Qt: Automatically change video file extension as appropriate

CHANGES

@@ -19,6 +19,7 @@ Other fixes:
 Misc:
  - Qt: Include wayland QPA in AppImage (fixes mgba.io/i/2796)
  - Qt: Stop eating boolean action key events (fixes mgba.io/i/2636)
+ - Qt: Automatically change video file extension as appropriate
 
 0.10.1: (2023-01-10)
 Emulation fixes:

src/platform/qt/VideoView.cpp

@@ -20,6 +20,7 @@ using namespace QGBA;
 QMap<QString, QString> VideoView::s_acodecMap;
 QMap<QString, QString> VideoView::s_vcodecMap;
 QMap<QString, QString> VideoView::s_containerMap;
+QMap<QString, QStringList> VideoView::s_extensionMap;
 
 bool VideoView::Preset::compatible(const Preset& other) const {
 	if (!other.container.isNull() && !container.isNull() && other.container != container) {
@@ -71,6 +72,23 @@ VideoView::VideoView(QWidget* parent)
 	if (s_containerMap.empty()) {
 		s_containerMap["mkv"] = "matroska";
 	}
+	if (s_extensionMap.empty()) {
+		s_extensionMap["matroska"] += ".mkv";
+		s_extensionMap["matroska"] += ".mka";
+		s_extensionMap["webm"] += ".webm";
+		s_extensionMap["avi"] += ".avi";
+		s_extensionMap["mp4"] += ".mp4";
+		s_extensionMap["mp4"] += ".m4v";
+		s_extensionMap["mp4"] += ".m4a";
+
+		s_extensionMap["flac"] += ".flac";
+		s_extensionMap["mpeg"] += ".mpg";
+		s_extensionMap["mpeg"] += ".mpeg";
+		s_extensionMap["mpegts"] += ".ts";
+		s_extensionMap["mp3"] += ".mp3";
+		s_extensionMap["ogg"] += ".ogg";
+		s_extensionMap["ogv"] += ".ogv";
+	}
 
 	connect(m_ui.buttonBox, &QDialogButtonBox::rejected, this, &VideoView::close);
 	connect(m_ui.start, &QAbstractButton::clicked, this, &VideoView::startRecording);
@@ -195,6 +213,9 @@ void VideoView::setController(std::shared_ptr<CoreController> controller) {
 }
 
 void VideoView::startRecording() {
+	if (QFileInfo(m_filename).suffix().isEmpty()) {
+		changeExtension();
+	}
 	if (!validateSettings()) {
 		return;
 	}
@@ -238,6 +259,7 @@ void VideoView::selectFile() {
 	QString filename = GBAApp::app()->getSaveFileName(this, tr("Select output file"));
 	if (!filename.isEmpty()) {
 		m_ui.filename->setText(filename);
+		changeExtension();
 	}
 }
 
@@ -289,6 +311,7 @@ void VideoView::setContainer(const QString& container) {
 		m_containerCstr = nullptr;
 		m_container = QString();
 	}
+	changeExtension();
 	validateSettings();
 	uncheckIncompatible();
 }
@@ -458,6 +481,30 @@ void VideoView::uncheckIncompatible() {
 	}
 }
 
+void VideoView::changeExtension() {
+	if (m_filename.isEmpty()) {
+		return;
+	}
+
+	if (!s_extensionMap.contains(m_container)) {
+		return;
+	}
+
+	QStringList extensions = s_extensionMap.value(m_container);
+	QString filename = m_filename;
+	int index = m_filename.lastIndexOf(".");
+	if (index >= 0) {
+		if (extensions.contains(filename.mid(index))) {
+			// This extension is already valid
+			return;
+		}
+		filename.truncate(index);
+	}
+	filename += extensions.front();
+
+	m_ui.filename->setText(filename);
+}
+
 QString VideoView::sanitizeCodec(const QString& codec, const QMap<QString, QString>& mapping) {
 	QString sanitized = codec.toLower();
 	sanitized = sanitized.remove(QChar('.'));

src/platform/qt/VideoView.h

@@ -7,6 +7,7 @@
 
 #ifdef USE_FFMPEG
 
+#include <QStringList>
 #include <QWidget>
 
 #include <memory>
@@ -62,6 +63,8 @@ private slots:
 	void uncheckIncompatible();
 	void updatePresets();
 
+	void changeExtension();
+
 private:
 	struct Preset {
 		QString container;
@@ -123,6 +126,7 @@ private:
 	static QMap<QString, QString> s_acodecMap;
 	static QMap<QString, QString> s_vcodecMap;
 	static QMap<QString, QString> s_containerMap;
+	static QMap<QString, QStringList> s_extensionMap;
 };
 
 }