avsdeclib.cpp

AVS是中国自己推出的视频图像音频编解码标准。包中是AVS 源代码

/*************************************************************************
 AVS1-P2视频解码器源码
 版权所有：联合信源数字音视频技术（北京）有限公司, (c) 2005-2006 

 AVS1-P2 Video Decoder Source Code
 (c) Copyright, NSCC All Rights Reserved, 2005-2006
 *************************************************************************
 Distributed under the terms of the GNU General Public License as
 published by the Free Software Foundation; either version 2 of the
 License, or (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software
 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*************************************************************************/

/*************************************************************************
  本代码为AVS1-P2标准视频解码器的源代码，实现了AVS1-P2标准文本中所规定的
  绝大部分功能，但不包括：
  1) 场编码(field coding)
  2) 多Slice结构
  3) 加权预测
  4) 去伪起始码
 *************************************************************************/
/*************************************************************************
  Revision History
  data          Modification                                    Author
  2006-3-12     Created                                          jthou
 *************************************************************************/
#include "define.h"
#include "avsdeclib.h"
#include "global.h"
#include "decode.h"
#include "stream.h"

//////////////////////////////////////////////////////////////////////////
// global variables

  STREAMINFO strmInfo;
  AVS_BYTE* pbBuf = (AVS_BYTE*)calloc(INBUFLEN*2, sizeof(AVS_BYTE));

  VIDEODATA* videoBuf[3];
  VIDEODATA* pRefFrame[2];
  VIDEODATA* pCurrFrame;
  VIDEODATA* videoFieldBuf[5];
  VIDEODATA* pRefField[4];
  MBINFO* pMbInfo;
  BWREFINFO* pBwRefInfo;
  bool firstFrame;

int OpenAVSDec(BYTE* pbData, int len, SEQ_INFO* pInfo)
{
  if(DWORD_SWAP(*(AVS_DWORD*)pbData)!= SEQENCE_START_CODE)
    return AVS_FALSE;
  if(len < 20)
    return AVS_NOT_ENOUGH_DATA;

  pBwRefInfo =  new BWREFINFO[MAX_MB_NUM];
  pMbInfo = new MBINFO[MAX_MB_NUM];
  firstFrame = 1;

  GetMem(videoBuf, 3);
  GetMem(videoFieldBuf, 5);

  // Init reference frame buffer
  pRefFrame[0] = videoBuf[0];
  pRefFrame[1] = videoBuf[1];
  pCurrFrame = videoBuf[2];

  InitDecode(pbData, len, &strmInfo);

  pInfo->image_width = strmInfo.SeqInfo.dwWidth;
  pInfo->image_height = strmInfo.SeqInfo.dwHeight;
  pInfo->frame_rate = strmInfo.SeqInfo.fFrameRate;
}

int GetOneFrameBitsFromBuffer(unsigned char *pFrameBuf, int iBufLen, int *pFrameLen, int* pNoUseDataLen)
{
  AVS_BYTE* pbData = pFrameBuf;
  AVS_INT iLeft = iBufLen;
  AVS_INT iNoUseDatalen = 0;
  
  *pFrameLen = 0;
  *pNoUseDataLen = 0;
  
  while (pbData[0] != 0x00 ||
    pbData[1] != 0x00 ||
    pbData[2] != 0x01)
  {
    pbData ++;
    iLeft --;
    (*pNoUseDataLen) ++;
    if(iLeft < 4)
      return 0;
  }

  while(1)
  {
    switch(pbData[(*pNoUseDataLen)+3])
    {
    case 0xB0:    // Sequence Header 
     if(!FindNextPicOrEndStartCode(pbData, iBufLen, (AVS_DWORD*)&iLeft))
       return AVS_NOT_ENOUGH_DATA;
      SeqenceHeader(pbData, iBufLen, &(strmInfo.SeqInfo));
      
      *pNoUseDataLen += iBufLen-iLeft;
      break;
    case 0xB5:    // Extension 
     if(!FindNextPicOrEndStartCode(pbData+*pNoUseDataLen, iBufLen, (AVS_DWORD*)&iLeft))
       return AVS_NOT_ENOUGH_DATA;
      *pNoUseDataLen += iBufLen-iLeft;
      break;
    case 0xB2:    // User Data
     if(!FindNextPicOrEndStartCode(pbData+*pNoUseDataLen, iBufLen, (AVS_DWORD*)&iLeft))
       return AVS_NOT_ENOUGH_DATA;
      *pNoUseDataLen = iBufLen-iLeft;
      break;
    case 0xB3:    // I frame
     if(!FindNextPicOrEndStartCode(pbData+*pNoUseDataLen, iBufLen, (AVS_DWORD*)&iLeft))
       return AVS_NOT_ENOUGH_DATA;
      *pFrameLen = iBufLen-iLeft+*pNoUseDataLen;
      return 1;
    case 0xB6:    // PB frame
     if(!FindNextPicOrEndStartCode(pbData+*pNoUseDataLen, iBufLen, (AVS_DWORD*)&iLeft))
       return AVS_NOT_ENOUGH_DATA;
      *pFrameLen = iBufLen-iLeft+*pNoUseDataLen;
      return 1;
    case 0xB1:    // Sequence End
      return 0;
    }
  }
}

int DecOneFrameFromBuffer(unsigned char *pbData, int iFrameLen, BYTE** ppOutY, BYTE** ppOutU, BYTE** ppOutV)
{
  if(DWORD_SWAP(*(AVS_DWORD*)pbData)==I_FRAME_START_CODE || DWORD_SWAP(*(AVS_DWORD*)pbData) == PB_FRAME_START_CODE)
  {
    DecodeOneFrame(pbData, iFrameLen, &strmInfo, pRefFrame, &pCurrFrame, pMbInfo, pBwRefInfo);
  }
  if(firstFrame)
  {
    *ppOutY = pRefFrame[0]->y;
    *ppOutU = pRefFrame[0]->u;
    *ppOutV = pRefFrame[0]->v; 
    firstFrame = FALSE;
  }
  else if((strmInfo.ImgInfo.dwImageType != B_IMG ))
  {
    *ppOutY = pRefFrame[1]->y;
    *ppOutU = pRefFrame[1]->u;
    *ppOutV = pRefFrame[1]->v; 
  }
  else
  {
    *ppOutY = pCurrFrame->y;
    *ppOutU = pCurrFrame->u;
    *ppOutV = pCurrFrame->v; 
  }

  return AVS_NOERROR;
}

void CloseAVSDec()
{
  delete []pBwRefInfo;
  delete []pMbInfo;
  ReleaseMem(videoBuf, 3);
  ReleaseMem(videoFieldBuf, 5);
}