Source code of Windows XP (NT5)
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//
// syslink.cpp
//
/*
Copyright (c) 1998-2000 Microsoft Corporation. All Rights Reserved.
*/
#include "common.h"
#include "private.h"
#define STR_MODULENAME "DDKSynth.sys:SysLink: "
/*****************************************************************************
*****************************************************************************
* CDmSynthStream-- ISynthSinkDMus implementation
*****************************************************************************
****************************************************************************/
#pragma code_seg()
/*****************************************************************************
* CDmSynthStream::Render()
*****************************************************************************
* Render is called from the port driver, to fill the given buffer. This is
* in turn forwarded to the synth (which -- roughly -- goes to the different
* voices, which goes to the DigitalAudios, which goes to the mix functions).
*
* Typically, a synthesizer manages converting messages into
* rendered wave data in two processes. First, it time stamps the MIDI
* messages it receives from the application via calls to
* PlayBuffer and places them in its own internal queue.
*
* Then, in response to Render, it generates audio by pulling MIDI
* messages from the queue and synthesizing the appropriate tones within
* the time span of the requested render buffer.
*
* As the synthesizer renders the MIDI messages into the buffer, it
* calls RefTimeToSample to translate the MIDI time stamps into sample
* positions. This guarantees extremely accurate timing.
*/
void CDmSynthStream::Render(
IN PBYTE pBuffer,
IN DWORD dwLength,
IN LONGLONG llPosition)
{
PAGED_CODE();
_DbgPrintF(DEBUGLVL_BLAB, ("CDmSynthStream::Render"));
ASSERT(pBuffer);
m_pSynth->Mix((short*)pBuffer, dwLength, llPosition);
m_llLastPosition = llPosition + dwLength;
}
/*****************************************************************************
* CDmSynthStream::SyncToMaster()
*****************************************************************************
* Sync this stream to the master clock, using the given slave time, and
* whether we are starting now.
*/
STDMETHODIMP
CDmSynthStream::SyncToMaster(IN REFERENCE_TIME rtSlaveTime,
IN BOOL fStart)
{
PAGED_CODE();
_DbgPrintF(DEBUGLVL_BLAB, ("CDmSynthStream::SyncToMaster"));
REFERENCE_TIME rtMasterTime;
m_pMasterClock->GetTime(&rtMasterTime);
if (!fStart)
{
m_SampleClock.SyncToMaster(rtSlaveTime, rtMasterTime);
}
else
{
m_llStartPosition = ((rtSlaveTime / 1000) * m_PortParams.SampleRate) / 10000;
m_SampleClock.Start(m_pMasterClock, m_PortParams.SampleRate, m_llStartPosition);
}
return S_OK;
}
/*****************************************************************************
* CDmSynthStream::SampleToRefTime()
*****************************************************************************
* Translate between sample time and reference clock time.
*/
STDMETHODIMP
CDmSynthStream::SampleToRefTime(IN LONGLONG llSampleTime,
OUT REFERENCE_TIME * prtTime)
{
_DbgPrintF(DEBUGLVL_BLAB, ("CDmSynthStream::SampleToRefTime"));
ASSERT(prtTime);
m_SampleClock.SampleToRefTime(llSampleTime + m_llStartPosition, prtTime);
return S_OK;
}
/*****************************************************************************
* CDmSynthStream::RefTimeToSample()
*****************************************************************************
* Translate between sample time and reference clock time.
*/
STDMETHODIMP
CDmSynthStream::RefTimeToSample(IN REFERENCE_TIME rtTime,
OUT LONGLONG * pllSampleTime)
{
_DbgPrintF(DEBUGLVL_BLAB, ("CDmSynthStream::RefTimeToSample"));
ASSERT(pllSampleTime);
*pllSampleTime = m_SampleClock.RefTimeToSample(rtTime) - m_llStartPosition;
return S_OK;
}