path: root/src/sound/PeakFile.cpp

// -*- c-indentation-style:"stroustrup" c-basic-offset: 4 -*- /*
/*
  Rosegarden
  A sequencer and musical notation editor.
 
  This program is Copyright 2000-2008
  Guillaume Laurent   <glaurent@telegraph-road.org>,
  Chris Cannam        <cannam@all-day-breakfast.com>,
  Richard Bown        <bownie@bownie.com>
 
  The moral right of the authors to claim authorship of this work
  has been asserted.
 
  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.  See the file
  COPYING included with this distribution for more information.
*/

#include <cmath>
#include <cstdlib>
#include <kapplication.h>

#include <tqdatetime.h>
#include <tqstringlist.h>
#include <tqpalette.h>
#include <kapp.h>

#include "PeakFile.h"
#include "AudioFile.h"
#include "Profiler.h"

using std::cout;
using std::cerr;
using std::endl;

//#define DEBUG_PEAKFILE 1
//#define DEBUG_PEAKFILE_BRIEF 1
//#define DEBUG_PEAKFILE_CACHE 1

#ifdef DEBUG_PEAKFILE
#define DEBUG_PEAKFILE_BRIEF 1
#endif

namespace Rosegarden
{

PeakFile::PeakFile(AudioFile *audioFile):
        SoundFile(audioFile->getPeakFilename()),
        m_audioFile(audioFile),
        m_version( -1),                          // -1 defines new file - start at 0
        m_format(1),                            // default is 8-bit peak format
        m_pointsPerValue(0),
        m_blockSize(256),                       // default block size is 256 samples
        m_channels(0),
        m_numberOfPeaks(0),
        m_positionPeakOfPeaks(0),
        m_offsetToPeaks(0),
        m_modificationTime(TQDate(1970, 1, 1), TQTime(0, 0, 0)),
        m_chunkStartPosition(0),
        m_lastPreviewStartTime(0, 0),
        m_lastPreviewEndTime(0, 0),
        m_lastPreviewWidth( -1),
        m_lastPreviewShowMinima(false)
{}

PeakFile::~PeakFile()
{}

bool
PeakFile::open()
{
    // Set the file size
    //
    TQFileInfo info(TQString(m_fileName.c_str()));
    m_fileSize = info.size();

    // If we're already open then don't open again
    //
    if (m_inFile && m_inFile->is_open())
        return true;

    // Open
    //
    m_inFile = new std::ifstream(m_fileName.c_str(),
                                 std::ios::in | std::ios::binary);
    // Check we're open
    //
    if (!(*m_inFile))
        return false;

    try {
        parseHeader();
    } catch (BadSoundFileException s) {

#ifdef DEBUG_PEAKFILE
        cerr << "PeakFile::open - EXCEPTION \"" << s.getMessage() << "\""
        << endl;
#endif

        return false;
    }

    return true;
}

void
PeakFile::parseHeader()
{
    if (!(*m_inFile))
        return ;

    m_inFile->seekg(0, std::ios::beg);

    // get full header length
    //
    std::string header = getBytes(128);

#if (__GNUC__ < 3)

    if (header.compare(AUDIO_BWF_PEAK_ID, 0, 4) != 0)
#else

    if (header.compare(0, 4, AUDIO_BWF_PEAK_ID) != 0)
#endif

    {
        throw(BadSoundFileException(m_fileName, "PeakFile::parseHeader - can't find LEVL identifier"));
    }

    int length = getIntegerFromLittleEndian(header.substr(4, 4));

    // Get the length of the header minus the first 8 bytes
    //
    if (length == 0)
        throw(BadSoundFileException(m_fileName, "PeakFile::parseHeader - can't get header length"));

    // Get the file information
    //
    m_version = getIntegerFromLittleEndian(header.substr(8, 4));
    m_format = getIntegerFromLittleEndian(header.substr(12, 4));
    m_pointsPerValue = getIntegerFromLittleEndian(header.substr(16, 4));
    m_blockSize = getIntegerFromLittleEndian(header.substr(20, 4));
    m_channels = getIntegerFromLittleEndian(header.substr(24, 4));
    m_numberOfPeaks = getIntegerFromLittleEndian(header.substr(28, 4));
    m_positionPeakOfPeaks = getIntegerFromLittleEndian(header.substr(32, 4));

