Dive media: Extract thumbnails from videos with ffmpeg

Extract thumbnails using ffmpeg.
Behavior is controlled by three new preferences fields:
 - extract_video_thumbnails (bool): if true, thumbnails are calculated.
 - extract_video_thumbnail_position (int 0..100): position in video
   where thumbnail is fetched.
 - ffmpeg_executable (string): path of ffmpeg executable.

If ffmpeg refuses to start, extract_video_thumbnails is set to false
to avoid unnecessary churn.

Video thumbnails are marked by an overlay.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

2 files changed, 72 insertions, 8 deletions

diff --git a/core/subsurface-qt/SettingsObjectWrapper.cpp b/core/subsurface-qt/SettingsObjectWrapper.cpp
index 3085216c7..da2a86a68 100644
--- a/core/subsurface-qt/SettingsObjectWrapper.cpp
+++ b/core/subsurface-qt/SettingsObjectWrapper.cpp
@@ -1474,6 +1474,21 @@ bool GeneralSettingsObjectWrapper::autoRecalculateThumbnails() const
 	return prefs.auto_recalculate_thumbnails;
 }
 
+bool GeneralSettingsObjectWrapper::extractVideoThumbnails() const
+{
+	return prefs.extract_video_thumbnails;
+}
+
+int GeneralSettingsObjectWrapper::extractVideoThumbnailsPosition() const
+{
+	return prefs.extract_video_thumbnails_position;
+}
+
+QString GeneralSettingsObjectWrapper::ffmpegExecutable() const
+{
+	return prefs.ffmpeg_executable;
+}
+
 void GeneralSettingsObjectWrapper::setDefaultFilename(const QString& value)
 {
 	if (value == prefs.default_filename)
@@ -1579,6 +1594,43 @@ void GeneralSettingsObjectWrapper::setAutoRecalculateThumbnails(bool value)
 	emit autoRecalculateThumbnailsChanged(value);
 }
 
+void GeneralSettingsObjectWrapper::setExtractVideoThumbnails(bool value)
+{
+	if (value == prefs.extract_video_thumbnails)
+		return;
+
+	QSettings s;
+	s.beginGroup(group);
+	s.setValue("extract_video_thumbnails", value);
+	prefs.extract_video_thumbnails = value;
+	emit extractVideoThumbnailsChanged(value);
+}
+
+void GeneralSettingsObjectWrapper::setExtractVideoThumbnailsPosition(int value)
+{
+	if (value == prefs.extract_video_thumbnails_position)
+		return;
+
+	QSettings s;
+	s.beginGroup(group);
+	s.setValue("extract_video_thumbnails_position", value);
+	prefs.extract_video_thumbnails_position = value;
+	emit extractVideoThumbnailsPositionChanged(value);
+}
+
+void GeneralSettingsObjectWrapper::setFfmpegExecutable(const QString &value)
+{
+	if (value == prefs.ffmpeg_executable)
+		return;
+
+	QSettings s;
+	s.beginGroup(group);
+	s.setValue("ffmpeg_executable", value);
+	free((void *)prefs.ffmpeg_executable);
+	prefs.ffmpeg_executable = copy_qstring(value);
+	emit ffmpegExecutableChanged(value);
+}
+
 LanguageSettingsObjectWrapper::LanguageSettingsObjectWrapper(QObject *parent) :
 	QObject(parent)
 {
diff --git a/core/subsurface-qt/SettingsObjectWrapper.h b/core/subsurface-qt/SettingsObjectWrapper.h
index cd30cb1ac..a7957f9f1 100644
--- a/core/subsurface-qt/SettingsObjectWrapper.h
+++ b/core/subsurface-qt/SettingsObjectWrapper.h
@@ -435,14 +435,17 @@ private:
 
