examples/Multimedia/MmfExFormatPlugin/mmfrawformat.cpp

/*
Copyright (c) 2002-2010 Nokia Corporation and/or its subsidiary(-ies). All rights reserved.

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modification, are permitted provided that the following conditions are met:

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  list of conditions and the following disclaimer.
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  this list of conditions and the following disclaimer in the documentation
  and/or other materials provided with the distribution.
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  may be used to endorse or promote products derived from this software
  without specific prior written permission.

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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Description:  
*/


// MMF framework headers
#include <mmffile.h>
#include <ecom.h>
#include <mmfformatimplementationuids.hrh>
#include <mmffourcc.h>

#include "mmfrawformat.h"
#include "UIDs.hrh"

const TUint KFormatDefaultFrameSize(0x1000); //Set default frame size to 4 K
const TUint KDefineIOBufferSize(0x0200); //easy to read clip buffer size
const TUint KOneSecondInMicroSeconds(1000000); //1 Second
const TUint KMono(1);
const TUint KStereo(2);
//this defines the valid sample rates for RAW
const TUint KRawSampleRates[] = { 8000, 11025, 22050, 44100 };


//
// CMMFRawFormatRead
//

// Factory function
CMMFFormatDecode* CMMFRawFormatRead::NewL(MDataSource* aSource)
        {
        if ((aSource->DataSourceType()==KUidMmfDescriptorSource)||
                        (aSource->DataSourceType()==KUidMmfFileSource))
                {//currently only files and descriptor MDataSources are supported
                CMMFRawFormatRead* self = new(ELeave)CMMFRawFormatRead;
                CleanupStack::PushL(self);
                self->ConstructL(aSource);
                CleanupStack::Pop();
                return self;
                }
        else return NULL;
        }

// Destructor
CMMFRawFormatRead::~CMMFRawFormatRead()
        {
        delete iBuffer;
        }
        
// Second-phase constructor
void CMMFRawFormatRead::ConstructL(MDataSource* aSource)
        {
        // tell clip we're using it
        iClip = aSource;
        User::LeaveIfError(iClip->SourceThreadLogon(*this));
        iClip->SourcePrimeL();
        iFrameSize = KFormatDefaultFrameSize;
        iClipLength = (static_cast<CMMFClip*>(iClip))->Size();
        }

// Implementing MDataSource

// Handle request to fill buffer with data from clip
void CMMFRawFormatRead::FillBufferL(CMMFBuffer* aBuffer, MDataSink* aConsumer, TMediaId aMediaId )
        {       
        // check media id & pass onto the clip
        if (aMediaId.iMediaType != KUidMediaTypeAudio) User::Leave(KErrNotSupported); 
        iDataPath = aConsumer;
        //assumes first frame is frame 1
        TUint position = ((aBuffer->FrameNumber()-1)*iFrameSize)+iStartPosition;
        (static_cast<CMMFClip*>(iClip))->ReadBufferL(aBuffer, position, this);
        // notified of when buffer is full by BufferFilledL
        }

// creates the buffer for the source
// This overload supplies the sink buffer, as optimal source buffer size creation may depend on this
CMMFBuffer* CMMFRawFormatRead::CreateSourceBufferL(TMediaId aMediaId, CMMFBuffer& aSinkBuffer, TBool &aReference)
        {
        if (aMediaId.iMediaType == KUidMediaTypeAudio) 
                {
                NegotiateSourceBufferL(aSinkBuffer); //sets frame size to match sink buffer
                return CreateSourceBufferL(aMediaId, aReference);
                }
        else User::Leave(KErrNotSupported);
        return NULL;
        }

// creates the buffer for the source
CMMFBuffer* CMMFRawFormatRead::CreateSourceBufferL(TMediaId aMediaId, TBool &aReference)
        {
        if (aMediaId.iMediaType == KUidMediaTypeAudio) 
                {
                // assume default frame size if haven't determined a better one
                if (!iFrameSize) iFrameSize = KFormatDefaultFrameSize;
                // sets aReference to false if a new CMMFBuffer is returned
                aReference = EFalse;
                return CreateSourceBufferOfSizeL(iFrameSize);
                }
        else User::Leave(KErrNotSupported);
        return NULL;
        }