    // Read in date string and convert it up to TQDateTime
    //
    TQString dateString = TQString(header.substr(40, 28).c_str());

    TQStringList dateTime = TQStringList::split(":", dateString);

    m_modificationTime.setDate(TQDate(dateTime[0].toInt(),
                                     dateTime[1].toInt(),
                                     dateTime[2].toInt()));

    m_modificationTime.setTime(TQTime(dateTime[3].toInt(),
                                     dateTime[4].toInt(),
                                     dateTime[5].toInt(),
                                     dateTime[6].toInt()));

    //printStats();

}

void
PeakFile::printStats()
{
    cout << endl;
    cout << "STATS for PeakFile \"" << m_fileName << "\"" << endl
    << "-----" << endl << endl;

    cout << "  VERSION = " << m_version << endl
    << "  FORMAT  = " << m_format << endl
    << "  BYTES/VALUE = " << m_pointsPerValue << endl
    << "  BLOCKSIZE   = " << m_blockSize << endl
    << "  CHANNELS    = " << m_channels << endl
    << "  PEAK FRAMES = " << m_numberOfPeaks << endl
    << "  PEAK OF PKS = " << m_positionPeakOfPeaks << endl
    << endl;

    cout << "DATE" << endl
    << "----" << endl << endl
    << "  YEAR    = " << m_modificationTime.date().year() << endl
    << "  MONTH   = " << m_modificationTime.date().month() << endl
    << "  DAY     = " << m_modificationTime.date().day() << endl
    << "  HOUR    = " << m_modificationTime.time().hour() << endl
    << "  MINUTE  = " << m_modificationTime.time().minute()
    << endl
    << "  SECOND  = " << m_modificationTime.time().second()
    << endl
    << "  MSEC    = " << m_modificationTime.time().msec()
    << endl << endl;
}

bool
PeakFile::write()
{
    return write(5); // default update every 5%
}

bool
PeakFile::write(unsigned short updatePercentage)
{
    if (m_outFile) {
        m_outFile->close();
        delete m_outFile;
    }

    // Attempt to open AudioFile so that we can extract sample data
    // for preview file generation
    //
    try {
        if (!m_audioFile->open())
            return false;
    } catch (BadSoundFileException e) {
#ifdef DEBUG_PEAKFILE
        std::cerr << "PeakFile::write - \"" << e.getMessage() << "\"" << std::endl;
#endif

        return false;
    }

    // create and test that we've made it
    m_outFile = new std::ofstream(m_fileName.c_str(),
                                  std::ios::out | std::ios::binary);
    if (!(*m_outFile))
        return false;

    // write out the header
    writeHeader(m_outFile);

    // and now the peak values
    writePeaks(updatePercentage, m_outFile);

    return true;
}

// Close the peak file and tidy up
//
void
PeakFile::close()
{
    // Close any input file handle
    //
    if (m_inFile && m_inFile->is_open()) {
        m_inFile->close();
        delete m_inFile;
        m_inFile = 0;
    }

    if (m_outFile == 0)
        return ;

    // Seek to start of chunk
    //
    m_outFile->seekp(m_chunkStartPosition, std::ios::beg);

    // Seek to size field at set it
    //
    m_outFile->seekp(4, std::ios::cur);
    putBytes(m_outFile, getLittleEndianFromInteger(m_bodyBytes + 120, 4));

    // Seek to format and set it (m_format is only set at the
    // end of writePeaks()
    //
    m_outFile->seekp(4, std::ios::cur);
    putBytes(m_outFile, getLittleEndianFromInteger(m_format, 4));

    // Seek to number of peak frames and write value
    //
    m_outFile->seekp(12, std::ios::cur);
    putBytes(m_outFile,
             getLittleEndianFromInteger(m_numberOfPeaks, 4));

    // Peak of peaks
    //
    putBytes(m_outFile,
             getLittleEndianFromInteger(m_positionPeakOfPeaks, 4));

    // Seek to date field
    //
    m_outFile->seekp(4, std::ios::cur);

    // Set modification time to now
    //
    m_modificationTime = m_modificationTime.tqcurrentDateTime();

