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

Michael Niedermayer michaelni
Tue May 25 23:30:25 CEST 2010

On Tue, May 25, 2010 at 10:40:29PM +0200, Sven Brandau wrote:
> Hi,
> I've tried to encode a very unpredictable and varying video to MPEG-2 video 
> in CBR. It seems that the encoder can't regulate the bitrate so there are 
> spikes where the scenes changes very fast. I would expect that the encoder 
> is able to control all parameters, e.g. quantizer, to fit the bitrate 
> without such spikes but a very low video quality on such scene changes.
> I've set these parameters: bitrate, max/min bitrate, vbv buffer
> Any suggestions?

cbr (constant bitrate) does not mean constant framesize
the bitrate that enters the vbv should be constant

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


Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

When you are offended at any man's fault, turn to yourself and study your
own failings. Then you will forget your anger. -- Epictetus
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: Digital signature
URL: <http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/attachments/20100525/fd26eda1/attachment.pgp>

More information about the ffmpeg-devel mailing list