[FFmpeg-user] Receive network stream and drop without decoding

[Andrius Narbutas]

Looks like there is a way to sync ffmpeg with stream speed, so it does 
not try to go as fast as possible - it's "-re".
So far so good, 1080p DASH live stream works with below 1%/core:

ffmpeg -re -i "input_stream" -c copy -map 0:v:6 -f null -

I see network traffic (10Mbps) and, based on consumption - can fit 
probably thousand or more copies to make proper load generator for server.
perf report shows that most load comes from libc functions, so probably 
nothing to optimize on ffmpeg side already (network traffic).

So far - so good, thanks to all who helped! ;-)