// Helper function to create and zero fill a buffer of specified size
CMMFDataBuffer* CMMFRawFormatRead::CreateSourceBufferOfSizeL(TUint aSize)
        {
        //needs to create source buffer
        CMMFDataBuffer* buffer = CMMFDataBuffer::NewL(aSize);
        buffer->Data().FillZ(aSize);
        return buffer;
        }

// Helper function to determine best source buffer size
void CMMFRawFormatRead::NegotiateSourceBufferL(CMMFBuffer& aSinkBuffer)
        {
        // if sink buffer has a fixed size use this to determine source buffer size
        if (aSinkBuffer.Type() == KUidMmfDataBuffer)
                {
                // RAW is linear data, so can set target buffer to sink buffer size
                TUint sinkBufferLength = (static_cast<CMMFDataBuffer&>(aSinkBuffer)).Data().MaxLength();
                if (sinkBufferLength == 0) sinkBufferLength = KFormatDefaultFrameSize;
                iFrameSize = sinkBufferLength; 
                CalculateFrameTimeInterval();
                }
        else 
                User::Leave(KErrNotSupported);
        }

// returns the codec FourCC code for the mediaId
TFourCC CMMFRawFormatRead::SourceDataTypeCode(TMediaId aMediaId)
        {
        if (aMediaId.iMediaType == KUidMediaTypeAudio) return iFourCC;
        else return TFourCC(); //defaults to 'NULL' fourCC
        }

// sets the codec FourCC code for the mediaId
TInt CMMFRawFormatRead::SetSourceDataTypeCode(TFourCC aSinkFourCC, TMediaId aMediaId)
        {
        if (aMediaId.iMediaType != KUidMediaTypeAudio) return KErrNotSupported;
        else iFourCC = aSinkFourCC;
        
        if ((iFourCC == KMMFFourCCCodePCM16) || 
                (iFourCC == KMMFFourCCCodePCM16B) || 
                (iFourCC == KMMFFourCCCodePCMU16)) 
                        iBitsPerSample = 16;
        else if ((iFourCC == KMMFFourCCCodeIMAD) || 
                (iFourCC == KMMFFourCCCodeIMAS)) 
                        iBitsPerSample = 4;
        else 
                        iBitsPerSample = 8; //default to 8
        return KErrNone;
        }

// Initiate use of the interface 
TInt CMMFRawFormatRead::SourceThreadLogon(MAsyncEventHandler& aEventHandler)
        {//pass through to source clip
        return(iClip->SourceThreadLogon(aEventHandler));
        }

// Prepare clip
void CMMFRawFormatRead::SourcePrimeL()
        {
        iClip->SourcePrimeL();
        CalculateFrameTimeInterval();
        }

// Play clip
void CMMFRawFormatRead::SourcePlayL()
        {
        iClip->SourcePlayL();
        }

// Pause clip
void CMMFRawFormatRead::SourcePauseL()
        {
        iClip->SourcePauseL(); //propagate state change down to clip
        }

// Stop clip
void CMMFRawFormatRead::SourceStopL()
        {
        iClip->SourceStopL();
        }

// End use of the interface
void CMMFRawFormatRead::SourceThreadLogoff()
        {
        iClip->SourceThreadLogoff();
        }

// from MDataSink

// called by MDataSource to pass back full buffer to the sink
void CMMFRawFormatRead::BufferFilledL(CMMFBuffer* aBuffer)
        {
        //set position
        TTimeIntervalMicroSeconds position = //assumes frame numbers begin at frame 1
                TTimeIntervalMicroSeconds(TInt64(aBuffer->FrameNumber()-1)*iFrameTimeInterval.Int64());
        aBuffer->SetTimeToPlay(position);
        iDataPath->BufferFilledL(aBuffer);      
        }


