=> lower compile time on changes in data structure

 - multithreaded encoding (sending frames to encoder and receiving and writing packets is now splitted)
 - speed is now sufficient, even at very throttled cpu, efficiency of pix format conversion requires improvements (10 % cpu usage is too much)
 - todo: multithreaded decoding (same splitting as encoding)

 - VAAPI decode working
 - VAAPI encode working (split frame sending and packet receiving into separate threads)