------------------------------------------------------
    2. External identifiers 
------------------------------------------------------------------------------*/


/*------------------------------------------------------------------------------
    3. Module defines 
------------------------------------------------------------------------------*/


/*------------------------------------------------------------------------------
    4. Module indentifiers 
------------------------------------------------------------------------------*/

static const u32 stuffingTable[8] = {0x0,0x1,0x3,0x7,0xF,0x1F,0x3F,0x7F};

STATIC u32 SwDec_DecodeShortVideoHeader(decContainer_t* pDecContainer);
STATIC u32 SwDec_DecodeGobHeader(decContainer_t* pDecContainer);

/*------------------------------------------------------------------------------

   5.1  Function name: SwDec_DecodeGobLayer

        Purpose: decode Group Of Blocks (GOB) layer
                 
        Input: 
            Pointer to decContainer_t structure

        Output:
            HANTRO_OK/HANTRO_NOK/END_OF_STREAM

------------------------------------------------------------------------------*/

u32 SwDec_DecodeGobLayer(decContainer_t *pDecContainer)
{
    u32 tmp;
    u32 mbNumber,mbCounter;
    u32 numMbs;
    u32 stuffingLength;
    u32 status = HANTRO_OK;

    ASSERT(pDecContainer);
#ifndef MP4DEC_H263_ONLY
    ASSERT(pDecContainer->StrmStorage.shortVideo);
#endif
    /* gob header */
    if (pDecContainer->StrmStorage.gobResyncFlag)
    {
        status = SwDec_DecodeGobHeader(pDecContainer);
        if (status != HANTRO_OK) return(status);
        pDecContainer->StrmStorage.vpFirstCodedMb =
            pDecContainer->StrmStorage.vpMbNumber;
    }

    numMbs = pDecContainer->StrmStorage.numMbsInGob;
    mbNumber = pDecContainer->StrmStorage.vpMbNumber;

    mbCounter = 0;

    /*lint --e(716) */
    while(1)
    {
        status = SwDec_DecodeMb(pDecContainer, mbNumber);
        if (status != HANTRO_OK) return(status);
        if (!MB_IS_STUFFING(mbNumber))
        {
            mbNumber++;
            mbCounter++;
            /* read remaining stuffing macro blocks if end of GOB or
             * last MB in vop */
            if ( (mbCounter == numMbs) || 
                    (mbNumber == pDecContainer->VopDesc.totalMbInVop)) 
            {
                /*lint --e(514) */
                tmp = 9 + (pDecContainer->VopDesc.vopCodingType==PVOP);
                while (SwDec_ShowBits(pDecContainer, tmp) == 0x01)
                    (void)SwDec_FlushBits(pDecContainer, tmp); 
                break;
            }
        }
    }

    /* stuffing */
    /* there is stuffing if next byte aligned bits are resync marker or
     * stream ends at next byte aligned position */
    if ( (SwDec_ShowBitsAligned(pDecContainer,17,1) == SC_RESYNC) ||
        ( ((pDecContainer->StrmDesc.strmBuffReadBits>>3) + 1) ==
          pDecContainer->StrmDesc.strmBuffSize ) )
    {
        stuffingLength = 8-pDecContainer->StrmDesc.bitPosInWord;
        tmp = SwDec_ShowBits(pDecContainer, stuffingLength);

        if ( (tmp == 0) || (tmp == stuffingTable[stuffingLength - 1]) )
        {
            SwDec_FlushBits(pDecContainer, stuffingLength);
        }
    }

