MpegAudioStream.cxx

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/*
 * Copyright (c) 2004 MUSIC TECHNOLOGY GROUP (MTG)
 *                         UNIVERSITAT POMPEU FABRA
 *
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#include "MpegAudioStream.hxx"
#include "AudioFile.hxx"
#include "Assert.hxx"
#include <iostream>

namespace CLAM
{

namespace AudioCodecs
{
        // A reasonable multiple of four
        const TSize MpegAudioStream::mMaxDecodedBlockSize = 8192;

        MpegAudioStream::MpegAudioStream()
                : mpHandle( NULL )
        {
        }

        MpegAudioStream::MpegAudioStream( const AudioFile& file )
                : mpHandle( NULL )
        {
                SetFOI( file );
        }

        MpegAudioStream::~MpegAudioStream()
        {
                
                if ( mpHandle )
                {
                        if ( fclose(mpHandle) )
                        {
                                std::string msgString = "Could not close ";
                                msgString += mName;

                                CLAM_ASSERT( false, msgString.c_str() );
                        }                       
                }
                
        }
        
        void MpegAudioStream::SetFOI( const AudioFile& file )
        {
                AudioFileToNative( file );              
        }

        void MpegAudioStream::AudioFileToNative( const AudioFile& file )
        {
                mName = file.GetLocation();
                mEncodedSampleRate = (int)file.GetHeader().GetSampleRate();
                mEncodedChannels = (int)file.GetHeader().GetChannels();

                mDecodeBuffer.resize( mEncodedChannels );
        }

        void MpegAudioStream::PrepareReading()
        {
                mpHandle = fopen( mName.c_str(), "rb");

                if ( !mpHandle )
                {
                        std::string msgString = "Could not open ";
                        msgString += mName;
                        msgString += " for reading!";

                        CLAM_ASSERT( false, msgString.c_str() );
                        
                }

                mBitstream.Init( mpHandle );

                SetChannels( mEncodedChannels );
                MarkAllChannelsAsConsumed();

                mSamplesDecoded = 0;
                mSamplesTransferred = 0;
        }

        void MpegAudioStream::PrepareWriting()
        {
                CLAM_ASSERT( false, "CLAM does not encode Mpeg Audio!!!");
        }

        void MpegAudioStream::PrepareReadWrite()
        {
                CLAM_ASSERT( false, "CLAM does not encode Mpeg Audio!!!");
        }

        void MpegAudioStream::Dispose()
        {
                mBitstream.Finish();
        }

        void MpegAudioStream::DiskToMemoryTransfer()
        {
                unsigned samplesToRead = mInterleavedData.Size()/mEncodedChannels;

                while( mDecodeBuffer[0].size() < samplesToRead
                       && mBitstream.NextFrame() )
                {
                        mBitstream.SynthesizeCurrent();
                        
                        CLAM_ASSERT( mEncodedChannels == MAD_NCHANNELS( &mBitstream.CurrentFrame().header ),
                                     "This frame hasn't mEncodedChannels channels!" );
                        
                        CLAM_ASSERT( mEncodedChannels == mBitstream.CurrentSynthesis().pcm.channels,
                                     "Synthesis result does not have the expected number of channels" );
                        
                        TSize samplesDecodedThisTime = mBitstream.CurrentSynthesis().pcm.length;
                        
                        for( int i = 0; i < mEncodedChannels; i++ )
                        {
                                mad_fixed_t* channelData = mBitstream.CurrentSynthesis().pcm.samples[i];
                                
                                mDecodeBuffer[i].insert( mDecodeBuffer[i].end(),
                                                         channelData,
                                                         channelData + samplesDecodedThisTime );
                        }
                        
                        mSamplesDecoded += mBitstream.CurrentSynthesis().pcm.length;

                }
                
                mFramesLastRead = mDecodeBuffer[0].size();

                if ( !mDecodeBuffer[0].empty() )
                {

                        for ( int i = 0; i < mEncodedChannels; i++ )
                                if ( mDecodeBuffer[i].size() < samplesToRead )
                                {
                                        mDecodeBuffer[i].insert( mDecodeBuffer[i].end(),
                                                                 samplesToRead - mDecodeBuffer[i].size(),
                                                                 mad_fixed_t(0) );
                                        
                                }
                        
                        ConsumeDecodedSamples();
                }

                mEOFReached = mBitstream.EOS() && mDecodeBuffer[0].empty();
        }

        void MpegAudioStream::ConsumeDecodedSamples()
        {
                TSize samplesToRead = mInterleavedData.Size()/mEncodedChannels;

                for ( int i = 0; i < mEncodedChannels; i++ )
                {
                        TIndex currOffset = 0;

                        for ( std::deque<mad_fixed_t>::iterator j = mDecodeBuffer[i].begin();
                              currOffset < mInterleavedData.Size(); 
                              j++, currOffset+=mEncodedChannels )
                        {
                                double sampleValue = mad_f_todouble(*j);

                                // :TODO: Finding a nicer way to clamp things
                                // to the -1,1 could be necessary
                                // clipping
                                if ( sampleValue > 1.0 )
                                        sampleValue = 1.0;
                                else if ( sampleValue < -1.0 )
                                        sampleValue = -1.0;
                                        
                                
                                mInterleavedData[ currOffset + i ] = TData(sampleValue);
                        }
                        
                        mDecodeBuffer[i].erase( mDecodeBuffer[i].begin(),
                                                mDecodeBuffer[i].begin() + samplesToRead );
                }

                mSamplesTransferred += samplesToRead;
                

        }

        void MpegAudioStream::MemoryToDiskTransfer()
        {
                CLAM_ASSERT( false, "CLAM does not encode Mpeg Audio!!!");
        }
}
        
}

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