[FFmpeg-devel] CBR Bitrate control in MPEG-2 video encoder

Sven Brandau wasisnlos
Wed May 26 21:22:18 CEST 2010

Am 25.05.2010 23:30, schrieb Michael Niedermayer:
> cbr (constant bitrate) does not mean constant framesize
> the bitrate that enters the vbv should be constant
And how are you measure the bitrate? In a very simple way you will take 
the whole time of the video stream and calculate the bitrate from file 
size. The only question is (beside the vbv constrains) how small is the 
time unit in which the bitrate will be calculated. 1s? 30s? ...?

> and only a true mpeg2 stream analyzer can tell you the bitrate prior to
> the vbv. Your mail does not sound like you used such a tool
You are right, I don't have such a tool. Have you ever tried such a tool 
on the ffmpeg MPEG-2 video encoder?

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