// from CMMFFormatDecode

// returns number of streams
TUint CMMFRawFormatRead::Streams(TUid aMediaType) const
        {
        //need to check aMediaType for audio
        if (aMediaType == KUidMediaTypeAudio) return 1; //raw files can only have 1 audio stream
        else return 0;
        }

// returns the time interval for one frame
TTimeIntervalMicroSeconds CMMFRawFormatRead::FrameTimeInterval(TMediaId aMediaId) const
        {
        if (aMediaId.iMediaType == KUidMediaTypeAudio) return iFrameTimeInterval;
        else return TTimeIntervalMicroSeconds(0);
        }

// returns the duration of the source clip
TTimeIntervalMicroSeconds CMMFRawFormatRead::Duration(TMediaId aMediaId) const
        {
        if ((aMediaId.iMediaType == KUidMediaTypeAudio) && 
                (iClipLength) && (iSampleRate) && (iBitsPerSample) && (iChannels))
                {//we have enough values to calculate the duration
                TInt64 clipLength(iClipLength);
                clipLength*=KOneSecondInMicroSeconds;
                TTimeIntervalMicroSeconds duration = TTimeIntervalMicroSeconds(clipLength/iSampleRate);
                duration = TTimeIntervalMicroSeconds(duration.Int64()/(iBitsPerSample*iChannels));
                duration = TTimeIntervalMicroSeconds(duration.Int64()*8);
                return duration;
                }
        else return TTimeIntervalMicroSeconds(0);
        }

// helper function: calculates time between frames
void CMMFRawFormatRead::CalculateFrameTimeInterval()
        {
        if ((iFrameSize) && (iSampleRate) && (iBitsPerSample) && (iChannels))
                {
                iFrameTimeInterval = TTimeIntervalMicroSeconds((iFrameSize*KOneSecondInMicroSeconds)/iSampleRate);
                iFrameTimeInterval = 
                        TTimeIntervalMicroSeconds(iFrameTimeInterval.Int64()/(iBitsPerSample*iChannels));
                iFrameTimeInterval = TTimeIntervalMicroSeconds(iFrameTimeInterval.Int64()*8);
                }
        }

// called by sink to suggest a source buffer size
void CMMFRawFormatRead::SuggestSourceBufferSize(TUint aSuggestedBufferSize)
        {
        iFrameSize = aSuggestedBufferSize; //set source format frame size to buffer size suggested by sink
        CalculateFrameTimeInterval();
        }

// set the number of channels
TInt CMMFRawFormatRead::SetNumChannels(TUint aChannels)
        {
        TInt error = KErrNone;
        if ((aChannels ==  KMono)||(aChannels == KStereo)) iChannels = aChannels;
        else error = KErrNotSupported; //only alow one or two channels
        return error;
        }

// set the sample rate
TInt CMMFRawFormatRead::SetSampleRate(TUint aSampleRate)
        {
        TInt status = KErrNotSupported;
        //we'll iterate through the valid sample table
        TInt i = sizeof(KRawSampleRates) / sizeof(TUint);
                
        while ((i--) && (status != KErrNone))
                {
                if (aSampleRate == KRawSampleRates[i])
                        {
                        iSampleRate = aSampleRate;
                        status = KErrNone;
                        }
                }
        return status;
        }

// helper function to read from clip
void CMMFRawFormatRead::DoReadL(TInt aReadPosition)
        {
        STATIC_CAST(CMMFClip*,iClip)->ReadBufferL(iBuffer,aReadPosition);
        }

// get the supported sample rates
void CMMFRawFormatRead::GetSupportedSampleRatesL(RArray<TUint>& aSampleRates)
        {
        aSampleRates.Reset();

        // Iterate through the valid sample table and append each value to aSampleRates
        TInt i = sizeof(KRawSampleRates) / sizeof(TUint);
        
        while (i--)
                {
                User::LeaveIfError(aSampleRates.Append(KRawSampleRates[i]));
                }
        }

// get the supported channel number options
void CMMFRawFormatRead::GetSupportedNumChannelsL(RArray<TUint>& aNumChannels)
        {
        aNumChannels.Reset();
        User::LeaveIfError(aNumChannels.Append(KMono));
        User::LeaveIfError(aNumChannels.Append(KStereo));
        }

