I develop an application which the user can play multiple sounds at the same time. For this I use QMediaPlayer in conjunction with a matrix to hold each sound separately. The code is simple, for each sound I use a code like this:
media = new QMediaPlayer();
media->setMedia(QUrl::fromLocalFile(QFileInfo("sound.mp3").absoluteFilePath()));
media->play();
Everything is ok. But around playing the sound 115-125 (simultaneous sounds), the new sounds emit signal error(QMediaPlayer::ResourceError) with error code: QMediaPlayer::ResourceError - A media resource couldn't be resolved. Before emit error signal, it print on output this message: DirectShowPlayerService::doPlay: Unresolved error code 0x80004005 ()
This is not a problem, because I delete those sounds as soon as I detect this error.
The problem appears right after a couple of QMediaPlayer::ResourceError.
If I create a new sound, an error message appear on output window: QThread::start: Failed to create thread.
This error appear just after creating a new QMediaPlayer instance:
qDebug() << "before media = new QMediaPlayer(); (FILE)";
media = new QMediaPlayer();
qDebug() << "after media = new QMediaPlayer(); (FILE)" << media->error
The output:
before media = new QMediaPlayer(); (FILE)
QThread::start: Failed to create thread
after media = new QMediaPlayer(); (FILE) QMediaPlayer::NoError
This last kind of QMediaPlayer instance emit no error. More than that, the state is QMediaPlayer::PlayingState. But if I try to delete it delete(media) or to set the media to a null QMediaContent media->setMedia(QMediaContent()) to make the player to discard all information relating to the current media source, the application freezes.
Those two opperations works fine on he others sounds.
If I don't delete this kind of QMediaPlayer, I end to have no room for sounds. Somehow QMediaPlayer has a limited number of instances and every QMediaPlayer that I cannot delete anymore fill this number and let no room for new instances of QMediaPlayer.
The question is: how I can avoid this issue? If I limit the number of simultaneous sounds, what is the correct number of QMediaPlayer instances? If I set a limit, this limit can be to high for other machines. Or how to properly detect this malformed QMediaPlayer and properly delete it?
Also, if I wait for first QMediaPlayer::ResourceError signal to limit the number of sounds, this is sometimes too late, because the error signal is emitted a bit later and sometimes the application already create a malformed QMediaPlayer that I cannot delete anymore and this prevent the process to close.
Related
I want to play background music continually in a loop until the game ends.
in the header file:
QMediaPlayer * music = new QMediaPlayer();
in the cpp file:
startGame(){
music->setMedia(QUrl("qrc:/sounds/backgroundmusic.mp3"));
music->play(); }
stopGame(){
music->stop(); }
Right now my music plays thru to the end but does not restart. How can I get it to loop over again again?
Is there a QMediaPlayer member I can use, or should I run it in a while loop, or what?
Sounds like what you want is QMediaPlaylist. QMediaPlaylist allows you to control the playback mode, and in this case you would use Loop. This approach has other advantages too, such as CurrentItemInLoop. CurrentItemInLoop will play the current playlist item in a loop, meaning that if you add more songs in the future you can select a song then loop only that track. Thus, you only need a single playlist for most needs. Below is some example code, I do not currently have a means to test it though (No Qt multimedia extensions installed on this machine). Should demonstrate the point reasonably well though.
QMediaPlaylist *playlist = new QMediaPlaylist();
playlist->addMedia(QUrl("qrc:/sounds/backgroundmusic.mp3"));
playlist->setPlaybackMode(QMediaPlaylist::Loop);
QMediaPlayer *music = new QMediaPlayer();
music->setPlaylist(playlist);
music->play();
Hello Techie's I am working on Qt QMediaPlayer and trying to play song through my local file but i don't know where I am getting wrong I am unable to play song on Window but the same code is working fine in Mac but not on window.
For all kind helps Thanks in advance.
I had tried this
player->setMedia(QUrl::fromLocalFile("<path to file>/test.mp3"));
and this as well
player->setMedia(QMediaContent(QUrl::fromLocalFile("<path to file>/test.mp3")));
Here's my complete code snippet:
QMediaPlayer *player = new QMediaPlayer();
player->setMedia(QUrl::fromLocalFile("<path to file>/test.mp3"));
player->setVolume(100);
player->play();
qDebug() << player->errorString();
No error listed, so its difficult to identify where I am getting wrong.
Have you try some path format, i had a similar experience with QMediaPlayer and i had to use path format like this some\\path\\exemple.mp3 or like this some//path//exemple.mp3 i don't remember exactly.
Maybe check QMediaPlayer exemple and try to run the exemple to check if is codec problem or a code problem.
