- Grafische Ausgabe kann nun als Video aufgezeichnet werden

- Verbindung über TCP/IP

include/videowidget.h

@@ -1,15 +1,22 @@
 #pragma once
 #include <QWidget>
 #include <QImage>
+#include <QSize>
 #include <QLabel>
 #include <QPushButton>
 #include <QComboBox>
 #include <QHBoxLayout>
 #include <QVBoxLayout>
 #include <QThread>
+#include <QProcess>
 
 #include "v4l2worker.h"
 
+// VideoWidget shows the live V4L2 preview and can additionally record it
+// to an MP4 file. Recording works by piping raw BGRA frames into an
+// external `ffmpeg` process (via QProcess/stdin), which encodes them to
+// H.264/MP4 - this avoids reimplementing video encoding and just needs
+// ffmpeg to be installed and on PATH.
 class VideoWidget : public QWidget
 {
     Q_OBJECT
@@ -29,6 +36,7 @@ private slots:
     void onStartStop();
     void onFreeze(bool frozen);
     void onScreenshot();
+    void onRecordToggled(bool checked);
     void refreshDeviceList();
 
 protected:
@@ -40,6 +48,9 @@ private:
     void startCapture();
     void stopCapture();
     void updateScaled();
+    void startRecording();
+    void stopRecording();
+    void writeRecordingFrame(const QImage &frame);
 
     QThread     *m_thread = nullptr;
     V4l2Worker  *m_worker = nullptr;
@@ -54,5 +65,15 @@ private:
     QPushButton *m_startBtn      = nullptr;
     QPushButton *m_freezeBtn     = nullptr;
     QPushButton *m_screenshotBtn = nullptr;
+    QPushButton *m_recordBtn     = nullptr;
     QLabel      *m_infoLabel     = nullptr;
+
+    // Recording state. m_recordProcess is the running ffmpeg instance (or
+    // nullptr when not recording); m_recordSize is the frame size the
+    // recording was started with, so a mid-stream resolution change (which
+    // ffmpeg's raw pipe can't handle) can be detected and the recording
+    // stopped cleanly instead of corrupting the output file.
+    QProcess *m_recordProcess = nullptr;
+    bool      m_recording     = false;
+    QSize     m_recordSize;
 };