Playing wav file with portaudio and sndfile

Question

I have written a function to play a sound file using portaudio and sndfile. Unfortunately the sound quality is terrible. The sound is more like a hiss. The following is the source code of the function I am using.

#define _GLIBCXX_USE_C99_MATH 1
#include "PlaySound_config.h"
#include <boost/predef.h>

#if !defined(USE_PORTAUDIO) // {
#  define USE_PORTAUDIO 0
#  if (! BOOST_OS_CYGWIN && ! BOOST_OS_WINDOWS) // {
#    undef USE_PORTAUDIO
#    define USE_PORTAUDIO 1
#  endif // }
#endif // }

#if (PLAY_SOUND_HAVE_PORTAUDIO_H && PLAY_SOUND_HAVE_SNDFILE_H && PLAY_SOUND_HAVE_SNDFILE_HH && USE_PORTAUDIO) // {

#if (PLAY_SOUND_HAVE_UNISTD_H)
#  include <unistd.h>
#endif

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>

#include <portaudio.h>
#include <sndfile.hh>

#include <cmath>
#include <fstream>
#include <iostream>
#include <vector>

#include <boost/filesystem/operations.hpp>
#include <boost/filesystem/path.hpp>
#include <boost/format.hpp>

#include "PlaySound.h"
#include "PlaySoundStrings.h"

void SoundWarning(const std::string& message)
{
    std::cerr << message << std::endl;
}

bool PlaySoundFile(const std::string& soundFile, unsigned long /* volume */)
{
    const int MAX_CHANNELS = 1;
    const double SAMPLE_RATE = 11025.0;
    const unsigned long FRAMES_PER_BUFFER = 1024;
    const size_t BUFFER_LEN = 1024;
    using boost::format;
    using boost::io::group;
    std::string message;
    if (soundFile.empty())
    {
        errno = EINVAL;
        message = playSoundStrings[error_invalid_argument];
        SoundWarning(message);
        return false;
    }
    boost::filesystem::path soundFilePath(soundFile);
    if (! boost::filesystem::exists(soundFilePath))
    {
        errno = EINVAL;
        message = str(format(playSoundStrings[error_file_does_not_exist]) % soundFile.c_str());
        SoundWarning(message);
        return false;
    }
    PaError paError = Pa_Initialize();
    if (paError != paNoError)
    {
        message = str(format(playSoundStrings[error_pa_initialize_failed]) % Pa_GetErrorText(paError));
        SoundWarning(message);
        return false;
    }
    SNDFILE* sndFile;
    SF_INFO sfInfo;
    sndFile = sf_open(soundFile.c_str(), SFM_READ, &sfInfo);
    if (! sndFile)
    {
        message = str(format(playSoundStrings[error_sf_open_failed]) % soundFile.c_str() % sf_strerror(nullptr));
        SoundWarning(message);
        Pa_Terminate();
        return false;
    }
    if (sfInfo.channels > MAX_CHANNELS)
    {
        message = str(format(playSoundStrings[error_too_many_channels]) % sfInfo.channels % MAX_CHANNELS);
        SoundWarning(message);
        Pa_Terminate();
        return false;
    }
    PaStream* stream = nullptr;
    PaStreamParameters paStreamParameters;
    paStreamParameters.device = Pa_GetDefaultOutputDevice();
    paStreamParameters.channelCount = sfInfo.channels;
    paStreamParameters.sampleFormat = paInt16;
    paStreamParameters.suggestedLatency = Pa_GetDeviceInfo(paStreamParameters.device)->defaultLowOutputLatency;
    paStreamParameters.hostApiSpecificStreamInfo = nullptr;
    paError = Pa_OpenStream(
        &stream, nullptr, &paStreamParameters,
        SAMPLE_RATE, FRAMES_PER_BUFFER, paClipOff,
        nullptr, nullptr);
    if (paError != paNoError || ! stream)
    {
        message = str(format(playSoundStrings[error_pa_open_stream_failed]) % Pa_GetErrorText(paError));
        SoundWarning(message);
        Pa_Terminate();
        return false;
    }
    paError = Pa_StartStream(stream);
    if (paError != paNoError)
    {
        message = str(format(playSoundStrings[error_pa_start_stream_failed]) % Pa_GetErrorText(paError));
        SoundWarning(message);
        Pa_Terminate();
        return false;
    }
    sf_count_t readCount = 0;
    double data[BUFFER_LEN];
    while ((readCount = sf_read_double(sndFile, data, BUFFER_LEN)))
    {
        paError = Pa_WriteStream(stream, data, BUFFER_LEN);
        if (paError != paNoError)
        {
            message = str(format(playSoundStrings[error_pa_write_stream_failed]) % Pa_GetErrorText(paError));
            SoundWarning(message);
            break;
        }
    }
    paError = Pa_CloseStream(stream);
    if (paError != paNoError)
    {
        message = str(format(playSoundStrings[error_pa_close_stream_failed]) % Pa_GetErrorText(paError));
        SoundWarning(message);
        Pa_Terminate();
        return false;
    }
    Pa_Terminate();
    return true;
}

