save timelapse stream to file

src/app.h

@@ -96,7 +96,6 @@ public:
     std::mutex rec_mutex;
     std::condition_variable rec_cv;
     std::deque<std::unique_ptr<Image>> rec_frames;
-    std::unique_ptr<MP4Encoder> m_encoder;
 
     RTT uirtt;
     Sampler sampler;