[MEncoder-users] NTSC and Questions about quality

[Guillaume POIRIER]

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).


> 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've tested the bitrates down as low as 600 and while that was noticeable,
> at around 800, the image quality is almost the same as 1100. I'm trying to
> decide if the difference in quality is worth the space savings.

Maybe you should borrow someone else's eyes to do a blind test,
possibly on a different monitor than yours, as on CRT monitors
blocking artifacts are not as visible as on TFT monitors.

Guillaume
-- 
I feel sorry for people who don't drink.
When they wake up in the morning, that's
as good as they're going to feel all day.
 -- Frank Sinatra