[MEncoder-users] NTSC and Questions about quality

[Pete Davis]

> Hi,
> 
> On 7/25/05, Pete Davis <pete at petedavis.net> wrote:
> > The main thing I'm using mencoder for these days is encoding stuff I'm
> > capturing off of my DirectTV dish.
> >
> > I'm generally using lavc a bitrate of 1100. The only non-default options
> in
> > regards to quality that I have are keyint=30 and mbd=2.
> 
> 1100 is a fairly high bitrate, so you should get a fairly decent
> quality, but quality depends on the size of the video you encode too
> (among other things).

1100 works out really well. I can usually get 4 movies to a DVD with that. I
think the original mpeg2 from the Hauppauge is recorded at a bitrate of
1200.

> 
> 
> > I've been messing around with some other options, such as nr=400, trell,
> > trell and cbp. But the truth is, I can't see any noticeable difference
> at
> > all from these options, even on my computer (which has a much better
> image
> > than the TV, of course). Except for some slight blocky pixilation with
> large
> > solid colors (especially darker colors), the encodings with mbd=2 are
> just
> > about as good as the original broadcast. I suppose that with DVDs, where
> the
> > original image quality is so high, these options probably have a bit
> more of
> > an impact, but for NTSC stuff, I just can't see it.
> >
> > Are there options for handling the blocky pixilation? It's not
> noticeable
> > enough that I'm willing to sacrifice much in terms of encoding speed to
> get
> > rid of it.
> 
> Yep, video encoding is all about personal tastes. If you see no
> artifact with your setting, then just be happy with it ! :)
> If you want to experiment a bit with some options that really have an
> impact on quality (and speed also), make sure you read this:
> http://mplayerhq.hu/DOCS/HTML/en/menc-feat-dvd-mpeg4.html#menc-feat-dvd-
> mpeg4-lavc-encoding-options
> 

I have played around with a few of these in the past. I even tried Corey
Hickey's suggestion for Very High Quality in the "Call for Video Settings"
post:

mbd=2:mv0:trell:cbp:precmp=2:cmp=2:subcmp=2:predia=2:dia=2:preme=2:vme=5:naq
:v4mv:qns=2

It resulted in a 7 FPS encoding (as opposed to a roughly 50-60 that I
normally get in the first pass) and no real noticeable improvement in
picture quality. Really, I'm not willing to sacrifice much in terms of speed
at this point. I can barely keep up with all the encoding I have to do. 

Pete