[Ffmpeg-devel] ratecontrol advice

Rich Felker dalias
Tue May 10 18:06:08 CEST 2005


On Tue, May 10, 2005 at 12:55:44AM -0700, Loren Merritt wrote:
> (Warning: anything done by a 1pass encode will be an approximate/soft 
> limit, since you don't know in advance excatly how many bits a given QP 
> will take. So you'll need to fudge the limit a little if you care about 
> strict compliance.)

While true, this isn't an inherent limitation, just a flaw in lavc's
rate control engine. It's easy to implement strict limits in 1pass
encoding: just repeatedly reencode the frame at different values of qp
until you find one that gives the size you want. With binary search it
shouldn't even be that slow...

Rich





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