[MPlayer-cvslog] CVS: main/libmpcodecs ve_lavc.c,1.111,1.112

D Richard Felker III dalias at aerifal.cx
Fri Mar 4 02:57:43 CET 2005

On Thu, Mar 03, 2005 at 05:42:05PM -0800, Loren Merritt wrote:
> On Thu, 3 Mar 2005, D Richard Felker III wrote:
> >On Thu, Mar 03, 2005 at 04:26:42PM -0800, Loren Merritt wrote:
> >
> >>(However, constant quality does not mean constant PSNR nor
> >>constant QP.
> >
> >I'd be very interested in a constant-PSNR rate control engine, to see
> >how it would perform in terms of perceptual quality..
> Constant PSNR means lower QP in high complexity frames than in low 
> complexity. The only cases where I've seen constant PSNR proposed were in 
> codecs that don't use scalar quantizers: Some alternatives like bitplane 
> coding allow you to see the whole rate-distortion curve of a frame before 
> deciding how many bits to give it. But that's not applicable to mpeg-like 
> codecs.

It might make sense if you're using insane bitrates (i.e. qp=1 or 2
most of the time already) and you want to make a near-lossless encode
for archival use or for later encoding to another format.


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