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>

3 files changed, 103 insertions, 1 deletions

diff --git a/desktop-widgets/preferences/preferences_defaults.cpp b/desktop-widgets/preferences/preferences_defaults.cpp
index a7b5e4c1d..4d8aef610 100644
--- a/desktop-widgets/preferences/preferences_defaults.cpp
+++ b/desktop-widgets/preferences/preferences_defaults.cpp
@@ -43,6 +43,22 @@ void PreferencesDefaults::on_localDefaultFile_toggled(bool toggle)
 	ui->chooseFile->setEnabled(toggle);
 }
 
+void PreferencesDefaults::on_ffmpegFile_clicked()
+{
+	QFileInfo fi(system_default_filename());
+	QString ffmpegFileName = QFileDialog::getOpenFileName(this, tr("Select ffmpeg executable"));
+
+	if (!ffmpegFileName.isEmpty())
+		ui->ffmpegExecutable->setText(ffmpegFileName);
+}
+
+void PreferencesDefaults::on_extractVideoThumbnails_toggled(bool toggled)
+{
+	ui->videoThumbnailPosition->setEnabled(toggled);
+	ui->ffmpegExecutable->setEnabled(toggled);
+	ui->ffmpegFile->setEnabled(toggled);
+}
+
 void PreferencesDefaults::refreshSettings()
 {
 	ui->font->setCurrentFont(QString(prefs.divelist_font));
@@ -73,6 +89,14 @@ void PreferencesDefaults::refreshSettings()
 	ui->defaultfilename->setEnabled(prefs.default_file_behavior == LOCAL_DEFAULT_FILE);
 	ui->btnUseDefaultFile->setEnabled(prefs.default_file_behavior == LOCAL_DEFAULT_FILE);
 	ui->chooseFile->setEnabled(prefs.default_file_behavior == LOCAL_DEFAULT_FILE);
+
+	ui->videoThumbnailPosition->setEnabled(prefs.extract_video_thumbnails);
+	ui->ffmpegExecutable->setEnabled(prefs.extract_video_thumbnails);
+	ui->ffmpegFile->setEnabled(prefs.extract_video_thumbnails);
+
+	ui->extractVideoThumbnails->setChecked(prefs.extract_video_thumbnails);
+	ui->videoThumbnailPosition->setValue(prefs.extract_video_thumbnails_position);
+	ui->ffmpegExecutable->setText(prefs.ffmpeg_executable);
 }
 
 void PreferencesDefaults::syncSettings()
@@ -87,6 +111,9 @@ void PreferencesDefaults::syncSettings()
 		general->setDefaultFileBehavior(LOCAL_DEFAULT_FILE);
 	else if (ui->cloudDefaultFile->isChecked())
 		general->setDefaultFileBehavior(CLOUD_DEFAULT_FILE);
+	general->setExtractVideoThumbnails(ui->extractVideoThumbnails->isChecked());
+	general->setExtractVideoThumbnailsPosition(ui->videoThumbnailPosition->value());
+	general->setFfmpegExecutable(ui->ffmpegExecutable->text());
 
 	auto display =  qPrefDisplay::instance();
 	display->set_divelist_font(ui->font->currentFont().toString());
diff --git a/desktop-widgets/preferences/preferences_defaults.h b/desktop-widgets/preferences/preferences_defaults.h
index 1674dd2ad..d7bb7db7f 100644
--- a/desktop-widgets/preferences/preferences_defaults.h
+++ b/desktop-widgets/preferences/preferences_defaults.h
@@ -20,6 +20,8 @@ public slots:
 	void on_chooseFile_clicked();
 	void on_btnUseDefaultFile_toggled(bool toggled);
 	void on_localDefaultFile_toggled(bool toggled);
+	void on_ffmpegFile_clicked();
+	void on_extractVideoThumbnails_toggled(bool toggled);
 
 private:
 	Ui::PreferencesDefaults *ui;
diff --git a/desktop-widgets/preferences/preferences_defaults.ui b/desktop-widgets/preferences/preferences_defaults.ui
index 1a54d7b0a..731eed6ab 100644
--- a/desktop-widgets/preferences/preferences_defaults.ui
+++ b/desktop-widgets/preferences/preferences_defaults.ui
@@ -73,7 +73,7 @@
         <item>
          <widget class="QRadioButton" name="noDefaultFile">
           <property name="text">
-           <string>No default file</string>
+           <string>&amp;No default file</string>
           </property>
          </widget>
         </item>
@@ -210,6 +210,79 @@
     </widget>
    </item>
    <item>
+    <widget class="QGroupBox" name="groupBox_10">
+     <property name="title">
+      <string>Video thumbnails</string>
+     </property>
+     <layout class="QFormLayout" name="formLayout">
+      <property name="horizontalSpacing">
+       <number>5</number>
+      </property>
+      <property name="verticalSpacing">
+       <number>5</number>
+      </property>
+      <property name="margin">
+       <number>5</number>
+      </property>
+      <item row="1" column="0">
+       <widget class="QLabel" name="ffmpegExectuableLabel">
+        <property name="text">
+         <string>ffmpeg executable</string>
+        </property>
+       </widget>
+      </item>
+      <item row="1" column="1">
+       <layout class="QHBoxLayout" name="horizontalLayout_3b">
+        <item>
+         <widget class="QLineEdit" name="ffmpegExecutable"/>
+        </item>
+        <item>
+         <widget class="QToolButton" name="ffmpegFile">
+          <property name="text">
+           <string>...</string>
+          </property>
+         </widget>
+        </item>
+       </layout>
+      </item>
+      <item row="3" column="0">
+       <widget class="QLabel" name="videoThumbnailPositionLabel">
+        <property name="text">
+         <string>Extract at position</string>
+        </property>
+       </widget>
+      </item>
+      <item row="3" column="1">
+       <widget class="QSlider" name="videoThumbnailPosition">
+        <property name="maximum">
+         <number>100</number>
+        </property>
+        <property name="value">
+         <number>20</number>
+        </property>
+        <property name="orientation">
+         <enum>Qt::Horizontal</enum>
+        </property>
+       </widget>
+      </item>
+      <item row="0" column="0">
+       <widget class="QLabel" name="extractVideoThumbnailsLabel">
+        <property name="text">
+         <string>Extract video thumbnails</string>
+        </property>
+       </widget>
+      </item>
+      <item row="0" column="1">
+       <widget class="QCheckBox" name="extractVideoThumbnails">
+        <property name="text">
+         <string/>
+        </property>
+       </widget>
+      </item>
+     </layout>
+    </widget>
+   </item>
+   <item>
     <widget class="QGroupBox" name="groupBox_9">
      <property name="title">
       <string>Clear all settings</string>