    TQString fDate;
    fDate.sprintf("%04d:%02d:%02d:%02d:%02d:%02d:%03d",
                  m_modificationTime.date().year(),
                  m_modificationTime.date().month(),
                  m_modificationTime.date().day(),
                  m_modificationTime.time().hour(),
                  m_modificationTime.time().minute(),
                  m_modificationTime.time().second(),
                  m_modificationTime.time().msec());

    std::string dateString(fDate.ascii());

    // Pad with spaces to make up to 28 bytes long and output
    //
    dateString += "     ";
    putBytes(m_outFile, dateString);

    // Ok, now close and tidy up
    //
    m_outFile->close();
    delete m_outFile;
    m_outFile = 0;
}

// If the audio file is more recently modified that the modification time
// on this peak file then we're invalid.  The action to rectify this is
// usually to regenerate the peak data.
//
bool
PeakFile::isValid()
{
    if (m_audioFile->getModificationDateTime() > m_modificationTime)
        return false;

    return true;
}

bool
PeakFile::writeToHandle(std::ofstream *file,
                        unsigned short /*updatePercentage*/)
{
    // Remember the position where we pass in the ofstream pointer
    // so we can return there to write close() information.
    //
    m_chunkStartPosition = file->tellp();

    return false;
}

// Build up a header string and then pump it out to the file handle
//
void
PeakFile::writeHeader(std::ofstream *file)
{
    if (!file || !(*file))
        return ;

    std::string header;

    // The "levl" identifer for this chunk
    //
    header += AUDIO_BWF_PEAK_ID;

    // Add a four byte version of the size of the header chunk (120
    // bytes from this point onwards)
    //
    header += getLittleEndianFromInteger(120, 4);

    // A four byte version number (incremented every time)
    //
    header += getLittleEndianFromInteger(++m_version, 4);

    // Format of the peak points - 1 = unsigned char
    //                             2 = unsigned short
    //
    header += getLittleEndianFromInteger(m_format, 4);

    // Points per value          - 1 = 1 peak and has vertical about x-axis
    //                             2 = 2 peaks so differs above and below x-axis
    //
    // .. hardcode to 2 for the mo
    m_pointsPerValue = 2;
    header += getLittleEndianFromInteger(m_pointsPerValue, 4);

    // Block size - default and recommended is 256
    //
    header += getLittleEndianFromInteger(m_blockSize, 4);

    // Set channels up if they're currently empty
    //
    if (m_channels == 0 && m_audioFile)
        m_channels = m_audioFile->getChannels();

    // Peak channels - same as AudioFile channels
    //
    header += getLittleEndianFromInteger(m_channels, 4);

    // Number of peak frames - we write this at close() and so
    // for the moment put spacing 0's in.
    header += getLittleEndianFromInteger(0, 4);

    // Position of peak of peaks - written at close()
    //
    header += getLittleEndianFromInteger(0, 4);

    // Offset to start of peaks - usually the total size of this header
    //
    header += getLittleEndianFromInteger(128, 4);

    // Creation timestamp - fill in on close() so just use spacing
    // of 28 bytes for the moment.
    //
    header += getLittleEndianFromInteger(0, 28);

    // reserved space - 60 bytes
    header += getLittleEndianFromInteger(0, 60);

    //cout << "HEADER LENGTH = " << header.length() << endl;

    // write out the header
    //
    putBytes(file, header);
}

bool
PeakFile::scanToPeak(int peak)
{
    if (!m_inFile)
        return false;

    if (!m_inFile->is_open())
        return false;

    // Scan to start of chunk and then seek to peak number
    //
    ssize_t pos = (ssize_t)m_chunkStartPosition + 128 +
                  peak * m_format * m_channels * m_pointsPerValue;

    ssize_t off = pos - m_inFile->tellg();

    if (off == 0) {
        return true;
    } else if (off < 0) {
        //	std::cerr << "PeakFile::scanToPeak: warning: seeking backwards for peak " << peak << " (" << m_inFile->tellg() << " -> " << pos << ")" << std::endl;
        m_inFile->seekg(pos);
    } else {
        m_inFile->seekg(off, std::ios::cur);
    }

