Allow choosing ffmpeg path in recording export

Useful on Windows where nothing is in your PATH and manipulating it
requires at least a BSc in computer science. The error about being
unable to start ffmpeg will now also tell you how to get it: download
from ffmpeg.org on Windows, install through Homebrew on macOS and use
your package manager on Linux.

This should also now handle errors when starting the exporter properly,
instead of getting stuck in some limbo state where you can't restart the
export. Instead, it will properly dispose of the exporter and re-show
the export dialog if starting the process failed.

ChangeLog

@@ -33,6 +33,7 @@ Unreleased Version 2.2.0-pre
  * Fix: Make Erase, Divide and Subtract layer modes in ORA files compatible with Krita.
  * Feature: Stick ID alias and listing hosting options behind an advanced options checkbox, since they keep causing confusion.
  * Fix: Make host page in the start dialog work properly on Arabic and other right-to-left languages.
+ * Feature: Allow choosing ffmpeg path on Windows. Thanks xxxx for suggesting.
 
 2023-08-26 Version 2.2.0-beta.7
  * Fix: Make classic brushes not go brighter when smudging into transparency. Thanks to cada for reporting.

src/desktop/dialogs/playbackdialog.cpp

@@ -303,50 +303,62 @@ void PlaybackDialog::keyPressEvent(QKeyEvent *event)
 #ifndef Q_OS_ANDROID
 void PlaybackDialog::onVideoExportClicked()
 {
-	QScopedPointer<VideoExportDialog> dialog(new VideoExportDialog(this));
-	VideoExporter *ve = nullptr;
-
-	// Loop until the user has selected a valid exporter
-	// configuration or cancelled.
-	while(!ve) {
-		if(dialog->exec() != QDialog::Accepted)
-			return;
-
-		ve = dialog->getExporter();
-	}
+	VideoExportDialog *dlg = new VideoExportDialog(this);
+	dlg->setAttribute(Qt::WA_DeleteOnClose);
+	dlg->setWindowModality(Qt::WindowModal);
+	connect(dlg, &QDialog::accepted, this, [this, dlg]() {
+		startVideoExport(dlg->getExporter());
+	});
+	dlg->show();
+}
 
-	m_exporter = ve;
+void PlaybackDialog::startVideoExport(VideoExporter *exporter)
+{
+	m_exporter = exporter;
 	m_exporter->setParent(this);
 	m_exporter->start();
 
 	m_ui->exportStack->setCurrentIndex(0);
 	m_ui->saveFrame->setEnabled(true);
-	connect(m_exporter, &VideoExporter::exporterFinished, this, [this]() {
-		setPlaying(false);
-		m_ui->exportStack->setCurrentIndex(1);
-	});
-	connect(
-		m_exporter, &VideoExporter::exporterFinished, m_exporter,
-		&VideoExporter::deleteLater);
 
+	connect(
+		m_exporter, &VideoExporter::exporterFinished, this,
+		&PlaybackDialog::videoExporterFinished);
 	connect(
 		m_exporter, &VideoExporter::exporterError, this,
-		[this](const QString &msg) {
-			setPlaying(false);
-			QMessageBox::warning(this, tr("Video error"), msg);
-		});
-
+		&PlaybackDialog::videoExporterError);
 	connect(
 		m_ui->saveFrame, &QAbstractButton::clicked, this,
 		&PlaybackDialog::exportFrame);
 	connect(
 		m_ui->stopExport, &QAbstractButton::clicked, m_exporter,
 		&VideoExporter::finish);
-
 	connect(
 		m_exporter, &VideoExporter::exporterReady, this,
 		&PlaybackDialog::onExporterReady);
 }
+
+void PlaybackDialog::videoExporterError(const QString &msg)
+{
+	setPlaying(false);
+	QMessageBox::warning(this, tr("Video error"), msg);
+}
+
+void PlaybackDialog::videoExporterFinished(bool showExportDialogAgain)
+{
+	setPlaying(false);
+	m_ui->exportStack->setCurrentIndex(1);
+
+	if(m_exporter) {
+		m_exporter->deleteLater();
+		m_exporter = nullptr;
+	}
+
+	if(showExportDialogAgain) {
+		QMetaObject::invokeMethod(
+			this, "onVideoExportClicked", Qt::QueuedConnection);
+	}
+}
 #endif
 
 void PlaybackDialog::exportFrame(int count)

src/desktop/dialogs/playbackdialog.h

@@ -56,6 +56,8 @@ private slots:
 	void onBuildIndexClicked();
 #ifndef Q_OS_ANDROID
 	void onVideoExportClicked();
+	void videoExporterError(const QString &msg);
+	void videoExporterFinished(bool showExportDialogAgain);
 #endif
 
 	void exportFrame(int count = 1);
@@ -65,6 +67,10 @@ private slots:
 	void updateButtons();
 	static bool isErrorResult(DP_PlayerResult result);
 
