RTSP stream的轻量级编码方法？

Question

what i am trying to do is to save a RTSP-stream as a file with some text overlay (so copy is not an option) on a Raspberry Pi. I tried using FFMPEG, but even with ultrafast settings the CPU load is way too high. Is there a faster encoding method or a completely different approach that i am missing?

ffmpeg -rtsp_transport tcp -i rtsp://x:y@ip/stream1 -vcodec libx264 -preset ultrafast -crf 0 -segment_time 3600 -t 3600 -f segment -y -strftime 1 -vf drawtext="fontcolor=white:fontsize=30:text='%{localtime}'",drawtext="fontcolor=white:fontsize=30:textfile=text.txt:x=600" /home/pi/NAS1/Elements/Videos/%Y-%m-%d_%H-%M-%S_file.mp4

Answer 1

Use the hardware encoder

Ie

ffmpeg -codec:v h264_omx -b:v 2048k