// get the supported codecs
void CMMFRawFormatRead::GetSupportedDataTypesL(TMediaId aMediaId, RArray<TFourCC>& aDataTypes)
        {
        if (aMediaId.iMediaType != KUidMediaTypeAudio)
                User::Leave(KErrNotSupported);
        aDataTypes.Reset();
        User::LeaveIfError(aDataTypes.Append(KMMFFourCCCodePCM16));
        User::LeaveIfError(aDataTypes.Append(KMMFFourCCCodePCM16B));
        User::LeaveIfError(aDataTypes.Append(KMMFFourCCCodePCMU16));
        User::LeaveIfError(aDataTypes.Append(KMMFFourCCCodeIMAD));
        User::LeaveIfError(aDataTypes.Append(KMMFFourCCCodeIMAS));
        }


//
// CMMFRawFormatWrite
//

// Factory function
CMMFFormatEncode* CMMFRawFormatWrite::NewL(MDataSink* aSink)
        {
        if ((aSink->DataSinkType()==KUidMmfDescriptorSink)||
                        (aSink->DataSinkType()==KUidMmfFileSink))
                {//currently only files and descriptor MDataSources are supported
                CMMFRawFormatWrite* self = new(ELeave)CMMFRawFormatWrite;
                CleanupStack::PushL(self);
                self->ConstructL(aSink);
                CleanupStack::Pop();
                return STATIC_CAST(CMMFFormatEncode*, self);
                }
        else return NULL;
        }

// destructor
CMMFRawFormatWrite::~CMMFRawFormatWrite()
        {
        delete iBuffer;
        delete iConvertBuffer;
        delete iChannelAndSampleRateConverterFactory;
        }
        
// second-phase construction    
void CMMFRawFormatWrite::ConstructL(MDataSink* aSink)
        {
        iClip = aSink;
        //first need to check if sink clip already exists to get settings.
        User::LeaveIfError(iClip->SinkThreadLogon(*this));
        iClip->SinkPrimeL();
        iBuffer = CreateSinkBufferOfSizeL(KDefineIOBufferSize); //512 easiest file size to read
        DoReadL(0);//read from beginning of clip
        if (iBuffer->Data().Size()> 0)
                {
                iClipAlreadyExists = ETrue;
                //There is no header, so data size is the same as the clip size in this case.
                iDataSize = iClipLength = STATIC_CAST(CMMFClip*,iClip)->Size();
                }
        iFrameSize = KFormatDefaultFrameSize;
        }

// from MDataSink

// sink thread attaches
TInt CMMFRawFormatWrite::SinkThreadLogon(MAsyncEventHandler& aEventHandler)
        {//pass through to sink clip
        return(iClip->SinkThreadLogon(aEventHandler));
        }

// helper function: calculates time between frames
void CMMFRawFormatWrite::CalculateFrameTimeInterval()
        {
        if ((iFrameSize) && (iSampleRate) && (iBitsPerSample) && (iChannels))
                {
                iFrameTimeInterval = TTimeIntervalMicroSeconds((iFrameSize*KOneSecondInMicroSeconds)/iSampleRate);
                iFrameTimeInterval = 
                        TTimeIntervalMicroSeconds((iFrameTimeInterval.Int64())/(iBitsPerSample*iChannels));
                iFrameTimeInterval = TTimeIntervalMicroSeconds(iFrameTimeInterval.Int64()*8);
                }
        }

