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( const AudioFile& file )
                : mpHandle( NULL )
        {
                mName = file.GetLocation();
                mEncodedSampleRate = (int)file.GetHeader().GetSampleRate();
                mChannels = (int)file.GetHeader().GetChannels();
                mDecodeBuffer.resize( mChannels );
        }

        MpegAudioStream::~MpegAudioStream()
        {
                if ( not mpHandle ) return;
                fclose(mpHandle);
        }
        
        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 );

                mSamplesDecoded = 0;
                mFramePosition = 0;
                _mp3Frame = 0;
        }

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

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

        void MpegAudioStream::DiskToMemoryTransfer()
        {
                unsigned nFrames = mInterleavedData.size()/mChannels;
                while( mDecodeBuffer[0].size() < nFrames
                       && mBitstream.NextFrame() )
                {
                        unsigned long filePos = mBitstream.CurrentFrameFileOffset();
                        if (_mp3Frame>=_seekCache.size())
                                _seekCache.push_back(filePos);
                        else
                        {
/*
                                std::cout
                                        << "Mp3 frame "
                                        << mFramePosition << " "
                                        << _mp3Frame << " R:"
                                        << filePos << " E:"
                                        << _seekCache[_mp3Frame] << " R-E:"
                                        << int(filePos)-int(_seekCache[_mp3Frame])
                                        << std::endl;
*/
                                CLAM_WARNING(filePos==_seekCache[_mp3Frame],
                                        "MP3 indexing not matching");
                        }
                        mBitstream.SynthesizeCurrent();
                        
                        CLAM_ASSERT( mChannels == MAD_NCHANNELS( &mBitstream.CurrentFrame().header ),
                                     "MpegAudioStream: A frame had not the expected channels." );
                        CLAM_ASSERT( mChannels == mBitstream.CurrentSynthesis().pcm.channels,
                                     "MpegAudioStream: Synthesis result had not the expected number of channels" );
                        
                        TSize samplesDecodedThisTime = mBitstream.CurrentSynthesis().pcm.length;
                        for(unsigned i = 0; i < mChannels; i++ )
                        {
                                mad_fixed_t* channelData = mBitstream.CurrentSynthesis().pcm.samples[i];
                                mDecodeBuffer[i].insert( mDecodeBuffer[i].end(),
                                                         channelData,
                                                         channelData + samplesDecodedThisTime );
                        }
                        mSamplesDecoded += samplesDecodedThisTime;
                        _mp3Frame++;
                }
                
                mFramesLastRead = mDecodeBuffer[0].size();
                mEOFReached = mBitstream.EOS() && mDecodeBuffer[0].empty();

                if (mDecodeBuffer[0].empty()) return;

                for (unsigned i = 0; i < mChannels; i++ )
                {
                        if ( mDecodeBuffer[i].size() < nFrames )
                        {
                                mDecodeBuffer[i].insert(
                                        mDecodeBuffer[i].end(),
                                        nFrames - mDecodeBuffer[i].size(),
                                        mad_fixed_t(0) );
                        }
                }
                ConsumeDecodedSamples();
        }

        void MpegAudioStream::ConsumeDecodedSamples()
        {
                unsigned nFrames = mInterleavedData.size()/mChannels;
                for (unsigned i = 0; i < mChannels; i++ )
                {
                        unsigned currOffset = 0;
                        for ( std::deque<mad_fixed_t>::iterator j = mDecodeBuffer[i].begin();
                              currOffset < mInterleavedData.size(); 
                              j++, currOffset+=mChannels )
                        {
                                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() + nFrames );
                }
                mFramePosition += nFrames;
        }

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

        void MpegAudioStream::SeekTo(unsigned long framePosition)
        {
                // Warning: two 'frames' here, mp3's and AudioStream's (items*channels)
                if (framePosition==mFramePosition) return;
                unsigned mp3FrameSize = 32*MAD_NSBSAMPLES(&mBitstream.CurrentFrame().header);
                unsigned targetMp3Frame = framePosition/mp3FrameSize;
                std::cout << "targetMp3Frame: " << targetMp3Frame << std::endl;
                // TODO: Jumps beyond the last played frame are too expensive to be frame accurate
                unsigned maxForwarJump = _seekCache.size()+100;
                if (targetMp3Frame>maxForwarJump) targetMp3Frame=maxForwarJump;
                if (targetMp3Frame>=_seekCache.size())
                {
                        // Construct the index beyond current limits, til the target frame
                        fseek(mpHandle, _seekCache[_seekCache.size()-2], SEEK_SET);
                        mBitstream.Init();
                        for (unsigned mp3Frame=_seekCache.size();
                                mp3Frame<=targetMp3Frame; mp3Frame++)
                        {
                                if (not mBitstream.NextFrame()) return;
                                unsigned long filePos = mBitstream.CurrentFrameFileOffset();
/*
                                std::cout << "fwd "
                                        << _seekCache.back() << " "
                                        << filePos << " " 
                                        << int(filePos)-_seekCache.back() << std::endl;
*/
                                if (filePos<=_seekCache.back()) continue; // filtering already done
                                _seekCache.push_back(filePos);
                        }
                }
                unsigned skip = targetMp3Frame>4?3:0;
                unsigned jumpingFrame = targetMp3Frame-skip;
                std::cout << "jumpingFrame:" << jumpingFrame << std::endl;
                fseek(mpHandle, _seekCache[jumpingFrame], SEEK_SET);
                mBitstream.Init();
                _mp3Frame = targetMp3Frame;
                // TODO: Because the already buffered bins this is not true
                mFramePosition = mp3FrameSize * _mp3Frame;
                if (targetMp3Frame == 0) return;
                unsigned long previousFrameFilePos = _seekCache[targetMp3Frame-1];
                while (true)
                {
                        mBitstream.NextFrame();
                        unsigned long filePos = mBitstream.CurrentFrameFileOffset();
/*
                        std::cout << "seek "
                                << filePos << " "
                                << previousFrameFilePos << std::endl;
*/
                        if (filePos >= previousFrameFilePos) break;
                }
                mBitstream.SynthesizeCurrent();

                unsigned long filePos = mBitstream.CurrentFrameFileOffset();
/*
                std::cout << "Jump n target: " 
                        << _mp3Frame << " "
                        << targetMp3Frame << " "
                        << filePos << " "
                        << _seekCache[targetMp3Frame-1]
                        << std::endl;
*/
                // TODO: Sample accurate seek (now it is frame accurate)
/*
                CLAM_ASSERT(_seekCache[targetMp3Frame-1]==filePos,
                        "File postions don't match");
                CLAM_ASSERT(_mp3Frame==targetMp3Frame, "Seek mp3 frames don't match");
                // We should synthesize the previous frame to the one we want.
*/      }
}
        
}