MPGAUDIO.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: MpgAudio.h 
* 
* Prototype Mpeg Audio codec 
* 
* 
\**************************************************************************/ 
#ifndef _INC_MPGAUDIO_H 
#define _INC_MPGAUDIO_H 
#include <streams.h> 
#include <windowsx.h> 
#include <mmsystem.h> 
#include <mmreg.h> 
#include <stddef.h> 
#include <string.h> 
 
#include "decoder.h" 
 
 
class CMpegAudioCodec : public CTransformFilter { 
public: 
    // 
    // --- Com stuff --- 
    // 
    static CUnknown * WINAPI CreateInstance(LPUNKNOWN, HRESULT *); 
    STDMETHODIMP NonDelegatingQueryInterface(REFIID riid, void ** ppv); 
    DECLARE_IUNKNOWN; 
 
 
    // 
    // --- CTransform overrides --- 
    // 
    HRESULT Receive(IMediaSample *pSample); 
    HRESULT CheckInputType(const CMediaType* mtIn); 
    HRESULT CheckTransform(const CMediaType* mtIn, const CMediaType* mtOut); 
    HRESULT DecideBufferSize(IMemAllocator * pAllocator, 
                             ALLOCATOR_PROPERTIES * pProperties); 
    HRESULT StartStreaming(); 
    HRESULT StopStreaming(); 
    HRESULT SetMediaType(PIN_DIRECTION direction,const CMediaType *pmt); 
    HRESULT GetMediaType(int iPosition, CMediaType *pMediaType); 
    HRESULT EndOfStream(void); 
    HRESULT EndFlush(void); 
 
    CMpegAudioCodec(TCHAR *pName, LPUNKNOWN pUnk, HRESULT *pHr); 
    ~CMpegAudioCodec(); 
 
private: 
    //  Serialize access to the output pin 
    long            m_FrameSize;        // Frame input size (bytes) 
    long            m_FrameSizeOutput;  // Frame output size (bytes) 
 
    LPBYTE          m_lpStart; 
    LPBYTE          m_lpCurr; 
    LPBYTE          m_lpEnd; 
    BOOL            m_bPayloadOnly; 
 
    enum            {MAX_FRAMES_PER_OUTPUT_SAMPLE = 4}; 
    enum            {AUDIO_BUFF_SIZE = (1024 * 8)}; 
 
    DWORD           m_dwCtrl; 
    AudioCtrl       m_AudioControl; 
    CAudioDecoder   *m_pAudioDecoder; 
 
    CRefTime        m_TimePerFrame; 
    CRefTime        m_TimeAtLastSyncPoint; 
    CRefTime        m_TimeSinceLastSyncPoint; 
 
    int             m_FreqDiv; 
    int             m_PrefChan; 
    int             m_Quality; 
    int             m_QuarterInt; 
    int             m_WordSize; 
 
    BYTE            m_Buffer[AUDIO_BUFF_SIZE]; 
 
    void    ProcessDiscontiuity(IMediaSample *pSample); 
    void    ProcessSyncPoint(IMediaSample *pSample, BYTE *pSrc); 
    HRESULT DeliverSample(IMediaSample *pOutSample, CRefTime &TimeDecoded, 
                          int iSampleSize); 
 
    void    ResetAudioDecoder(); 
    BOOL    LookForSyncWord(); 
    int     Padding(); 
    void    GetNextPacketChunk(LPBYTE &lpPacket, 
                               long &LenLeftInBuffer, long &LenLeftInPacket); 
 
    CRefTime        m_tStop; 
    MPEG1WAVEFORMAT m_Format; 
 
}; 
 
 
// ------------------------------------------------------------------------- 
// Helper functions that can be used by audio and video codecs. 
// ------------------------------------------------------------------------- 
// 
 
/******************************Public*Routine******************************\ 
* ByteSwap 
* 
* Converts dwX from little endian to big endian and vice-versa. 
* 
* 
\**************************************************************************/ 
__inline DWORD 
ByteSwap( 
    DWORD dwX 
    ) 
{ 
#ifdef _X86_ 
    _asm    mov     eax, dwX 
    _asm    bswap   eax 
    _asm    mov     dwX, eax 
 
    return dwX; 
#else 
    return _lrotl(((dwX & 0xFF00FF00) >> 8) | ((dwX & 0x00FF00FF) << 8), 16); 
#endif 
} 
 
LPBYTE SkipToPacketData(LPBYTE pSrc, long &LenLeftInPacket); 
int GetDecoderInteger(const TCHAR *pKey,int iDefault); 
 
#endif