    // Ensure we re-read the input buffer if we're
    // doing buffered reads as it's now meaningless
    //
    m_loseBuffer = true;

    if (m_inFile->eof()) {
        m_inFile->clear();
        return false;
    }

    return true;
}

bool
PeakFile::scanForward(int numberOfPeaks)
{
    if (!m_inFile)
        return false;

    if (!m_inFile->is_open())
        return false;

    // Seek forward and number of peaks
    //
    m_inFile->seekg(numberOfPeaks * m_format * m_channels * m_pointsPerValue,
                    std::ios::cur);

    // Ensure we re-read the input buffer
    m_loseBuffer = true;

    if (m_inFile->eof()) {
        m_inFile->clear();
        return false;
    }

    return true;
}


void
PeakFile::writePeaks(unsigned short /*updatePercentage*/,
                     std::ofstream *file)
{
    if (!file || !(*file))
        return ;
    m_keepProcessing = true;

#ifdef DEBUG_PEAKFILE

    cout << "PeakFile::writePeaks - calculating peaks" << endl;
#endif

    // Scan to beginning of audio data
    m_audioFile->scanTo(RealTime(0, 0));

    // Store our samples
    //
    std::vector<std::pair<int, int> > channelPeaks;
    std::string samples;
    unsigned char *samplePtr;

    int sampleValue;
    int sampleMax = 0 ;
    int sampleFrameCount = 0;

    int channels = m_audioFile->getChannels();
    int bytes = m_audioFile->getBitsPerSample() / 8;

    m_format = bytes;
    if (bytes == 3 || bytes == 4) // 24-bit PCM or 32-bit float
        m_format = 2; // write 16-bit PCM instead

    // for the progress dialog
    unsigned int apprxTotalBytes = m_audioFile->getSize();
    unsigned int byteCount = 0;

    for (int i = 0; i < channels; i++)
        channelPeaks.push_back(std::pair<int, int>());

    // clear down info
    m_numberOfPeaks = 0;
    m_bodyBytes = 0;
    m_positionPeakOfPeaks = 0;

    while (m_keepProcessing) {
        try {
            samples = m_audioFile->
                      getBytes(m_blockSize * channels * bytes);
        } catch (BadSoundFileException e) {
            std::cerr << "PeakFile::writePeaks: " << e.getMessage()
            << std::endl;
            break;
        }

        // If no bytes or less than the total number of bytes are returned
        // then break out
        //
        if (samples.length() == 0 ||
                samples.length() < (m_blockSize * m_audioFile->getChannels()
                                    * bytes))
            break;

        byteCount += samples.length();

        emit setProgress((int)(double(byteCount) /
                               double(apprxTotalBytes) * 100.0));
        kapp->processEvents();

        samplePtr = (unsigned char *)samples.c_str();

        for (int i = 0; i < m_blockSize; i++) {
            for (unsigned int ch = 0; ch < m_audioFile->getChannels(); ch++) {
                // Single byte format values range from 0-255 and then
                // shifted down about the x-axis.  Double byte and above
                // are already centred about x-axis.
                //
                if (bytes == 1) {
                    // get value
                    sampleValue = int(*samplePtr) - 128;
                    samplePtr++;
                } else if (bytes == 2) {
                    unsigned char b2 = samplePtr[0];
                    unsigned char b1 = samplePtr[1];
                    unsigned int bits = (b1 << 8) + b2;
                    sampleValue = (short)bits;
                    samplePtr += 2;
                } else if (bytes == 3) {
                    unsigned char b3 = samplePtr[0];
                    unsigned char b2 = samplePtr[1];
                    unsigned char b1 = samplePtr[2];
                    unsigned int bits = (b1 << 24) + (b2 << 16) + (b3 << 8);

                    // write out as 16-bit (m_format == 2)
                    sampleValue = int(bits) / 65536;

                    samplePtr += 3;
                } else if (bytes == 4)  // IEEE float (enforced by RIFFAudioFile)
                {
                    // write out as 16-bit (m_format == 2)
                    float val = *(float *)samplePtr;
                    sampleValue = (int)(32767.0 * val);
                    samplePtr += 4;
                } else {
                    throw(BadSoundFileException(m_fileName, "PeakFile::writePeaks - unsupported bit depth"));
                }

