[MEncoder-users] lavc or xvid

[Phil Ehrens]

Alex Samad wrote:
> On Wed, Sep 05, 2007 at 08:45:03AM -0700, Phil Ehrens wrote:
> > RC wrote:
> > > On Tue, 4 Sep 2007 16:08:40 -0700
> > > Phil Ehrens <phil at slug.org> wrote:
> > > 
> > > > Eek! nr=300?! Alright, I admit it... I reported the same thing
> > > > once (or twice). If the source genuinely has significant gaussian
> > > > noise, nr=300 can perform miracles... HOWEVER, if you are starting
> > > > with good clean source (like a well-made dvd), nr=10 to nr=30 is
> > > > more realistic.
> > > 
> > > Almost every DVD I've seen has significant noise, and nr=300 helps a
> > > lot (and I've done several visual and PSNR tests to demonstrate that).
> > > That even goes for the newest digitally-recorded films. The few DVDs
> > > that don't have noise really stand out as unusually clear (appearing
> > > almost fake or cartoon-like), and in most cases, was a direct result of
> > > heavily denoising before encoding.
> > 
> > Maybe we are at odds here because of target bitrate? I can see
> > where nr=300 might be a typical setting if the target bitrate
> > is 600-800 kbps. Using nr=10 would be practically pointless
> > at those bitrates. Ah well, that's the danger of recommending
> > values for things like this... Too many independent variables.
> 
> So maybe the question to be asked is what I should expect from xvid, lavc from
> a mpeg-2 video recorder source.  If I start with a 50Mb file that is shot 
> around the house, sometimes inside sometimes outside, what sort of file size 
> would you expect to see (guestimate), from my simple trials I have done, the 
> bitrate I am looking at is ~ 2000 and I will end up with a file size that is 
> approx 50% the size.  the other bitrates do produce smaller files, but I get 
> lots of artifacts - especially around lots of solid colour like white walls
> etc.

Just my opinion, but for shots around the house, 1200 is
probably more than sufficient, with the "right options".
It took me a very long time to decide what were those
options were *for me*... I'll be conservative and say
that with lavc, a two pass mpeg4 encode to 1200, with
mbd=2:v4mv:trell and nr=50,nr=200,nr=400 might give you
something to ponder. Since I am guessing your source
isn't spectacular, I don't think any of the more "tweaky"
options is going to help much in this case.

I think I have forgotten what this thread was originally
about. I hope I haven't strayed too far off topic, or
confused anybody other than myself.