I saw some sample code in the article What is a lightweight cross platform WAV playing library? but the sample is incomplete. It appears that it will only play the first five seconds of the file. I want to play the entire file.

Any idea what I am doing wrong?

This code is part of my PlaySound project.

Answer 1

I made several mistakes in the original version of my code. The first was in the line in which I initialized the sampleFormat member of the PaStreamParameters structure.

In my original code I initialized this member as follows.

paStreamParameters.sampleFormat = paInt16;

I should have initialized it as follows.

paStreamParameters.sampleFormat = paInt32;

My next mistake was in the call to the Pa_OpenStream function. I set the sampleRate parameter to a hard coded constant, in this case 11025.0. I should have set it to the value of the samplerate member of the SF_INFO structure.

My third mistake was to use the sf_read_double function to read from the sound file. In several working samples I eventually found, including the sndfile-play application, the sf_read_float function is used instead.

My forth mistake is that I did not scale the data read from the sound file before passing it to the Pa_WriteStream function. I found the code to scale the data in the source code of the sndfile-play application.

For anyone who is interested, the final version of my source code is as follows.

#define _GLIBCXX_USE_C99_MATH 1
#include "PlaySound_config.h"
#include <boost/predef.h>

#if !defined(USE_PORTAUDIO) // {
#  define USE_PORTAUDIO 0
#  if (! BOOST_OS_CYGWIN && ! BOOST_OS_WINDOWS) // {
#    undef USE_PORTAUDIO
#    define USE_PORTAUDIO 1
#  endif // }
#endif // }

#if (PLAY_SOUND_HAVE_PORTAUDIO_H && PLAY_SOUND_HAVE_SNDFILE_H && PLAY_SOUND_HAVE_SNDFILE_HH && USE_PORTAUDIO) // {

#if (PLAY_SOUND_HAVE_UNISTD_H)
#  include <unistd.h>
#endif

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <portaudio.h>
#include <sndfile.hh>

#include <cmath>
#include <fstream>
#include <iostream>
#include <vector>

#include <boost/filesystem/operations.hpp>
#include <boost/filesystem/path.hpp>
#include <boost/format.hpp>

#include "PlaySound.h"
#include "PlaySoundStrings.h"

void SoundWarning(const std::string& message)
{
    std::cerr << message << std::endl;
}

