Problems with b/w

[Shubin]

Hi,
I've made an animated logo for my film.
The whole picture is b/w and most (~95%) of it
is static. It is made in AviSynth from bitmap picture.
It showed big problems when playing.
The picture freezes and remains still until
a new key frame appears.
I also noticed those magenta or green artifacts
mentioned in FAQ in two color movies - b/w with
sepia filter. Some parts of my film are b/w, some
are color, so I'm not going to use the
b/w option of XVID.
Q: Is XVID really bad in encoding two-color clips
or I am doing something wrong ?

[Rober2D2]

When you say b/w, do you mean pure white + pure black or grayscale. I have encoded several grayscale films and I found no problem, except if I activate the grayscale option, that seems to have some problems in latest versions.

Saying the settings you have used might also help. Xvid settings, avisynth script ...

[Shubin]

Originally posted by Rober2D2
When you say b/w, do you mean pure white + pure black or grayscale.

Well, there is no such thing as pure white + pure black. Even if the original image is made this way, the compression algorithm will
add some distortion to it.
Of course, the image I am using is anti-aliased, but it has very high contrast. But it looks like the problem appears because the logo is perfectly still - it is just the same picture, repeated (loop-ed) in many frames.