                // First time for each channel
                //
                if (i == 0) {
                    channelPeaks[ch].first = sampleValue;
                    channelPeaks[ch].second = sampleValue;
                } else {
                    // Compare and store
                    //
                    if (sampleValue > channelPeaks[ch].first)
                        channelPeaks[ch].first = sampleValue;

                    if (sampleValue < channelPeaks[ch].second)
                        channelPeaks[ch].second = sampleValue;
                }

                // Store peak of peaks if it fits
                //
                if (abs(sampleValue) > sampleMax) {
                    sampleMax = abs(sampleValue);
                    m_positionPeakOfPeaks = sampleFrameCount;
                }
            }

            // for peak of peaks as well as frame count
            sampleFrameCount++;
        }

        // Write absolute peak data in channel order
        //
        for (unsigned int i = 0; i < m_audioFile->getChannels(); i++) {
            putBytes(file, getLittleEndianFromInteger(channelPeaks[i].first,
                     m_format));
            putBytes(file, getLittleEndianFromInteger(channelPeaks[i].second,
                     m_format));
            m_bodyBytes += m_format * 2;
        }

        // increment number of peak frames
        m_numberOfPeaks++;
    }

#ifdef DEBUG_PEAKFILE
    cout << "PeakFile::writePeaks - "
    << "completed peaks" << endl;
#endif

}

// Get a normalised vector for the preview at a given horizontal resolution.
// We return a value for each channel and if returnLow is set we also return
// an interleaved low value for each channel.
//
//
std::vector<float>
PeakFile::getPreview(const RealTime &startTime,
                     const RealTime &endTime,
                     int width,
                     bool showMinima)
{
#ifdef DEBUG_PEAKFILE_BRIEF
    std::cout << "PeakFile::getPreview - "
    << "startTime = " << startTime
    << ", endTime = " << endTime
    << ", width = " << width
    << ", showMinima = " << showMinima << std::endl;
#endif

    if (getSize() == 0) {
        std::cout << "PeakFile::getPreview - PeakFile size == 0" << std::endl;
        return std::vector<float>();
    }

    // Regenerate cache on these conditions
    //
    if (!m_peakCache.length()) {
#ifdef DEBUG_PEAKFILE_CACHE
        std::cerr << "PeakFile::getPreview - no peak cache" << std::endl;
#endif

        if (getSize() < (256 *1024)) // if less than 256K PeakFile
        {
            // Scan to start of peak data
            scanToPeak(0);
            try
            {
                m_peakCache = getBytes(m_inFile, getSize() - 128);
            } catch (BadSoundFileException e)
            {
                std::cerr << "PeakFile::getPreview: " << e.getMessage()
                << std::endl;
            }

#ifdef DEBUG_PEAKFILE_CACHE
            std::cout << "PeakFile::getPreview - generated peak cache - "
            << "size = " << m_peakCache.length() << std::endl;
#endif

        } else {
#ifdef DEBUG_PEAKFILE_CACHE
            std::cout << "PeakFile::getPreview - file size = " << getSize()
            << ", not generating cache" << std::endl;
#endif

        }
    }

    // Check to see if we hit the "lastPreview" cache by comparing the last
    // query parameters we used.
    //
    if (startTime == m_lastPreviewStartTime && endTime == m_lastPreviewEndTime
            && width == m_lastPreviewWidth && showMinima == m_lastPreviewShowMinima) {
#ifdef DEBUG_PEAKFILE_CACHE
        std::cout << "PeakFile::getPreview - hit last preview cache" << std::endl;
#endif

        return m_lastPreviewCache;
    } else {
#ifdef DEBUG_PEAKFILE_CACHE
        std::cout << "PeakFile::getPreview - last preview " << m_lastPreviewStartTime
        << " -> " << m_lastPreviewEndTime << ", w " << m_lastPreviewWidth << "; this " << startTime << " -> " << endTime << ", w " << width << std::endl;
#endif

    }

    // Clear the cache - we need to regenerate it
    //
    m_lastPreviewCache.clear();

    int startPeak = getPeak(startTime);
    int endPeak = getPeak(endTime);

    // Sanity check
    if (startPeak > endPeak)
        return m_lastPreviewCache;