I'm connecting the QMediaPlayer::error() signal and trying to play a video file:
QMediaPlayer *player = new QMediaPlayer;
QMediaPlaylist *playlist = new QMediaPlaylist(player);
playlist->addMedia(QUrl::fromLocalFile("/path/to/file.mp4"));
QVideoWidget *videoWidget = new QVideoWidget;
player->setVideoOutput(videoWidget);
videoWidget->resize(640, 340);
videoWidget->show();
ErrorPrinter *errorPrinter = new ErrorPrinter(player);
QObject::connect(player, SIGNAL(error(QMediaPlayer::Error)), errorPrinter, SLOT(printError(QMediaPlayer::Error)));
player->play();
The video widget shows, but nothing is playing, so it must have failed somewhere. However, the QMediaPlayer::error() signal is never emitted! The Application Output is empty, there are no asserts, the play() function is void (no return value to indicate success or failure), and playlist->addMedia always returns true.
How am I supposed to find out what went wrong?
The QMediaPlaylist(player) construction only sets a QObject parent. It doesn't link the playlist to player - the player is unaware of the playlist.
So, you've never set the playlist on the player. You may also need to set the playlist index - to 1 or perhaps zero (? - the docs are not clear on that).
playlist->setCurrentIndex(1);
player->setPlayList(playlist);
player->play();
I'm using the QT Creator on Ubuntu.
I have GUI with a mainwindow and another window called "progress".
Upon clicking a button the QProcess starts and executes an rsync command which copies a folder into a specific directory. I created a textbrowser which reads the output from the rsync command. Also clicking the button causes the "progress" window to pop up.
So far so so good, now my problem.
Instead of showing the rsync output in my mainwindow i want it to be in progress.
I've tried several methods to get the QProcess into the progress via connect but that doesn't seem to work.
mainwindow.cpp
void MainWindow::on_pushButton_clicked()
{
if (ui->checkBox->isChecked()
)
m_time ="-t";
QObject parent;
m_myProcess = new QProcess();
connect(m_myProcess, SIGNAL(readyReadStandardOutput()),this, SLOT(printOutput()));
QString program = "/usr/bin/rsync";
arguments << "-r" << m_time << "-v" <<"--progress" <<"-s"
<< m_dir
<< m_dir2;
m_myProcess->start(program, arguments);
}
progress.cpp
void Progress::printOutput()
{
ui->textBrowser->setPlainText(m_myProcess->readAllStandardOutput());
}
I know it's pretty messy iv'e tried alot of things and haven't cleaned the code yet also I'm pretty new to c++.
My goal was to send the QProcess (m_myProcess) to progress via connect but that didn't seem to work.
Can you send commands like readyReadAllStandardOutput via connect to other windows (I don't know the right term )?
Am I doing a mistake or is there just another way to get the output to my progress window ?
m_myProcess is a member of the class MainWindow and you haven't made it visible to the class Progress. That's why you have the compilation error
m_myProcess was not declared in this scope
What you could do:
Redirect standard error of m_myProcess to standard output, such that you also print what is sent to standard error (unless you want to do something else with it). Using
m_myProcess.setProcessChannelMode(QProcess::MergedChannels);
Make the process object available outside MainWindow
QProcess* MainWindow::getProcess()
{
return m_myProcess;
}
Read the process output line by line in Progress. It needs to be saved in a buffer because readAllStandardOutput() only return the data which has been written since the last read.
... // somewhere
connect(window->getProcess(), SIGNAL(readyReadStandardOutput()), this, SLOT(printOutput())
...
void Progress::printOutput(){
//bigbuffer is member
bigbuffer.append(myProcess->readAllStandardOutput();)
ui->textBrowser->setPlainText(bigbuffer);
}
I try to play mp3 files declared in the resource, but it show:
Btn clicked
current media: "qrc://sound/sound/FarAway.mp3"
Error : QMediaPlayer::FormatError
Media state : QMediaPlayer::InvalidMedia
Here's how I set media:
player = new QMediaPlayer(this);
player->setMedia(QUrl(mediaFilePath));
qDebug() << "current media: " << player->currentMedia().canonicalUrl().toString();
connect(player, SIGNAL(stateChanged(QMediaPlayer::State)), SLOT(handleStateChanged(QMediaPlayer::State)));
connect(player, SIGNAL(mediaStatusChanged(QMediaPlayer::MediaStatus)), SLOT(handleMediaStateChanged(QMediaPlayer::MediaStatus)));
connect(player, SIGNAL(error(QMediaPlayer::Error)), SLOT(handleError(QMediaPlayer::Error)));
According to this post it said QMediaPlayer need to be called play() after the callback of mediaStatusChanged(), which is what I've done exactly. So what's the problem???
P.S. I could play the mp3 file from the QMediaPlayer Example as local file.
UPDATE 1: I can play the mp3 file as local file...
Your problem is now no longer a problem, you can play a Qt resource in the QMediaPlayer. Answer found here, and I'm confirming it here in case people are looking.
This code works for me when testing in my local project.
player->setMedia(QUrl("qrc:/audio/audio/Revival_Song01.mp3"));
You should play a file from disk; not a Qt resource. Since the resources are not supported yet. You can copy the file from resource to your hard drive on the fly and then play it :
QFile::copy(":/files/FarAway.mp3" , "/some/path/FarAway.mp3");