// called if sink setup depends on source
void CMMFRawFormatWrite::Negotiate(MDataSource& aSource)
        {
        if (aSource.DataSourceType() == KUidMmfAudioInput)
                {
                // could query the audio capabilities from DevSound for the settings below
                iSourceSampleRate = 8000; // assume 8KHz for now
                iSourceChannels = 1; //assume mono
                iSourceFourCC.Set(KMMFFourCCCodePCM16); //16 bit PCM
                }
        else if (aSource.DataSourceType() == KUidMmfFormatDecode)
                {//source is a clip so for now set sink settings to match source
                iSourceSampleRate = ((CMMFFormatDecode&)aSource).SampleRate();
                iSourceChannels = ((CMMFFormatDecode&)aSource).NumChannels();
                iSourceFourCC.Set(aSource.SourceDataTypeCode(TMediaId(KUidMediaTypeAudio)));
                iSourceWillSampleConvert = STATIC_CAST(CMMFFormatDecode&, aSource).SourceSampleConvert();
                ((CMMFFormatDecode&)aSource).SuggestSourceBufferSize(iFrameSize); //for now suggest format src takes same buf size as sink??
                //make the start position the end of the clip
                }
        else return;
        //set default sink parameters to be the same as the source
        if (iClipAlreadyExists) iStartPosition = iClipLength;
        if (!iSampleRate) iSampleRate = iSourceSampleRate; //might have already been set by custom command
        if (!iChannels) iChannels = iSourceChannels;
        if (!iBitsPerSample)
                {
                iFourCC.Set(iSourceFourCC);
                if ((iFourCC == KMMFFourCCCodePCM16) ||
                        (iFourCC == KMMFFourCCCodePCM16B) ||
                        (iFourCC == KMMFFourCCCodePCMU16))
                                iBitsPerSample = 16;            
                else if ((iFourCC == KMMFFourCCCodeIMAD) || 
                        (iFourCC == KMMFFourCCCodeIMAS))
                                iBitsPerSample = 4;     
                else 
                                iBitsPerSample = 8; //default to 8
                }
        CalculateFrameTimeInterval();
        }

// Prime the sink to be accessed
void CMMFRawFormatWrite::SinkPrimeL()
        {
        iClip->SinkPrimeL(); //propagate state change down to clip
        CalculateFrameTimeInterval();
        }

// Play the sink
void CMMFRawFormatWrite::SinkPlayL()
        {
        iClip->SinkPlayL(); //propagate state change down to clip
        if ((iChannels != iSourceChannels) || (iSampleRate != iSourceSampleRate) && (!iSourceWillSampleConvert))
                {//the source channels & sample rate don't match the formats - therefore need to do a conversion 
                //currently only pcm16 is supported so return with an error if format not pcm16
                if (iFourCC != KMMFFourCCCodePCM16) User::Leave(KErrNotSupported);
                iChannelAndSampleRateConverterFactory 
                        = new(ELeave)CMMFChannelAndSampleRateConverterFactory;
                iChannelAndSampleRateConverter = 
                        iChannelAndSampleRateConverterFactory->CreateConverterL( iSourceSampleRate, iSourceChannels, 
                                                                                                                                        iSampleRate, iChannels);
                //need to create an intermediate buffer in which to place the converted data
                TUint convertedBufferFrameSize = (iFrameSize*iChannels)/iSourceChannels;
                iConvertBuffer = CreateSinkBufferOfSizeL(convertedBufferFrameSize);
                }
        iFileHasChanged = ETrue; //file will change if we start playing to it
        }

// Pause the sink
void CMMFRawFormatWrite::SinkPauseL()
        {
        iClip->SinkPauseL(); //propagate state change down to clip
        }

// Stop the sink
void CMMFRawFormatWrite::SinkStopL()
        {
        iClip->SinkStopL(); //propagate state change down to clip
        }

// Detach from the sink
void CMMFRawFormatWrite::SinkThreadLogoff()
        {
        iClip->SinkThreadLogoff(); //propagate down to clip
        }

// Called by the CMMFDataPath to add a buffer to a clip
void CMMFRawFormatWrite::EmptyBufferL(CMMFBuffer* aBuffer, MDataSource* aSupplier, TMediaId aMediaId)
        {
        //since raw always contains linear audio the sink buffer size can set the source buffer size

        //check media id &pass onto clip
        if (aMediaId.iMediaType!=KUidMediaTypeAudio) User::Leave(KErrNotSupported); 
        iDataPath = aSupplier;

