Piano fast in windows, slow in linux?

[Laurent]

Correct

[FPtje]

By the way, the same program on the windows installation on the same laptop is fast. so Linux is the problem.

[Nexus]

Here is a quick and dirty replacement:

Code: [Select]

...
std::vector<sf::Music*> Piano;
...

int main()
{
    Piano.resize(100, new sf::Music(10000));
    ...

    for (int i = 0; i < 100; ++i)
        delete Piano[i];

    return EXIT_SUCCESS;
}

Be careful, since std::vector::resize() only copies the pointer and not the value behind it. 99 of 100 delete-statements result in undefined behaviour.

[Laurent]

That's what we said previously

[Nexus]

Oh sorry, didn't see that... :oops:

[FPtje]

So does anyone know the cause of this problem?

[Laurent]

Have you tried using sf::Sound instead of sf::Music? sf::Music is really overkill for playing such a small sound, the audio samples are reloaded/streamed from the disk every time you play the music.

[FPtje]

Yes I have, someone helped me with it:

Code: [Select]

#include <SFML/Window.hpp>
#include <SFML/Audio.hpp>
#include <SFML/Graphics.hpp>
#include <iostream>

sf::Sound Piano[100];
sf::SoundBuffer PianoSound;

void PlayPiano(float pitch);
int width = sf::VideoMode::GetMode(0).Width;
int height = sf::VideoMode::GetMode(0).Height;

int main()
{
    PianoSound.LoadFromFile( "piano.wav");
    //I know I shouldnt be doing this, but I dont know of any other way, Im still learning
    for (int i = 0;i < 100; i++){
        Piano[i].SetBuffer(PianoSound);
    }

    // Create the main window
    sf::RenderWindow App(sf::VideoMode::GetMode(0), "Piano!", sf::Style::Fullscreen);
    // Piano picture
sf::Image pianopic;
pianopic.LoadFromFile("PianoPic.tga");


sf::Sprite PianoSprite;
PianoSprite.SetImage(pianopic);
    PianoSprite.SetPosition(0,0);
    PianoSprite.SetCenter(0, 0);
    PianoSprite.Resize(width, height);

App.Clear(sf::Color(0, 100, 0));
App.Draw(PianoSprite);
    App.Display();

    sf::Event PressKey;
    std::cout << "Start playing the piano!"<<std::endl << "Press escape to quit!" << std::endl;
    // Start main loopv
    bool running = true;
    while (running){
        while(App.GetEvent(PressKey)){
            if (PressKey.Type == sf::Event::KeyPressed) {

              //Toets ingedrukt
                switch(PressKey.Key.Code){
                    // insert cases here.
                    case (sf::Key::Escape):
                        App.Close();
                        running = false;
                        break;
                    default:
                        break;
                }
            }
        }
    }

    return EXIT_SUCCESS;
}

void PlayPiano(float pitch){
    for (int i = 0; i < 100; i++){
        if (Piano[i].GetStatus() != Piano[i].Playing){
             Piano[i].Stop();
             Piano[i].SetPitch (pitch);
             Piano[i].Play();
             break;
        }
    }
}


[Laurent]

And it made no difference at all?

[FPtje]

No difference at all.

[FPtje]

There seems to be a delay in this application too:

Code: [Select]


////////////////////////////////////////////////////////////
// Headers
////////////////////////////////////////////////////////////
#include <SFML/Audio.hpp>
#include <iomanip>
#include <iostream>


////////////////////////////////////////////////////////////
/// Entry point of application
///
/// \return Application exit code
///
////////////////////////////////////////////////////////////
int main()
{
    int a;
    std::cin >> a;
    std::cout << "TEST" << std::endl;
    // Load a sound buffer from a wav file
    sf::SoundBuffer Buffer;
    if (!Buffer.LoadFromFile("sound.wav"))
        return EXIT_FAILURE;

    // Display sound informations
    std::cout << "sound.wav :" << std::endl;
    std::cout << " " << Buffer.GetDuration()      << " sec"           << std::endl;
    std::cout << " " << Buffer.GetSampleRate()    << " samples / sec" << std::endl;
    std::cout << " " << Buffer.GetChannelsCount() << " channels"      << std::endl;

    // Create a sound instance and play it
    sf::Sound Sound(Buffer);
    Sound.Play();

    // Loop while the sound is playing
    while (Sound.GetStatus() == sf::Sound::Playing)
    {
        // Display the playing position
        std::cout << "\rPlaying... " << std::fixed << std::setprecision(2) << Sound.GetPlayingOffset() << " sec";

        // Leave some CPU time for other threads
        sf::Sleep(0.1f);
    }
    std::cout << std::endl;

    // Wait until the user presses 'enter' key
    std::cout << "Press enter to exit..." << std::endl;
    std::cin.ignore(10000, '\n');

    return EXIT_SUCCESS;
}


[Laurent]

In this case it could be the loading.

[FPtje]

no it isn't

[drmoth]

Hi,

I've recently been running the Linux version of the audio subsystem of SFML and it works fine. The latency with the latest version of OpenAL Soft is really very good under Alsa (I have a crappy integrated laptop sound card).

You can tweak the buffer size of the OpenAL Soft driver in a config file in order to improve latency. Download the OpenAL Soft source package and read the contents of the alsoft.conf file.

If you have really large latencies you are possibly running OpenAL under pulseaudio.

Latencies in audio occur under Linux when your audio is not set up properly. There's a good guide to lowering latencies of audio under Linux that comes with the demo of Pianoteq (http://www.pianoteq.com/)