[FFmpeg-devel] [DOC] FFSERVER Configuration Files.

Piero Bugoni ffmpeg.devel
Sat Sep 1 01:03:57 CEST 2007

Did some testing recently:

Example Bitrates:
(CIF size, 29.97 fps).

Pure-Blue, no-input signal when camera is disconnected:
around 65 to 100 kbps

An ordinary white wall, some texture, ordinary lighting, no movement:
165 to 225 kbps

White Noise:
1200 kbps 

These were the sorts of rates that result when no "Qmin|Qmax" is specified, (in
ffserver.conf, or on the command line). I am not sure at this point that the
"Q" values reported on the command line by ffmpeg are correct.

When changing between images ffmpeg did not adjust bitrates very much. But
after stopping and resarting, it would adjust itself to the rates mentioned.

I could not tell if setting VideoBitRateRange had any effect.

I was able to get a decent video (CIF size, 3 fps) of a desk and computer
screen across the ADSL line at  around 320 kbps by setting Qmin/Qmax to
particular ranges like 1-3, or 3-6, 5-9, etc. By starting with these values
unset, then setting them across a range, you can "tune" the bitrate some to
your available bandwidth.

I cant tell right now how much ffmpeg/ffserver can react to major changes in a
stream that affect bitrate. When the camera went from no-input to white-noise,
the stream just stopped.


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