        // Check we haven't exceeded any set maximum on our clip length
        if (iMaximumClipSize > 0)
                {
                // Find the current clip size
                TInt currentClipLength = STATIC_CAST(CMMFClip*, iClip)->Size();
                TInt bufferSize = aBuffer->BufferSize();
                if ((currentClipLength + bufferSize) >= iMaximumClipSize)
                        User::Leave(KErrEof);
                }

        //assumes first frame is frame 1
        iBufferToEmpty = aBuffer; //save this so it can be returned to datapath
        TInt position = ((aBuffer->FrameNumber()-1)*iFrameSize)+iStartPosition;
        if (position < (TInt)iStartPosition) position = iStartPosition; //can't write before start of header
        if ((iChannelAndSampleRateConverter) && (!iSourceWillSampleConvert))
                {//need to perform channel & sample rate conversion before writing to clip
                iFrameSize = iChannelAndSampleRateConverter->Convert(*(CMMFDataBuffer*)aBuffer,*iConvertBuffer);
                STATIC_CAST(CMMFClip*,iClip)->WriteBufferL(iConvertBuffer, position, this);
                }
        else
                {//no need to convert the data
                STATIC_CAST(CMMFClip*,iClip)->WriteBufferL(aBuffer, position, this);
                }
        iPos = position; //save current write position
        }

// helper function to create buffer of specficed size
CMMFDataBuffer* CMMFRawFormatWrite::CreateSinkBufferOfSizeL(TUint aSize)
        {
        //needs to create source buffer
        CMMFDataBuffer* buffer = CMMFDataBuffer::NewL(aSize);
        buffer->Data().FillZ(aSize);
        iBufferCreated = ETrue;
        return buffer;
        }

// create buffer to receive data
CMMFBuffer* CMMFRawFormatWrite::CreateSinkBufferL(TMediaId aMediaId, TBool &aReference)
        {
        if (aMediaId.iMediaType == KUidMediaTypeAudio) 
                {
                if (!iFrameSize) iFrameSize = KFormatDefaultFrameSize;
                aReference = EFalse;
                return CreateSinkBufferOfSizeL(iFrameSize);
                }
        else User::Leave(KErrNotSupported);
        return NULL;
        }

// gets the codec type
TFourCC CMMFRawFormatWrite::SinkDataTypeCode(TMediaId aMediaId)
        {
        if (aMediaId.iMediaType == KUidMediaTypeAudio) return iFourCC;
        else return TFourCC(); //defaults to 'NULL' fourCC
        }

// sets the codec type
TInt CMMFRawFormatWrite::SetSinkDataTypeCode(TFourCC aSinkFourCC, TMediaId aMediaId)
        {
        if (aMediaId.iMediaType != KUidMediaTypeAudio) return KErrNotSupported;
        else iFourCC = aSinkFourCC;
        
        if ((iFourCC == KMMFFourCCCodePCM16) || 
                (iFourCC == KMMFFourCCCodePCM16B) ||
                (iFourCC == KMMFFourCCCodePCMU16)) 
                        iBitsPerSample = 16;
        else if ((iFourCC == KMMFFourCCCodeIMAD) ||
                (iFourCC == KMMFFourCCCodeIMAS)) 
                        iBitsPerSample = 4;
        else 
                        iBitsPerSample = 8; //default to 8

        return KErrNone;
        }

// helper function to read data from clip
void CMMFRawFormatWrite::DoReadL(TInt aReadPosition)
        {
        STATIC_CAST(CMMFClip*,iClip)->ReadBufferL(iBuffer,aReadPosition);
        }

// helper function to write data to clip
void CMMFRawFormatWrite::DoWriteL(TInt aWritePosition)
        {
        STATIC_CAST(CMMFClip*,iClip)->WriteBufferL(iBuffer,aWritePosition);
        }


