DECODER.H

//==========================================================================; 
// 
//  THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY 
//  KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE 
//  IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR 
//  PURPOSE. 
// 
//  Copyright (c) 1992 - 1997  Microsoft Corporation.  All Rights Reserved. 
// 
//--------------------------------------------------------------------------; 
// 
/******************************Module*Header*******************************\ 
* Module Name: Decoder.h 
* 
* 
* 
* 
\**************************************************************************/ 
 
#ifndef _INC_DECODER_H 
#define _INC_DECODER_H 
 
 
// ------------------------------------------------------------------------- 
// Forward declaration to resolve circular reference. 
// ------------------------------------------------------------------------- 
// 
class CMpegVideoCodec; 
 
enum { 
    SEQUENCE_HEADER_CODE = 0x000001B3, 
    SEQUENCE_END_CODE    = 0x000001B7, 
    GROUP_START_CODE     = 0x000001B8, 
    PICTURE_START_CODE   = 0x00000100 
}; 
 
// ------------------------------------------------------------------------- 
// Video decoder class 
// 
// This class encapsulates a low-level mpeg video decoder. 
// ------------------------------------------------------------------------- 
// 
 
// Decode control option 
enum { 
    DECODE_NULL = 0x0000L,  // Do not Decode any frame. Scan the stream 
    DECODE_I    = 0x0001L,  // I frames only 
    DECODE_IP   = 0x0003L,  // I and P frames 
    DECODE_IPB  = 0x0007L,  // Decode all the frames 
    DECODE_DIS  = 0x0040L   // No Decode, Convert only - force out last frame. 
}; 
 
// Frame Types 
enum { 
    FTYPE_I     = 0x0001L, 
    FTYPE_P     = 0x0002L, 
    FTYPE_B     = 0x0003L 
}; 
 
// Function Return Values 
enum { 
    DECODE_SUCCESS    = 0x0000L, 
    DECODE_ERR_MEMORY = 0x0001L, 
    DECODE_ERR_DATA   = 0x0002L, 
    DECODE_ERR_PARAM  = 0x0004L, 
    DECODE_ERR_QUARTZ = 0x0008L     // error from Quartz callback 
}; 
 
struct VideoCtrl { 
    // 
    // Decoder Output Fields 
    // 
    DWORD   dwGopTimeStamp; // only valid after a GOP, -1 otherwise. 
    DWORD   dwFrameType; 
    LPBYTE  pFrameStartPos; 
    DWORD   dwSkipFlag;     // 1 if the frame was skipped 
    DWORD   dwTemporalReference; 
 
 
    // 
    // Output Frame Buffer 
    // 
    DWORD   dwOutputFormat; 
    DWORD   dwOutputBuffNumber; 
    LPBYTE  pFrameBuff; 
    DWORD   dwOutStride; 
    DWORD   dwOutOffset; 
    DWORD   dwYStride; 
    DWORD   dwYLines; 
 
    // 
    // Frame decoder control 
    // 
    DWORD   dwCtrl; 
 
    // 
    // Input buffer fields 
    // 
    LPBYTE  pCmprRead; 
    LPBYTE  pCmprWrite; 
}; 
 
 
class CVideoDecoder 
    : public CCritSec { 
 
private: 
    // 
    // Back pointer to the object that created us. 
    // 
    CMpegVideoCodec *m_pCodec; 
    VideoCtrl       *m_pCtrl; 
 
    DWORD   NextStartCode(); 
    DWORD   SkipFrame(); 
    void    Discard32Bits(); 
 
public: 
    CVideoDecoder(CMpegVideoCodec *pMpegCodec); 
 
    DWORD   ResetVideo(); 
    DWORD   DecodeFrame(VideoCtrl *pCtrl); 
}; 
#endif