15.1.219. tablet_qt/lib/soundfunc.cpp¶
/*
Copyright (C) 2012, University of Cambridge, Department of Psychiatry.
Created by Rudolf Cardinal (rnc1001@cam.ac.uk).
This file is part of CamCOPS.
CamCOPS 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 3 of the License, or
(at your option) any later version.
CamCOPS is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with CamCOPS. If not, see <https://www.gnu.org/licenses/>.
*/
#include "soundfunc.h"
#include <QAudioDevice>
#include <QAudioOutput>
#include <QDebug>
#include <QMediaDevices>
#include <QObject>
#include <QMediaPlayer>
#include "maths/mathfunc.h"
namespace soundfunc {
const QString UNABLE_TO_CREATE_MEDIA_PLAYER("Unable");
void makeMediaPlayer(QSharedPointer<QMediaPlayer>& player)
{
// qDebug() << "Default QMediaPlayer() flags: " << static_cast<int>(QMediaPlayer::Flags());
// default "flags" argument to QMediaPlayer() is 0, i.e. no flags set.
qDebug() << "About to call QMediaPlayer()...";
player = QSharedPointer<QMediaPlayer>(new QMediaPlayer(),
&QObject::deleteLater);
auto audio_output = new QAudioOutput();
audio_output->setDevice(QMediaDevices::defaultAudioOutput());
player->setAudioOutput(audio_output);
// https://doc.qt.io/qt-6.5/qsharedpointer.html
// Failing to use deleteLater() can cause crashes, as there may be
// outstanding events relating to this object.
// ... but it's not enough; see finishMediaPlayer().
qDebug() << "... QMediaPlayer() has returned.";
/*
Near-crash; very long pause 2019-09-06. Looks like it relates to GStreamer:
1 ?? 0x7ffff7bcefd7
2 ?? 0x7ffff7bcfba8
3 ?? 0x7ffff7bcfbda
4 g_type_add_interface_static 0x7ffff7bd10d6
5 gst_bin_get_type 0x7ffff6d009b0
6 ?? 0x7ffff6cf74fc
7 g_option_context_parse 0x7ffff13a58a8
8 gst_init_check 0x7ffff6cf84cf
9 gst_init 0x7ffff6cf8524
10 QGstreamerPlayerServicePlugin::create(QString const&) 0x555555f98cd2
11 QPluginServiceProvider::requestService(QByteArray const&, QMediaServiceProviderHint const&) 0x555556581e9e
12 QMediaPlayer::QMediaPlayer(QObject *, QFlags<QMediaPlayer::Flag>) 0x5555565aed69
13 soundfunc::makeMediaPlayer soundfunc.cpp 31 0x5555558a5214
14 CardinalExpectationDetection::startTask cardinalexpectationdetection.cpp 770 0x555555adbc7b
... <More>
or
1 sched_yield syscall-template.S 78 0x7ffff0613e57
2 ?? 0x7fffc78841b9
3 ?? 0x7fffc78708e0
4 ?? 0x7fffc75db94f
5 ?? 0x7fffc75d0f00
6 vaTerminate 0x7fffccb2f542
7 ?? 0x7fffcd7ec3ad
8 g_object_unref 0x7ffff6a8a012
9 gst_object_replace 0x7ffff6cf9a10
10 ?? 0x7fffcd7c17a3
11 ?? 0x7fffcd7cc16b
12 ?? 0x7ffff7269f11
13 gst_element_change_state 0x7ffff6d26d5e
14 ?? 0x7ffff6d27499
15 QGstreamerVideoOverlay::QGstreamerVideoOverlay(QObject *, QByteArray const&) 0x555555faef15
16 QGstreamerVideoWidgetControl::QGstreamerVideoWidgetControl(QObject *, QByteArray const&) 0x555555fb9c55
17 QGstreamerPlayerService::QGstreamerPlayerService(QObject *) 0x555555f991c5
18 QGstreamerPlayerServicePlugin::create(QString const&) 0x555555f98d01
19 QPluginServiceProvider::requestService(QByteArray const&, QMediaServiceProviderHint const&) 0x55555658206e
20 QMediaPlayer::QMediaPlayer(QObject *, QFlags<QMediaPlayer::Flag>) 0x5555565aef39
21 soundfunc::makeMediaPlayer soundfunc.cpp 31 0x5555558a5199
22 CardinalExpectationDetection::startTask cardinalexpectationdetection.cpp 760 0x555555adb996
... <More>
This is potentially related to
https://github.com/OpenBoard-org/OpenBoard/issues/4. On shrike:
$ gst-inspect-1.0 --version
gst-inspect-1.0 version 1.14.5
GStreamer 1.14.5
https://launchpad.net/distros/ubuntu/+source/gstreamer1.0
*/
}
void finishMediaPlayer(const QSharedPointer<QMediaPlayer>& player)
{
// The following seems to prevent a crash (even with deleteLater set up by
// the QSharedPointer<QMediaPlayer>(new ...) call) whereby ongoing events
// try to go to a non-existing QMediaPlayer.
// Looks like this is not an uncommon problem:
// https://www.google.com/?ion=1&espv=2#q=delete%20qmediaplayer%20crash
// The crash comes from QMetaObject, from the Qt event loop.
if (player) {
player->stop();
}
}
void setVolume(const QSharedPointer<QMediaPlayer>& player,
const int volume_percent)
{
const qreal volume_proportion = mathfunc::intPercentToProportion(volume_percent);
setVolume(player, volume_proportion);
}
void setVolume(const QSharedPointer<QMediaPlayer>& player,
const double volume_proportion)
{
QAudioOutput* output = player->audioOutput();
if (output) {
output->setVolume(volume_proportion); // argument range: 0 to 1
}
}
} // namespace soundfunc