    // Actual possible sample length in RealTime
    //
    double step = double(endPeak - startPeak) / double(width);
    std::string peakData;
    int peakNumber;

#ifdef DEBUG_PEAKFILE_BRIEF

    std::cout << "PeakFile::getPreview - getting preview for \""
    << m_audioFile->getFilename() << "\"" << endl;
#endif

    // Get a divisor
    //
    float divisor = 0.0f;
    switch (m_format) {
    case 1:
        divisor = SAMPLE_MAX_8BIT;
        break;

    case 2:
        divisor = SAMPLE_MAX_16BIT;
        break;

    default:
#ifdef DEBUG_PEAKFILE_BRIEF

        std::cout << "PeakFile::getPreview - "
        << "unsupported peak length format (" << m_format << ")"
        << endl;
#endif

        return m_lastPreviewCache;
    }

    float *hiValues = new float[m_channels];
    float *loValues = new float[m_channels];

    for (int i = 0; i < width; i++) {

        peakNumber = startPeak + int(double(i) * step);
        int nextPeakNumber = startPeak + int(double(i + 1) * step);

        // Seek to value
        //
        if (!m_peakCache.length()) {

            if (scanToPeak(peakNumber) == false) {
#ifdef DEBUG_PEAKFILE
                std::cout << "PeakFile::getPreview: scanToPeak(" << peakNumber << ") failed" << std::endl;
#endif

                m_lastPreviewCache.push_back(0.0f);
            }
        }
#ifdef DEBUG_PEAKFILE
        std::cout << "PeakFile::getPreview: step is " << step << ", format * pointsPerValue * chans is " << (m_format * m_pointsPerValue * m_channels) << std::endl;
        std::cout << "i = " << i << ", peakNumber = " << peakNumber << ", nextPeakNumber = " << nextPeakNumber << std::endl;
#endif

        for (int ch = 0; ch < m_channels; ch++) {
            hiValues[ch] = 0.0f;
            loValues[ch] = 0.0f;
        }

        // Get peak value over channels
        //
        for (int k = 0; peakNumber < nextPeakNumber; ++k) {

            for (int ch = 0; ch < m_channels; ch++) {

                if (!m_peakCache.length()) {

                    try {
                        peakData = getBytes(m_inFile, m_format * m_pointsPerValue);
                    } catch (BadSoundFileException e) {
                        // Problem with the get - probably an EOF
                        // return the results so far.
                        //
#ifdef DEBUG_PEAKFILE
                        std::cout << "PeakFile::getPreview - \"" << e.getMessage() << "\"\n"
                        << endl;
#endif

                        goto done;
                    }
#ifdef DEBUG_PEAKFILE
                    std::cout << "PeakFile::getPreview - "
                    << "read from file" << std::endl;
#endif

                } else {

                    int valueNum = peakNumber * m_channels + ch;
                    int charNum = valueNum * m_format * m_pointsPerValue;
                    int charLength = m_format * m_pointsPerValue;

                    // Get peak value from the cached string if
                    // the value is valid.
                    //
                    if (charNum + charLength <= m_peakCache.length()) {
                        peakData = m_peakCache.substr(charNum, charLength);
#ifdef DEBUG_PEAKFILE

                        std::cout << "PeakFile::getPreview - "
                        << "hit peakCache" << std::endl;
#endif

                    }
                }


                if (peakData.length() != (unsigned int)(m_format *
                                                        m_pointsPerValue)) {
                    // We didn't get the whole peak block - return what
                    // we've got so far
                    //
#ifdef DEBUG_PEAKFILE
                    std::cout << "PeakFile::getPreview - "
                    << "failed to get complete peak block"
                    << endl;
#endif

                    goto done;
                }

                int intDivisor = int(divisor);
                int inValue =
                    getIntegerFromLittleEndian(peakData.substr(0, m_format));

                while (inValue > intDivisor) {
                    inValue -= (1 << (m_format * 8));
                }

#ifdef DEBUG_PEAKFILE
                std::cout << "found potential hivalue " << inValue << std::endl;
#endif

                if (k == 0 || inValue > hiValues[ch]) {
                    hiValues[ch] = float(inValue);
                }

                if (m_pointsPerValue == 2) {

                    inValue =
                        getIntegerFromLittleEndian(
                            peakData.substr(m_format, m_format));

                    while (inValue > intDivisor) {
                        inValue -= (1 << (m_format * 8));
                    }

                    if (k == 0 || inValue < loValues[ch]) {
                        loValues[ch] = inValue;
                    }
                }
            }

