[Libav-user] H264 encoding: set target average bitrate

Andrey Utkin andrey.krieger.utkin at gmail.com
Mon Oct 17 18:12:54 CEST 2011

I do encoding h264 video in my app that uses libavcodec (git almost
HEAD (f22bc68 Oct, 7), x264 git almost HEAD too(8a62835 Sep, 14)). I
set to output AVCodecContext options bit_rate, rc_buffer_size,
rc_max_rate, rc_min_rate (see line 142), but they seem to be not
affecting the process - i get output video bitrate too much highter.
Additionally, i set qmin=qmax=-1 (without setting them libx264 rejects
to work lamenting about broken defaults). When i set them to
positives, the bitrate changes. Seems i can control bitrate by
qmin,qmax setting only, what is certainly not acceptable.
My sources: https://github.com/krieger-od/transcoder/blob/master/transcoder.c .
Any comments are appreciated.
Andrey Utkin

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