// from MDataSource

// called by MDataSink to pass back emptied buffer to the source
void CMMFRawFormatWrite::BufferEmptiedL(CMMFBuffer* aBuffer)
        {
        iDataSize+=aBuffer->BufferSize(); //total bytes written
        iPos += aBuffer->BufferSize(); //total bytes written so far - iPos is not always = iDataSize due to repositions
        if (iMaxPos < iPos) iMaxPos = iPos; //need iMaxPos incase we write data then repos to an earlier pos in the clip
        if (iBufferToEmpty != aBuffer) iDataPath->BufferEmptiedL(iBufferToEmpty); //need to return same buffer
        else iDataPath->BufferEmptiedL(aBuffer);
        }


// from CMMFFormatEncode

// set the number of channels 
TInt CMMFRawFormatWrite::SetNumChannels(TUint aChannels)
        {
        TInt error = KErrNone;
        if ((aChannels ==  KMono)||(aChannels == KStereo)) iChannels = aChannels;
        else error = KErrNotSupported; //only alow one or two channels
        return error;
        }

// set the sample rate
TInt CMMFRawFormatWrite::SetSampleRate(TUint aSampleRate)
        {
        TInt status = KErrNotSupported;
        //we'll iterate through the valid sample table
        TInt i = sizeof(KRawSampleRates) / sizeof(TUint);
                
        while ((i--) && (status != KErrNone))
                {
                if (aSampleRate == KRawSampleRates[i])
                        {
                        iSampleRate = aSampleRate;
                        status = KErrNone;
                        }
                }
        return status;
        }

// get the frame interval
TTimeIntervalMicroSeconds CMMFRawFormatWrite::FrameTimeInterval(TMediaId aMediaId) const
        {
        if (aMediaId.iMediaType == KUidMediaTypeAudio) return iFrameTimeInterval;
        else return TTimeIntervalMicroSeconds(0);
        }

// returns the duration of the source clip
TTimeIntervalMicroSeconds CMMFRawFormatWrite::Duration(TMediaId aMediaId) const
        {
        if ((aMediaId.iMediaType == KUidMediaTypeAudio) 
                && (iDataSize) && (iSampleRate) && (iBitsPerSample) && (iChannels))
                {
                TInt64 clipLength(iDataSize);
                clipLength*=KOneSecondInMicroSeconds;
                TTimeIntervalMicroSeconds duration = TTimeIntervalMicroSeconds(clipLength/iSampleRate);
                duration = 
                        TTimeIntervalMicroSeconds(duration.Int64()/(iBitsPerSample*iChannels));
                duration = TTimeIntervalMicroSeconds(duration.Int64()*8);
                return duration;
                }
        else return TTimeIntervalMicroSeconds(0);
        }

// Calculate and return the number of bytes used for on second of audio.
TInt64 CMMFRawFormatWrite::BytesPerSecond() 
        {
        TInt64 bitsPerSecond = iSampleRate * iBitsPerSample * iChannels ;
        TInt64 bytesPerSecond = bitsPerSecond/8;
        return bytesPerSecond ;
        }

// Shortens the clip from the position specified to the end specified.
void CMMFRawFormatWrite::CropL(TTimeIntervalMicroSeconds aPosition, TBool aToEnd )
        {
        // Does clip have any size to crop
        if (!(STATIC_CAST(CMMFClip*,iClip)->Size())) User::Leave(KErrNotFound); //no clip to crop or clip is 0 bytes.


        // Is aPosition between the start and the end?
        if ( ( aPosition < TTimeIntervalMicroSeconds(0) ) || ( aPosition >= Duration( KUidMediaTypeAudio) ) ) 
                User::Leave( KErrArgument ) ;

        // Convert aPostion to cropPosition in bytes

        TInt64 cropPosition64 = 
                TInt64( ( aPosition.Int64() * iSampleRate * (iBitsPerSample/8) * iChannels ) /KOneSecondInMicroSeconds);
        TUint cropPosition = I64INT(cropPosition64);

        // Does cropPosition need adjustment to retain integrity?  (assume not)

        TUint dataSize ;  // This will be the size of the data left after cropping.