            ++peakNumber;
        }

        for (int ch = 0; ch < m_channels; ++ch) {

            float value = hiValues[ch] / divisor;

#ifdef DEBUG_PEAKFILE_BRIEF

            std::cout << "VALUE = " << hiValues[ch] / divisor << std::endl;
#endif

            if (showMinima) {
                m_lastPreviewCache.push_back(loValues[ch] / divisor);
            } else {
                value = fabs(value);
                if (m_pointsPerValue == 2) {
                    value = std::max(value, fabsf(loValues[ch] / divisor));
                }
                m_lastPreviewCache.push_back(value);
            }
        }
    }

done:
    resetStream();
    delete[] hiValues;
    delete[] loValues;

    // We have a good preview in the cache so store our parameters
    //
    m_lastPreviewStartTime = startTime;
    m_lastPreviewEndTime = endTime;
    m_lastPreviewWidth = width;
    m_lastPreviewShowMinima = showMinima;

#ifdef DEBUG_PEAKFILE_BRIEF

    std::cout << "Returning " << m_lastPreviewCache.size() << " items" << std::endl;
#endif

    return m_lastPreviewCache;
}

int
PeakFile::getPeak(const RealTime &time)
{
    double frames = ((time.sec * 1000000.0) + time.usec()) *
                    m_audioFile->getSampleRate() / 1000000.0;
    return int(frames / double(m_blockSize));
}

RealTime
PeakFile::getTime(int peak)
{
    int usecs = int((double)peak * (double)m_blockSize *
                    double(1000000.0) / double(m_audioFile->getSampleRate()));
    return RealTime(usecs / 1000000, (usecs % 1000000) * 1000);
}

// Get pairs of split points for areas that exceed a percentage
// threshold
//
std::vector<SplitPointPair>
PeakFile::getSplitPoints(const RealTime &startTime,
                         const RealTime &endTime,
                         int threshold,
                         const RealTime &minLength)
{
    std::vector<SplitPointPair> points;
    std::string peakData;

    int startPeak = getPeak(startTime);
    int endPeak = getPeak(endTime);

    if (endPeak < startPeak)
        return std::vector<SplitPointPair>();

    scanToPeak(startPeak);

    float divisor = 0.0f;
    switch (m_format) {
    case 1:
        divisor = SAMPLE_MAX_8BIT;
        break;

    case 2:
        divisor = SAMPLE_MAX_16BIT;
        break;

    default:
        return points;
    }

    float value;
    float fThreshold = float(threshold) / 100.0;
    bool belowThreshold = true;
    RealTime startSplit = RealTime::zeroTime;
    bool inSplit = false;

    for (int i = startPeak; i < endPeak; i++) {
        value = 0.0;

        for (int ch = 0; ch < m_channels; ch++) {
            try {
                peakData = getBytes(m_inFile, m_format * m_pointsPerValue);
            } catch (BadSoundFileException e) {
                std::cerr << "PeakFile::getSplitPoints: "
                << e.getMessage() << std::endl;
                break;
            }

            if (peakData.length() == (unsigned int)(m_format *
                                                    m_pointsPerValue)) {
                int peakValue =
                    getIntegerFromLittleEndian(peakData.substr(0, m_format));

                value += fabs(float(peakValue) / divisor);
            }
        }

        value /= float(m_channels);

        if (belowThreshold) {
            if (value > fThreshold) {
                startSplit = getTime(i);
                inSplit = true;
                belowThreshold = false;
            }
        } else {
            if (value < fThreshold && getTime(i) - startSplit > minLength) {
                // insert values
                if (inSplit) {
                    points.push_back(SplitPointPair(startSplit, getTime(i)));
                }
                inSplit = false;
                belowThreshold = true;
            }
        }
    }

    // if we've got a split point open the close it
    if (inSplit) {
        points.push_back(SplitPointPair(startSplit,
                                        getTime(endPeak)));
    }

    return points;
}


}


#include "PeakFile.moc"