Unable to read Qprocess output

Jaswinder

I am using qprocess to execute command line ffmpeg. when i pass "-help" commant to ffmpeg then this return me results otherwise this show me blank screen.
Here is my code.
@#include <QtCore/QCoreApplication>
#include <QProcess>
#include <QDebug>
#include <QTextStream>

int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);

QProcess *proc= new QProcess();
QString line;
QStringList argumenta= QStringList()<<"-i"<<" a.mp3";
proc->start("ffmpeg/ffmpeg",argumenta);
proc->waitForFinished();
qDebug()<<proc->readAllStandardOutput();
QTextStream *reader = new QTextStream(proc->readAllStandardOutput());
while((line=reader->readAll())!=NULL)
{
    //qDebug()<<line;
}

return a.exec&#40;&#41;;

}
@

luca.cossaro

Hi,

maybe ffmpeg prints on standard error?
@proc->readAllStandardError()@

andre

Might I recommend that you don't use the synchronous API (waitFor...), but use the async API (signals & slots) instead? Note that you can also combine both the output streams by using setProcessChannelMode(QProcess::MergedChannels).

Jaswinder

Hi ,
i created slots for this
@
QProcess *proc = new QProcess();
void ffmpeghandler::OnBtnStartClicked()
{
QObject parent;

QString codec = "ffmpeg/ffmpeg";
QStringList arguments;// = new List<string>();
arguments<<"-i";
arguments<<"abc.wmv";
arguments<<"-acodec";
arguments<<"mp3";
arguments<<"abc.mp3";
proc->execute(codec, arguments);

}

void ffmpeghandler::OnProcessOutputReady()
{
proc->waitForBytesWritten();
qDebug()<< "Transcoding Done."<< proc->readAllStandardOutput();
}@

This is working for the windows but not for the iMac OSX. I am using OSX build for MAC(ffmpeg) and for windows i am using (ffmpeg.exe).
Is there is any other way to to this.

This code is working for the MAC.
@proc->startDetached(codec, arguments);
proc->waitForFinished();
@