    /* last gob of vop -> check if short video end code. Read if yes and
    * check that there is stuffing and either end of stream or short video
    * start */
    if (mbNumber == pDecContainer->VopDesc.totalMbInVop)
    {
        tmp = SwDec_ShowBits(pDecContainer,22);
        if (tmp == SC_SV_END)
        {
            (void)SwDec_FlushBits(pDecContainer,22);
        }
        /* read stuffing until stream ends or resync marker or
        * startcode found */
        while( !IS_END_OF_STREAM(pDecContainer) )
        {
            /* check if there is resync marker 
             * or startcode prefix */ 
            tmp = SwDec_ShowBits(pDecContainer, 32);
            if ( (tmp>>15) == 0x1 || 
                 (tmp == SC_VOS_START) || 
                 (tmp == SC_VOS_END))
                break;
            
            stuffingLength = 8-pDecContainer->StrmDesc.bitPosInWord;
            tmp = SwDec_GetBits(pDecContainer, stuffingLength);
            if (tmp == END_OF_STREAM) return (END_OF_STREAM);
            
            if ( (tmp != 0) && (tmp != stuffingTable[stuffingLength - 1]) )
            {
                return(HANTRO_NOK);
            }
        }
#ifndef MP4DEC_H263_ONLY
        /* there might be extra stuffing byte if next start code is video
         * object sequence start or end code. If this is the case the
         * stuffing is normal mpeg4 stuffing. */
        tmp = SwDec_ShowBitsAligned(pDecContainer,32,1);
        if ((tmp == SC_VOS_START) || (tmp == SC_VOS_END))
        {
            tmp = SwDec_GetStuffing(pDecContainer);
            if (tmp != HANTRO_OK) return(tmp);
        }
#endif
        /* check that there is either end of stream or short video start 
         * (only checking that first 17 bits are short video resync marker) or
         * at least 23 zeros in the stream */
        tmp = SwDec_ShowBits(pDecContainer,23);
        if ( !IS_END_OF_STREAM(pDecContainer) &&
             ((tmp>>6) != SC_RESYNC) && tmp )
        {
            return(HANTRO_NOK);
        }
    }

    /* whole video packet decoded and stuffing ok (if stuffed) -> set
     * vpMbNumber in StrmStorage so that this gob layer won't
     * be touched/concealed anymore. Also set VpQP to QP so that concealment
     * will use qp of last decoded macro block. */
    pDecContainer->StrmStorage.vpMbNumber = mbNumber;
    pDecContainer->StrmStorage.vpQP = pDecContainer->StrmStorage.QP;

    pDecContainer->StrmStorage.vpNumMbs = 0;

    return (status);

}
	
/*------------------------------------------------------------------------------

   5.2  Function name: SwDec_DecodeShortVideo

        Purpose: decode VOP with short video header
                 
        Input: 
            Pointer to decContainer_t structure

        Output:
            HANTRO_OK/HANTRO_NOK/END_OF_STREAM

------------------------------------------------------------------------------*/

u32 SwDec_DecodeShortVideo(decContainer_t *pDecContainer)
{
    u32 status = HANTRO_OK;

    ASSERT(pDecContainer);
#ifndef MP4DEC_H263_ONLY
    ASSERT(pDecContainer->StrmStorage.shortVideo);
#endif

    status = SwDec_DecodeShortVideoHeader(pDecContainer);
    if (status != HANTRO_OK) return(status);

    status = SwDec_DecodeGobLayer(pDecContainer);

    return(status);
}
	
/*------------------------------------------------------------------------------

   5.3  Function name: SwDec_DecodeShortVideoHeader

        Purpose: decode short video header
                 
        Input: 
            Pointer to decContainer_t structure

        Output:
            HANTRO_OK/HANTRO_NOK/END_OF_STREAM

------------------------------------------------------------------------------*/

u32 SwDec_DecodeShortVideoHeader(decContainer_t *pDecContainer)
{
    u32 tmp;
    u32 ufep = 0;

    /* check that previous vop was finished, if it wasnt't return start code
     * into the stream and get away */
    if (pDecContainer->StrmStorage.vpMbNumber)
    {
        (void)SwDec_UnFlushBits(pDecContainer,22);
        pDecContainer->StrmStorage.pLastSync =
            pDecContainer->StrmDesc.pStrmCurrPos;
        return(HANTRO_NOK);
    }
    
    pDecContainer->StrmStorage.validVopHeader = 0;
    
    /* temporal reference. Note that arithmetics are performed only with