Windows Media Audio compressor

//
//  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. IT CAN BE DISTRIBUTED FREE OF CHARGE AS LONG AS THIS HEADER 
//  REMAINS UNCHANGED.
//
//  Email:  yetiicb@hotmail.com
//
//  Copyright (C) 2002-2004 Idael Cardoso. 
//
#include "StdAfx.h"
#include ".\wmawriter.h"
#include <wmsdk.h>

#using <mscorlib.dll>

CWmaWriter::CWmaWriter(WAVEFORMATEX __nogc* pInFormat, IWMProfile __nogc* pProfile, IWMWriterSink __nogc* pSink)
{
  if ( (pInFormat ==NULL) || (pProfile == NULL) || (pSink ==NULL) )
  {
    AtlThrow(E_INVALIDARG);
  }
  m_MsAudioTime = 0;
  m_cAudioBytes = 0;
  m_AvgBytesPerSec = pInFormat->nAvgBytesPerSec;
  ATLTHROW_IF_FAILED(WMCreateWriter(NULL, &m_Writer))
  CComPtr<IWMWriterAdvanced> pWriterAdvanced;
  ATLTHROW_IF_FAILED(m_Writer.QueryInterface(&pWriterAdvanced));
  ATLTHROW_IF_FAILED(pWriterAdvanced->AddSink(pSink));
  m_Sink = pSink;
  ATLTHROW_IF_FAILED(m_Writer->SetProfile(pProfile))
  
  DWORD   cInputs = 0;
  ATLTHROW_IF_FAILED(m_Writer->GetInputCount(&cInputs));
  
  CComPtr<IWMInputMediaProps>  pProps;
  GUID InputType;
  WM_MEDIA_TYPE   mt;
  
  mt.majortype			= WMMEDIATYPE_Audio;
  mt.subtype				= WMMEDIASUBTYPE_PCM;
  mt.bFixedSizeSamples	= TRUE;
  mt.bTemporalCompression = FALSE;
  mt.lSampleSize			= pInFormat->nBlockAlign;
  mt.formattype			= WMFORMAT_WaveFormatEx;
  mt.pUnk					= NULL;
  mt.cbFormat				= sizeof( WAVEFORMATEX ) + pInFormat->cbSize;
  mt.pbFormat				= (BYTE*)pInFormat;
  for(DWORD input = 0; input < cInputs; input++)
  {
    pProps = NULL;
    m_AudioInput = input;
    ATLTHROW_IF_FAILED(m_Writer->GetInputProps(input, &pProps));
    ATLTHROW_IF_FAILED(pProps->GetType(&InputType));
    if (InputType != WMMEDIATYPE_Audio)
    {
      AtlThrow(E_INVALIDARG); //Only Audio profile 
    }
    ATLTHROW_IF_FAILED(pProps->SetMediaType(&mt));
    ATLTHROW_IF_FAILED(m_Writer->SetInputProps(input, pProps));
  }
  ATLTHROW_IF_FAILED(m_Writer->BeginWriting());
}

CWmaWriter::~CWmaWriter(void)
{
  if (m_Writer.p != NULL)
  {
    CComPtr<IWMWriterAdvanced> pWriterAdvanced;
    m_Writer->EndWriting();
    if( SUCCEEDED(m_Writer.QueryInterface(&pWriterAdvanced)) )
    {
      pWriterAdvanced->RemoveSink(m_Sink);
    }
  }
}

void CWmaWriter::Write(INSSBuffer* pSample)
{
  DWORD Length;
  pSample->GetLength(&Length);
  ATLTHROW_IF_FAILED(m_Writer->WriteSample(m_AudioInput, m_MsAudioTime * 10000, 0, pSample));
  m_cAudioBytes += Length;
  m_MsAudioTime += MulDiv(Length, 1000, m_AvgBytesPerSec);
}

void CWmaWriter::Write(BYTE* pBuffer, DWORD Length)
{
  if (m_Writer.p != NULL)
  {
    CComPtr<INSSBuffer> pSample;
    BYTE* pSampleBuff;
    ATLTHROW_IF_FAILED(m_Writer->AllocateSample(Length, &pSample));
    ATLTHROW_IF_FAILED(pSample->GetBuffer(&pSampleBuff));
    memcpy(pSampleBuff, pBuffer, Length);
    ATLTHROW_IF_FAILED(pSample->SetLength(Length));
    Write(pSample);
  }
  else
  {
    AtlThrow(E_POINTER);
  }
}


INSSBuffer* CWmaWriter::AllocateSample(DWORD Length)
{
  if (m_Writer.p != NULL)
  {
    INSSBuffer* pSample = NULL;
    m_Writer->AllocateSample(Length, &pSample);
    return pSample;
  }
  else
  {
    return NULL;
  }
}