[FFmpeg-user] Meaning of key/values in output of progress option

[Konrad Reiche]

Hi,

the -progress [URI] options allows to post progress metadata to an 
endpoint. The output roughly correlates with the one printed to stderr 
in verbose mode of ffmpeg:

8f
frame=91
fps=0.0
stream_0_0_q=23.0
total_size=205437
out_time_ms=4388571
out_time=00:00:04.388571
dup_frames=1
drop_frames=0
progress=continue


Where can I learn about the meaning of the key/value pairs produced 
there? Is this documented somewhere. Apparently the q stands for 
quantizer of the codec?

I am specifically interested about speed and progress/time.

What can I learn from these values? I need this for monitoring purposes 
of the health/quality of the running ffmpeg transcoding. Should I look 
at any other values?

Best,
Konrad