 class GeneralSettingsObjectWrapper : public QObject {
 	Q_OBJECT
-	Q_PROPERTY(QString default_filename         READ defaultFilename           WRITE setDefaultFilename           NOTIFY defaultFilenameChanged)
-	Q_PROPERTY(QString default_cylinder         READ defaultCylinder           WRITE setDefaultCylinder           NOTIFY defaultCylinderChanged)
-	Q_PROPERTY(short default_file_behavior      READ defaultFileBehavior       WRITE setDefaultFileBehavior       NOTIFY defaultFileBehaviorChanged)
-	Q_PROPERTY(bool use_default_file            READ useDefaultFile            WRITE setUseDefaultFile            NOTIFY useDefaultFileChanged)
-	Q_PROPERTY(int defaultsetpoint              READ defaultSetPoint           WRITE setDefaultSetPoint           NOTIFY defaultSetPointChanged)
-	Q_PROPERTY(int o2consumption                READ o2Consumption             WRITE setO2Consumption             NOTIFY o2ConsumptionChanged)
-	Q_PROPERTY(int pscr_ratio                   READ pscrRatio                 WRITE setPscrRatio                 NOTIFY pscrRatioChanged)
-	Q_PROPERTY(bool auto_recalculate_thumbnails READ autoRecalculateThumbnails WRITE setAutoRecalculateThumbnails NOTIFY autoRecalculateThumbnailsChanged)
+	Q_PROPERTY(QString default_filename              READ defaultFilename                WRITE setDefaultFilename                NOTIFY defaultFilenameChanged)
+	Q_PROPERTY(QString default_cylinder              READ defaultCylinder                WRITE setDefaultCylinder                NOTIFY defaultCylinderChanged)
+	Q_PROPERTY(short default_file_behavior           READ defaultFileBehavior            WRITE setDefaultFileBehavior            NOTIFY defaultFileBehaviorChanged)
+	Q_PROPERTY(bool use_default_file                 READ useDefaultFile                 WRITE setUseDefaultFile                 NOTIFY useDefaultFileChanged)
+	Q_PROPERTY(int defaultsetpoint                   READ defaultSetPoint                WRITE setDefaultSetPoint                NOTIFY defaultSetPointChanged)
+	Q_PROPERTY(int o2consumption                     READ o2Consumption                  WRITE setO2Consumption                  NOTIFY o2ConsumptionChanged)
+	Q_PROPERTY(int pscr_ratio                        READ pscrRatio                      WRITE setPscrRatio                      NOTIFY pscrRatioChanged)
+	Q_PROPERTY(bool auto_recalculate_thumbnails      READ autoRecalculateThumbnails      WRITE setAutoRecalculateThumbnails      NOTIFY autoRecalculateThumbnailsChanged)
+	Q_PROPERTY(bool extract_video_thumbnails         READ extractVideoThumbnails         WRITE setExtractVideoThumbnails         NOTIFY extractVideoThumbnailsChanged)
+	Q_PROPERTY(int extract_video_thumbnails_position READ extractVideoThumbnailsPosition WRITE setExtractVideoThumbnailsPosition NOTIFY extractVideoThumbnailsPositionChanged)
+	Q_PROPERTY(QString ffmpeg_executable             READ ffmpegExecutable               WRITE setFfmpegExecutable               NOTIFY ffmpegExecutableChanged)
 
 public:
 	GeneralSettingsObjectWrapper(QObject *parent);
@@ -454,6 +457,9 @@ public:
 	int o2Consumption() const;
 	int pscrRatio() const;
 	bool autoRecalculateThumbnails() const;
+	bool extractVideoThumbnails() const;
+	int extractVideoThumbnailsPosition() const;
+	QString ffmpegExecutable() const;
 
 public slots:
 	void setDefaultFilename           (const QString& value);
@@ -464,6 +470,9 @@ public slots:
 	void setO2Consumption             (int value);
 	void setPscrRatio                 (int value);
 	void setAutoRecalculateThumbnails (bool value);
+	void setExtractVideoThumbnails    (bool value);
+	void setExtractVideoThumbnailsPosition (int value);
+	void setFfmpegExecutable          (const QString &value);
 
 signals:
 	void defaultFilenameChanged(const QString& value);
@@ -474,6 +483,9 @@ signals:
 	void o2ConsumptionChanged(int value);
 	void pscrRatioChanged(int value);
 	void autoRecalculateThumbnailsChanged(int value);
+	void extractVideoThumbnailsChanged(bool value);
+	void extractVideoThumbnailsPositionChanged(int value);
+	void ffmpegExecutableChanged(const QString &value);
 private:
 	const QString group = QStringLiteral("GeneralSettings");
 };