[Ffmpeg-devel] Bad interation of rc_strategy=1 and qprd (original) (raw)

Michael Niedermayer michaelni
Mon Feb 6 02:25:32 CET 2006

Hi

On Sun, Feb 05, 2006 at 10:12:06PM +0100, Nico Sabbi wrote:

Loren Merritt wrote:

>On Sat, 4 Feb 2006, Nico Sabbi wrote: > >>Michael Niedermayer wrote: >> >>> >>>well, you at least have to post 1st pass, 2nd pass stats of lavc, >>>lavc+xvidrc >>>and xvid ... >> >> >>I'm not comparing the two codecs (I prefer lavc much more than xvid): >>I'm only encoding to lavc (mpeg2) with and without vrcstrategy=1 to >>see if there is any improvement. >>I'll post the psnr figures when I've collected them > > >But you should compare lavc+xvidrc against xvid+xvidrc, otherwise >you won't know if you've accurately implemented xvidrc. > >First guess for why qprd borks: did you not set lambda appropriately? >xvid's rc deals only with quantizers. > >--Loren Merritt > here are the results; if you need more tests let me know. Visually mpeg4 looks much better to my eyes, both with vrcstrategy=0 and with vrcstrategy=1.

hmm, just to make sure ... your xvid version is upto date head cvs?

PSNR figures for vcodec=xvid are not available.

thats bad, without PSNR stats its hard to know if xvid_rc is buggy or not you should also run the first pass for xvid_rc with qscale=2, as thats what xvid does ...

[...]

-- Michael

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