+#ifndef Q_OS_ANDROID
+	void startVideoExport(VideoExporter *exporter);
+#endif
+
 	Ui_PlaybackDialog *m_ui;
 	canvas::PaintEngine *m_paintengine;
 	QPointer<VideoExporter> m_exporter;

src/desktop/dialogs/videoexportdialog.cpp

@@ -67,10 +67,12 @@ VideoExportDialog::VideoExportDialog(QWidget *parent) :
 	settings.bindVideoExportFrameWidth(m_ui->framewidth);
 	settings.bindVideoExportFrameHeight(m_ui->frameheight);
 	settings.bindVideoExportSizeChoice(m_ui->sizeChoice, std::nullopt);
+	settings.bindVideoExportFfmpegPath(m_ui->ffmpegPathEdit);
+	settings.bindVideoExportFfmpegPath(this, &VideoExportDialog::updateUi);
 	settings.bindVideoExportCustomFfmpeg(m_ui->ffmpegCustom);
-
-	// Check for ffmpeg
-	m_ui->ffmpegNotFoundWarning->setHidden(FfmpegExporter::checkIsFfmpegAvailable());
+	connect(
+		m_ui->ffmpegPathButton, &QAbstractButton::clicked, this,
+		&VideoExportDialog::chooseFfmpegPath);
 
 	updateUi();
 }
@@ -80,6 +82,22 @@ VideoExportDialog::~VideoExportDialog()
 	delete m_ui;
 }
 
+void VideoExportDialog::chooseFfmpegPath()
+{
+#ifdef Q_OS_WINDOWS
+	QString executableFilter =
+		//: Used for picking a kind of file, used like "Executables (*.exe)".
+		QStringLiteral("%1 (*.exe)").arg(tr("Executables"));
+#else
+	QString executableFilter;
+#endif
+	QString ffmpegPath = QFileDialog::getOpenFileName(
+		this, tr("Choose ffmpeg path"), QString(), executableFilter);
+	if(!ffmpegPath.isEmpty()) {
+		m_ui->ffmpegPathEdit->setText(ffmpegPath);
+	}
+}
+
 void VideoExportDialog::updateUi()
 {
 	VideoExporter::Format format =
@@ -98,7 +116,8 @@ void VideoExportDialog::updateUi()
 		}
 		args.append({"-y", "<FILENAME>"});
 
-		m_ui->ffmpegBasics->setText("ffmpeg " + args.join(QChar(' ')));
+		m_ui->ffmpegBasics->setText(QStringLiteral("%1 %2").arg(
+			getFfmpegPath(), args.join(QChar(' '))));
 		m_ui->ffmpegCustomLabel->setVisible(format == VideoExporter::FFMPEG_CUSTOM);
 		m_ui->ffmpegCustom->setVisible(format == VideoExporter::FFMPEG_CUSTOM);
 	}
@@ -136,6 +155,12 @@ VideoExporter *VideoExportDialog::getExporter()
 	return ve;
 }
 
+QString VideoExportDialog::getFfmpegPath()
+{
+	QString path = m_ui->ffmpegPathEdit->text().trimmed();
+	return path.isEmpty() ? QStringLiteral("ffmpeg") : path;
+}
+
 VideoExporter *VideoExportDialog::getImageSeriesExporter()
 {
 	QString dir = FileWrangler{this}.getSaveAnimationFramesPath();
@@ -166,7 +191,8 @@ VideoExporter *VideoExportDialog::getFfmpegExporter(VideoExporter::Format format
 		return nullptr;
 	} else {
 		return new FfmpegExporter{
-			format, filename, m_ui->ffmpegCustom->toPlainText()};
+			format, getFfmpegPath(), filename,
+			m_ui->ffmpegCustom->toPlainText()};
 	}
 }
 

src/desktop/dialogs/videoexportdialog.h

@@ -24,9 +24,11 @@ class VideoExportDialog final : public QDialog
 	VideoExporter *getExporter();
 
 private slots:
+	void chooseFfmpegPath();
 	void updateUi();
 
 private:
+	QString getFfmpegPath();
 	VideoExporter *getImageSeriesExporter();
 	VideoExporter *getFfmpegExporter(VideoExporter::Format format);
 

src/desktop/settings_table.h

@@ -139,6 +139,7 @@ SETTING(twoFingerRotate           , TwoFingerRotate           , "settings/input/
 SETTING(twoFingerZoom             , TwoFingerZoom             , "settings/input/touchpinch"             , true)
 SETTING(updateCheckEnabled        , UpdateCheckEnabled        , "settings/updatecheck"                  , true)
 SETTING(videoExportCustomFfmpeg   , VideoExportCustomFfmpeg   , "videoexport/customffmpeg"              , QString())
+SETTING(videoExportFfmpegPath     , VideoExportFfmpegPath     , "videoexport/ffmpegpath"                , QString("ffmpeg"))
 SETTING(videoExportFormat         , VideoExportFormat         , "videoexport/formatchoice"              , VideoExporter::Format::IMAGE_SERIES)
 SETTING(videoExportFrameHeight    , VideoExportFrameHeight    , "videoexport/frameheight"               , 720)
 SETTING(videoExportFrameRate      , VideoExportFrameRate      , "videoexport/fps"                       , 30)