bool PlaySoundFile(const std::string& soundFile, unsigned long /* volume */)
{
    const int MAX_CHANNELS = 1;
    const size_t BUFFER_LEN = 1024;
    using boost::format;
    using boost::io::group;
    std::string message;
    if (soundFile.empty())
    {
        errno = EINVAL;
        message = playSoundStrings[error_invalid_argument];
        SoundWarning(message);
        return false;
    }
    boost::filesystem::path soundFilePath(soundFile);
    if (! boost::filesystem::exists(soundFilePath))
    {
        errno = EINVAL;
        message = str(format(playSoundStrings[error_file_does_not_exist]) % soundFile.c_str());
        SoundWarning(message);
        return false;
    }
    PaError paError = Pa_Initialize();
    if (paError != paNoError)
    {
        message = str(format(playSoundStrings[error_pa_initialize_failed]) % Pa_GetErrorText(paError));
        SoundWarning(message);
        return false;
    }
    SNDFILE* sndFile = nullptr;
    SF_INFO sfInfo;
    ::memset(&sfInfo, 0, sizeof(sfInfo));
    sndFile = sf_open(soundFile.c_str(), SFM_READ, &sfInfo);
    if (! sndFile)
    {
        message = str(format(playSoundStrings[error_sf_open_failed]) % soundFile.c_str() % sf_strerror(nullptr));
        SoundWarning(message);
           Pa_Terminate();
        return false;
    }
    if (sfInfo.channels > MAX_CHANNELS)
    {
        message = str(format(playSoundStrings[error_too_many_channels]) % sfInfo.channels % MAX_CHANNELS);
        SoundWarning(message);
        Pa_Terminate();
        return false;
    }
    PaStream* stream = nullptr;
    PaStreamParameters paStreamParameters;
    paStreamParameters.device = Pa_GetDefaultOutputDevice();
    paStreamParameters.channelCount = sfInfo.channels;
    paStreamParameters.sampleFormat = paInt32;
    paStreamParameters.suggestedLatency = Pa_GetDeviceInfo(paStreamParameters.device)->defaultLowOutputLatency;
    paStreamParameters.hostApiSpecificStreamInfo = nullptr;
    paError = Pa_OpenStream(
        &stream, nullptr, &paStreamParameters,
        sfInfo.samplerate, paFramesPerBufferUnspecified, paClipOff,
        nullptr, nullptr);
    if (paError != paNoError || ! stream)
    {
        message = str(format(playSoundStrings[error_pa_open_stream_failed]) % Pa_GetErrorText(paError));
        SoundWarning(message);
        Pa_Terminate();
        return false;
    }
    paError = Pa_StartStream(stream);
    if (paError != paNoError)
    {
        message = str(format(playSoundStrings[error_pa_start_stream_failed]) % Pa_GetErrorText(paError));
        SoundWarning(message);
        Pa_Terminate();
        return false;
    }
    int subFormat = sfInfo.format & SF_FORMAT_SUBMASK;
    double scale = 1.0;
    if (subFormat == SF_FORMAT_FLOAT || subFormat == SF_FORMAT_DOUBLE)
    {
        sf_command(sndFile, SFC_CALC_SIGNAL_MAX, &scale, sizeof(scale));
        if (scale < 1e-10)
        {
            scale = 1.0;
        }
        else
        {
            scale = 32700.0 / scale;
        }
    }
    sf_count_t readCount = 0;
    float data[BUFFER_LEN];
    ::memset(data, 0, sizeof(data));
    while ((readCount = sf_read_float(sndFile, data, BUFFER_LEN)))
    {
        if (subFormat == SF_FORMAT_FLOAT || subFormat == SF_FORMAT_DOUBLE)
        {
            int m = 0;
            for (m = 0 ; m < readCount ; ++m)
            {
                data[m] *= scale;
            }
        }
        paError = Pa_WriteStream(stream, data, BUFFER_LEN);
        if (paError != paNoError)
        {
            message = str(format(playSoundStrings[error_pa_write_stream_failed]) % Pa_GetErrorText(paError));
            SoundWarning(message);
            break;
        }
        ::memset(data, 0, sizeof(data));
    }
    paError = Pa_CloseStream(stream);
    if (paError != paNoError)
    {
        message = str(format(playSoundStrings[error_pa_close_stream_failed]) % Pa_GetErrorText(paError));
        SoundWarning(message);
        Pa_Terminate();
        return false;
    }
    Pa_Terminate();
    return true;
}