        if ( !aToEnd )
                {
                // Shift the data physically
                // move the data in blocks
                // Create a CMMFDataBuffer and use CMMFClip to shift the data
                dataSize = iMaxPos - cropPosition ;
                if (( dataSize > 0 ) && (aPosition != TTimeIntervalMicroSeconds(0)))
                        {
                        TUint bufSize = ( dataSize < KDefineIOBufferSize ? dataSize : KDefineIOBufferSize ) ; //max bufSize 512
                        CMMFDataBuffer* buffer = CMMFDataBuffer::NewL(bufSize) ;
                        CleanupStack::PushL( buffer ) ;

                        TUint rPos = cropPosition ; // read position
                        TUint wPos = 0;
                        TInt dataToShift = ETrue ;
                        while ( dataToShift )
                                {
                                STATIC_CAST( CMMFClip*, iClip )->ReadBufferL( buffer, rPos ) ;  // synchronous calls
                                STATIC_CAST( CMMFClip*, iClip )->WriteBufferL( buffer, wPos ) ;
                                if ( rPos > iMaxPos ) 
                                        dataToShift = EFalse ;  // past the end:  Done
                                else
                                        { // shift the pointers
                                        rPos += bufSize ;
                                        wPos += bufSize ;
                                        }
                                }// while data to shift
                        CleanupStack::PopAndDestroy( ) ; // buffer
                        }// if data to shift
                }// crop to start
        else // crop to end
                dataSize = cropPosition ;

        iDataSize = dataSize ;
        iMaxPos = dataSize ;

        // Do the physical chop
        if ( iClip->DataSinkType() == KUidMmfFileSink )
                {
                STATIC_CAST( CMMFFile*, iClip )->FileL().SetSize( iMaxPos ) ;
                iClipLength = iMaxPos; 
                }
        }

// get the supported sample rates
void CMMFRawFormatWrite::GetSupportedSampleRatesL(RArray<TUint>& aSampleRates)
        {
        aSampleRates.Reset();

        // Iterate through the valid sample table and append each value to aSampleRates
        TInt i = sizeof(KRawSampleRates) / sizeof(TUint);
        
        while (i--)
                {
                User::LeaveIfError(aSampleRates.Append(KRawSampleRates[i]));
                }
        }

// get the supported channel number options
void CMMFRawFormatWrite::GetSupportedNumChannelsL(RArray<TUint>& aNumChannels)
        {
        aNumChannels.Reset();
        User::LeaveIfError(aNumChannels.Append(KMono));
        User::LeaveIfError(aNumChannels.Append(KStereo));
        }

// set maximum clip size
void CMMFRawFormatWrite::SetMaximumClipSize(TInt aBytes)
        {
        iMaximumClipSize = aBytes;
        }

// get the supported codecs
void CMMFRawFormatWrite::GetSupportedDataTypesL(TMediaId aMediaId, RArray<TFourCC>& aDataTypes)
        {
        if (aMediaId.iMediaType != KUidMediaTypeAudio)
                User::Leave(KErrNotSupported);
        aDataTypes.Reset();
        User::LeaveIfError(aDataTypes.Append(KMMFFourCCCodePCM16));
        User::LeaveIfError(aDataTypes.Append(KMMFFourCCCodePCM16B));
        User::LeaveIfError(aDataTypes.Append(KMMFFourCCCodePCMU16));
        User::LeaveIfError(aDataTypes.Append(KMMFFourCCCodeIMAD));
        User::LeaveIfError(aDataTypes.Append(KMMFFourCCCodeIMAS));
        }


// __________________________________________________________________________
// Exported proxy for instantiation method resolution
// Define the interface UIDs

const TImplementationProxy ImplementationTable[] = 
        {
                IMPLEMENTATION_PROXY_ENTRY(KRawDecoder, CMMFRawFormatRead::NewL),
                IMPLEMENTATION_PROXY_ENTRY(KRawEncoder, CMMFRawFormatWrite::NewL)
        };

EXPORT_C const TImplementationProxy* ImplementationGroupProxy(TInt& aTableCount)
        {
        aTableCount = sizeof(ImplementationTable) / sizeof(TImplementationProxy);

        return ImplementationTable;
        }

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