[FFmpeg-user] ffmpeg for rate adaptive experiments

Carl Eugen Hoyos cehoyos at ag.or.at
Wed Nov 16 17:54:56 CET 2011

Ingemar Johansson S <ingemar.s.johansson <at> ericsson.com> writes:

> I am looking for a simple way to visualize an encoding scenario where the
> target bitrate varies with time. The typical use case is a rate adaptive video
> for a realtime interactive service where the bitrate is determined by channel
> conditions. Typically it should be possible to change the bitrate once per
> second or possibly more often.
> I would like to visualize packet loss and delay as well, in short I want to
> demo the cases
> 1) No rate adaptation e.g 384kbps
> 2) Rate adaptation e.g between 64 and 384kpbs

> The demo should give answers to the questions how is video quality affect by
> the packet delay packet drops
> and the bitrate as a reult of the two approaches above, I get the the bitrate
> and delay traces from a proprietary system simulator.
> Is there a possiblity to use ffmpeg for this purpose ?

Why not?
Afaik, you can set the target bitrate for every frame (that may not make much
sense, but at least for every gop should be no problem), it should be sufficient
to program your encoder (that uses libavcodec) to feed the requested bitrates
from the system simulator to the rate control (that may or may not work
sufficiently exact for your requirements).

Carl Eugen

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