MpegBitstream.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 "MpegBitstream.hxx"
#include "Assert.hxx"
#include <cstring>
#include <iostream>
#include <sstream>
#include <iomanip>

namespace CLAM
{

namespace AudioCodecs
{
        // MRJ: This number was extracted from Underbit's own
        // mp3 player code ( mad-0.14.2b2, player.c:86 ). As they
        // say: 40000 bytes is worth 2.5 secs of audio on a stream
        // with 128 kpbs, 1s with 320 kbps
        const int MpegBitstream::mInputBufferSize = 5*8192;
        
        // Taken from alsaplayer
    static std::string MadError(enum mad_error error)
        {
                switch (error) {
                        case MAD_ERROR_BUFLEN:
                        case MAD_ERROR_BUFPTR:
                                /* these errors are handled specially and/or should not occur */
                                break;

                        case MAD_ERROR_NOMEM:        return ("not enough memory");
                        case MAD_ERROR_LOSTSYNC:     return ("lost synchronization");
                        case MAD_ERROR_BADLAYER:     return ("reserved header layer value");
                        case MAD_ERROR_BADBITRATE:   return ("forbidden bitrate value");
                        case MAD_ERROR_BADSAMPLERATE:    return ("reserved sample frequency value");
                        case MAD_ERROR_BADEMPHASIS:  return ("reserved emphasis value");
                        case MAD_ERROR_BADCRC:       return ("CRC check failed");
                        case MAD_ERROR_BADBITALLOC:  return ("forbidden bit allocation value");
                        case MAD_ERROR_BADSCALEFACTOR:   return ("bad scalefactor index");
                        case MAD_ERROR_BADFRAMELEN:  return ("bad frame length");
                        case MAD_ERROR_BADBIGVALUES:     return ("bad big_values count");
                        case MAD_ERROR_BADBLOCKTYPE:     return ("reserved block_type");
                        case MAD_ERROR_BADSCFSI:     return ("bad scalefactor selection info");
                        case MAD_ERROR_BADDATAPTR:   return ("bad main_data_begin pointer");
                        case MAD_ERROR_BADPART3LEN:  return ("bad audio data length");
                        case MAD_ERROR_BADHUFFTABLE:     return ("bad Huffman table select");
                        case MAD_ERROR_BADHUFFDATA:  return ("Huffman data overrun");
                        case MAD_ERROR_BADSTEREO:    return ("incompatible block_type for JS");
                        default:;
                }
                std::ostringstream os;
                os << "error 0x" << std::setbase(16) << std::setfill('4') << std::setw(4) << error;
                return os.str();
        }

        MpegBitstream::MpegBitstream()
                : mpFile(NULL)
        {
                mInputBuffer = new unsigned char[mInputBufferSize];
        }
        
        MpegBitstream::~MpegBitstream()
        {
                if ( mInputBuffer )
                        delete [] mInputBuffer;
        }

        void MpegBitstream::Init( FILE* fp )
        {
                mpFile = fp;
                Init();
        }

        void MpegBitstream::Init()
        {
                mad_stream_init( &mBitstream );
                mad_frame_init( &mCurrentFrame );
                mad_synth_init( &mMpegSynth );
                mad_timer_reset( &mStreamTimer );
                mFatalError = false;
        }

        TTime MpegBitstream::Finish()
        {
                mad_synth_finish( &mMpegSynth );
                mad_frame_finish( &mCurrentFrame );
                mad_stream_finish( &mBitstream );

                return (TTime)mad_timer_count( mStreamTimer, MAD_UNITS_MILLISECONDS );
        }

        bool MpegBitstream::EOS()
        {
                if ( feof( mpFile ) ) // no more frames
                        return true;
                return false;
        }

        bool MpegBitstream::FatalError()
        {
                return mFatalError || ferror(mpFile)!=0;
        }

        bool MpegBitstream::EnsureEnoughBufferData()
        {
                bool firstFrameAfterSeek = mBitstream.buffer == NULL;
                bool lastDecodeNeededMoreData = mBitstream.error == MAD_ERROR_BUFLEN;
                if ( not firstFrameAfterSeek and not lastDecodeNeededMoreData) return true;

                TSize remaining = 0;
                if (not firstFrameAfterSeek)
                {
                        remaining = mBitstream.bufend - mBitstream.next_frame;
                        memmove( mInputBuffer, mBitstream.next_frame, remaining );
                }
                unsigned char * readStart = mInputBuffer + remaining;
                TSize readSize = mInputBufferSize - remaining;
                mBufferFileOffset = ftell(mpFile) - remaining;
                TSize actuallyRead = fread( readStart, sizeof(unsigned char), readSize, mpFile );

                if ( actuallyRead == 0 ) return false; // Eof or ferror
                // Less bytes than expected were read, add buffer guard
                if ( actuallyRead < readSize )
                {
                        CLAM_ASSERT( readStart + actuallyRead + MAD_BUFFER_GUARD <= mInputBuffer + mInputBufferSize,
                                "Whoops! no room left for buffer guard bytes" );
                        // Add mad buffer guard
                        memset(readStart+actuallyRead, 0, MAD_BUFFER_GUARD);
                        actuallyRead += MAD_BUFFER_GUARD;
                }

                mad_stream_buffer( &mBitstream, mInputBuffer, actuallyRead+remaining );
                mBitstream.error = MAD_ERROR_NONE; // DGG: Why that?
                return true;
        }

        bool MpegBitstream::NextFrame()
        {
                while( not ferror(mpFile) )
                {
                        if (not EnsureEnoughBufferData()) return false;

                        int error = mad_frame_decode(&mCurrentFrame, &mBitstream);
                        if (error != -1) 
                        {
                                // frame was decoded right
                                // we add this frame duration to the bitstream internal timer
                                mad_timer_add( &mStreamTimer, mCurrentFrame.header.duration );
                                return true;
                        }

                        if ( MAD_RECOVERABLE( mBitstream.error ) )
                        {
//                              std::cerr << "MP3 recoverable error ignored: " << MadError(mBitstream.error) << std::endl;
                                continue; // Recoverable error, ignore
                        }
                        if ( mBitstream.error == MAD_ERROR_BUFLEN )     continue; // Not enough data, take more
                        // Some fatal error happened!
                        mFatalError = true;
                        std::cerr << "MP3 fatal error: " << MadError(mBitstream.error) << std::endl;
                        return false;
                }
                return false; // file error
        }

        unsigned long MpegBitstream::CurrentFrameFileOffset() const
        {
                unsigned long frameOffset = mBitstream.this_frame - mInputBuffer;
                return mBufferFileOffset + frameOffset;
        }

        void MpegBitstream::SynthesizeCurrent()
        {
                mad_synth_frame( &mMpegSynth, &mCurrentFrame );
        }

        struct mad_frame& MpegBitstream::CurrentFrame()
        {
                return mCurrentFrame;
        }

        struct mad_synth& MpegBitstream::CurrentSynthesis()
        {
                return mMpegSynth;
        }
        
}

}